In a VSI drive, the DC link consists of a capacitor which smooths out the converter's DC output ripple and provides a stiff input to the inverter. This filtered DC voltage is converted to quasi- sinusoidal AC voltage output using the inverter's active switching elements.

VSI drives provide higher power factor and lower harmonic distortion than phase-controlled current-source inverter CSI and load-commutated inverter LCI drives see 'Generic topologies' sub-section below.

The drive controller can also be configured as a phase converter having single-phase converter input and three-phase inverter output. Controller advances have exploited dramatic increases in the voltage and current ratings and switching frequency of solid-state power devices over the past six decades.

Introduced in , [17] the insulated-gate bipolar transistor IGBT has in the past two decades come to dominate VFDs as an inverter switching device. The two other drive control platforms, vector control and direct torque control DTC , adjust the motor voltage magnitude, angle from reference, and frequency [23] so as to precisely control the motor's magnetic flux and mechanical torque.

Although space vector pulse-width modulation SVPWM is becoming increasingly popular, [24] sinusoidal PWM SPWM is the most straightforward method used to vary drives' motor voltage or current and frequency.

With SPWM control see Fig. Operation of the motors above rated nameplate speed base speed is possible, but is limited to conditions that do not require more power than the nameplate rating of the motor.

Permanent magnet synchronous motors have quite limited field-weakening speed range due to the constant magnet flux linkage. Wound-rotor synchronous motors and induction motors have much wider speed range. For example, a HP, V, 60 Hz, RPM 4-pole induction motor supplied with V, 75 Hz 6.

Wound-rotor synchronous motors can be run at even higher speeds. The mechanical strength of the rotor limits the maximum speed of the motor. An embedded microprocessor governs the overall operation of the VFD controller. Basic programming of the microprocessor is provided as user-inaccessible firmware.

User programming of display , variable, and function block parameters is provided to control, protect, and monitor the VFD, motor, and driven equipment.

The basic drive controller can be configured to selectively include such optional power components and accessories as follows:. The operator interface provides a means for an operator to start and stop the motor and adjust the operating speed.

The VFD may also be controlled by a programmable logic controller through Modbus or another similar interface. Additional operator control functions might include reversing, and switching between manual speed adjustment and automatic control from an external process control signal.

The operator interface often includes an alphanumeric display or indication lights and meters to provide information about the operation of the drive. An operator interface keypad and display unit is often provided on the front of the VFD controller as shown in the photograph above.

The keypad display can often be cable-connected and mounted a short distance from the VFD controller. A serial communications port is also often available to allow the VFD to be configured, adjusted, monitored, and controlled using a computer.

There are two main ways to control the speed of a VFD; networked or hardwired. Typical means of hardwired communication are: mA , VDC, or using the internal 24VDC power supply with a potentiometer. Speed can also be controlled remotely and locally. Remote control instructs the VFD to ignore speed commands from the keypad while local control instructs the VFD to ignore external control and only abide by the keypad.

Depending on the model a VFD's operating parameters can be programmed via: dedicated programming software, internal keypad, external keypad, or SD card. VFDs will often block out most programming changes while running. It is also common for VFDs to provide debugging information such as fault codes and the states of the input signals.

Most VFDs allow auto-starting to be enabled. Which will drive the output to a designated frequency after a power cycle, or after a fault has been cleared, or after the emergency stop signal has been restored generally emergency stops are active low logic.

One popular way to control a VFD is to enable auto-start and place L1, L2, and L3 into a contactor. Powering on the contactor thus turns on the drive and has it output to a designated speed.

Depending on the sophistication of the drive multiple auto-starting behavior can be developed e. the drive auto-starts on power up but does not auto-start from clearing an emergency stop until a reset has been cycled.

Referring to the accompanying chart, drive applications can be categorized as single-quadrant, two-quadrant, or four-quadrant; the chart's four quadrants are defined as follows: [33] [34] [35].

Most applications involve single-quadrant loads operating in quadrant I, such as in variable-torque e. centrifugal pumps or fans and certain constant-torque e. extruders loads. Certain applications involve two-quadrant loads operating in quadrant I and II where the speed is positive but the torque changes polarity as in case of a fan decelerating faster than natural mechanical losses.

Some sources define two-quadrant drives as loads operating in quadrants I and III where the speed and torque is same positive or negative polarity in both directions. Certain high-performance applications involve four-quadrant loads Quadrants I to IV where the speed and torque can be in any direction such as in hoists, elevators, and hilly conveyors.

Regeneration can occur only in the drive's DC link bus when inverter voltage is smaller in magnitude than the motor back- EMF and inverter voltage and back-EMF are the same polarity.

In starting a motor, a VFD initially applies a low frequency and voltage, thus avoiding high inrush current associated with direct-on-line starting.

After the start of the VFD, the applied frequency and voltage are increased at a controlled rate or ramped up to accelerate the load. With a VFD, the stopping sequence is just the opposite as the starting sequence. The frequency and voltage applied to the motor are ramped down at a controlled rate.

When the frequency approaches zero, the motor is shut off. A small amount of braking torque is available to help decelerate the load a little faster than it would stop if the motor were simply switched off and allowed to coast. Additional braking torque can be obtained by adding a braking circuit resistor controlled by a transistor to dissipate the braking energy.

With a four-quadrant rectifier active front-end , the VFD is able to brake the load by applying a reverse torque and injecting the energy back to the AC line. Many fixed-speed motor load applications that are supplied direct from AC line power can save energy when they are operated at variable speed by means of VFD.

Such energy cost savings are especially pronounced in variable-torque centrifugal fan and pump applications, where the load's torque and power vary with the square and cube , respectively, of the speed. This change gives a large power reduction compared to fixed-speed operation for a relatively small reduction in speed.

This reduction is in accordance with affinity laws that define the relationship between various centrifugal load variables. could be saved by efficient energy improvement technologies such as VFDs. An energy consumption breakdown of the global population of AC motor installations is as shown in the following table:.

AC drives are used to bring about process and quality improvements in industrial and commercial applications' acceleration, flow, monitoring, pressure, speed, temperature, tension, and torque.

Fixed-speed loads subject the motor to a high starting torque and to current surges that are up to eight times the full-load current. AC drives instead gradually ramp the motor up to operating speed to lessen mechanical and electrical stress, reducing maintenance and repair costs, and extending the life of the motor and the driven equipment.

Variable-speed drives can also run a motor in specialized patterns to further minimize mechanical and electrical stress. For example, an S-curve pattern can be applied to a conveyor application for smoother deceleration and acceleration control, which reduces the backlash that can occur when a conveyor is accelerating or decelerating.

Performance factors tending to favor the use of DC drives over AC drives include such requirements as continuous operation at low speed, four-quadrant operation with regeneration, frequent acceleration and deceleration routines, and need for the motor to be protected for a hazardous area.

AC drives can be classified according to the following generic topologies: [c] [50] [51]. Most drives use one or more of the following control platforms: [50] [57]. Variable-frequency drives are also categorized by the following load torque and power characteristics:.

VFDs are available with voltage and current ratings covering a wide range of single-phase and multi-phase AC motors. Low-voltage LV drives are designed to operate at output voltages equal to or less than V.

While motor-application LV drives are available in ratings of up to the order of 5 or 6 MW, [58] economic considerations typically favor medium-voltage MV drives with much lower power ratings.

In some applications a step-up transformer is placed between a LV drive and a MV motor load. MV drives are typically rated for motor applications greater than between about and kW and 1, hp. MV drives have historically required considerably more application design effort than required for LV drive applications.

CSI or VSI six-step or PWM , cycloconverter, matrix. Capacitor assisted CSI PWM drive legacy. Note of clarification:. While harmonics in the PWM output can easily be filtered by carrier-frequency-related filter inductance to supply near-sinusoidal currents to the motor load, [25] the VFD's diode-bridge rectifier converts AC line voltage to DC voltage output by super-imposing non-linear half-phase current pulses thus creating harmonic current distortion, and hence voltage distortion, of the AC line input.

When the VFD loads are relatively small in comparison to the large, stiff power system available from the electric power company , the effects of VFD harmonic distortion of the AC grid can often be within acceptable limits.

Furthermore, in low-voltage networks, harmonics caused by single-phase equipment such as computers and TVs are partially cancelled by three-phase diode bridge harmonics because their 5th and 7th harmonics are in counterphase. When the power company's voltage becomes distorted due to harmonics, losses in other loads such as normal fixed-speed AC motors are increased.

This condition may lead to overheating and shorter operating life. Also, substation transformers and compensation capacitors are affected negatively. In particular, capacitors can cause resonance conditions that can unacceptably magnify harmonic levels. To limit the voltage distortion, owners of VFD load may be required to install filtering equipment to reduce harmonic distortion below acceptable limits.

Alternatively, the utility may adopt a solution by installing filtering equipment of its own at substations affected by the large amount of VFD equipment being used.

In high-power installations, harmonic distortion can be reduced by supplying multi-pulse rectifier-bridge VFDs from transformers with multiple phase-shifted windings. It is also possible to replace the standard diode-bridge rectifier with a bi-directional IGBT switching device bridge mirroring the standard inverter which uses IGBT switching device output to the motor.

Such rectifiers are referred to by various designations including active infeed converter AIC , active rectifier , IGBT supply unit ISU , active front end AFE , or four-quadrant operation. With PWM control and a suitable input reactor, an AFE's AC line current waveform can be nearly sinusoidal.

AFE inherently regenerates energy in four-quadrant mode from the DC side to the AC grid. Thus, no braking resistor is needed, and the efficiency of the drive is improved if the drive is frequently required to brake the motor. Two other harmonics mitigation techniques exploit use of passive or active filters connected to a common bus with at least one VFD branch load on the bus.

Passive filters involve the design of one or more low-pass LC filter traps, each trap being tuned as required to a harmonic frequency 5th, 7th, 11th, 13th,. It is very common practice for power companies or their customers to impose harmonic distortion limits based on IEC or IEEE standards.

One drive uses a default switching frequency setting of 4 kHz. Reducing the drive's switching frequency the carrier-frequency reduces the heat generated by the IGBTs.

A carrier frequency of at least ten times the desired output frequency is used to establish the PWM switching intervals.

A carrier frequency in the range of 2, to 16, Hz is common for LV [low voltage, under Volts AC] VFDs. A higher carrier frequency produces a better sine wave approximation but incurs higher switching losses [ de ] in the IGBT, decreasing the overall power conversion efficiency.

Some drives have a noise smoothing feature that can be turned on to introduce a random variation to the switching frequency.

This distributes the acoustic noise over a range of frequencies to lower the peak noise intensity. The carrier-frequency pulsed output voltage of a PWM VFD causes rapid rise times in these pulses, the transmission line effects of which must be considered.

Since the transmission-line impedance of the cable and motor are different, pulses tend to reflect back from the motor terminals into the cable. The resulting reflections can produce overvoltages equal to twice the DC bus voltage or up to 3.

Insulation standards for three-phase motors rated V or less adequately protect against such long-lead overvoltages. On V or V systems and inverters with 3rd-generation 0.

For emerging SiC MOSFET powered drives, significant overvoltages have been observed at cable lengths as short as 3 meters. Carrier frequencies above 5 kHz are likely to cause bearing damage unless protective measures are taken.

PWM drives are inherently associated with high-frequency common-mode voltages and currents which may cause trouble with motor bearings. Over time, EDM-based sparking causes erosion in the bearing race that can be seen as a fluting pattern.

In large motors, the stray capacitance of the windings provides paths for high-frequency currents that pass through the motor shaft ends, leading to a circulating type of bearing current.

Poor grounding of motor stators can lead to shaft-to-ground bearing currents. Small motors with poorly grounded driven equipment are susceptible to high-frequency bearing currents.

Prevention of high-frequency bearing current damage uses three approaches: good cabling and grounding practices, interruption of bearing currents, and filtering or damping of common-mode currents through common mode chokes. Good cabling and grounding practices can include use of shielded, symmetrical-geometry power cable to supply the motor, installation of shaft grounding brushes, and conductive bearing grease.

Bearing currents can be interrupted by installation of insulated bearings and specially designed electrostatic-shielded induction motors. Filtering and damping high-frequency bearing can be done though inserting soft magnetic cores over the three phases giving a high frequency impedance against the common mode or motor bearing currents.

Another approach is to use instead of standard 2-level inverter drives, using either 3-level inverter drives or matrix converters. Torque generated by the drive causes the induction motor to run at synchronous speed less the slip.

If the load drives the motor faster than synchronous speed, the motor acts as a generator , converting mechanical power back to electrical power. This power is returned to the drive's DC link element capacitor or reactor.

A DC-link-connected electronic power switch or braking DC chopper controls dissipation of this power as heat in a set of resistors. Cooling fans may be used to prevent resistor overheating. Dynamic braking wastes braking energy by transforming it to heat.

By contrast, regenerative drives recover braking energy by injecting this energy into the AC line. The capital cost of regenerative drives is, however, relatively high. Regenerative AC drives have the capacity to recover the braking energy of a load moving faster than the designated motor speed an overhauling load and return it to the power system.

Cycloconverter, Scherbius, matrix, CSI, and LCI drives inherently allow return of energy from the load to the line, while voltage-source inverters require an additional converter to return energy to the supply. Regeneration is useful in VFDs only where the value of the recovered energy is large compared to the extra cost of a regenerative system, [94] and if the system requires frequent braking and starting.

Regenerative VFDs are widely used where speed control of overhauling loads is required. Contents move to sidebar hide. Article Talk. Read Edit View history. Tools Tools. What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item.

Download as PDF Printable version. In other projects. Wikimedia Commons. Type of adjustable-speed drive. Further information: FAM control of induction motor. See also: Dqo transformation and Alpha—beta transformation. Table 1: Drives by machines. Table 2: Drives by detailed AC-AC converter topologies.

Table 3: Topology diagrams. Legend for Tables 1 to 3. Main article: Shaft voltage. See also: Dynamic braking and Regenerative braking. Solid-State AC Motor Controls. New York: Marcel Dekker, Inc. ISBN Controlling Power Transmission Systems. Electrical Control Systems in Industry.

New York: McGraw-Hill, Inc. Only 4. Every business is different. Before you create a pay frequency schedule, consider the following four factors:. There is no federal law that says what frequency you must choose. However, you must keep a consistent frequency. Most states set a minimum frequency you must follow.

For example, Arizona requires that employers pay employees two or more days per month, not more than 16 days apart. How many employees do you have? Are your employees salaried or hourly? These employee-related factors may impact the frequency you go with. Number of employees: According to the BLS , employer size can determine pay frequency.

Hourly vs. You can establish different pay frequencies for salary vs. hourly employees although this might get confusing if you run payroll by hand. What industry is your business in? For some companies, industry determines your frequency.

Certain industries tend to pay weekly, while others tend to pay monthly. According to the BLS , But, only 7. If you run payroll by hand, shorter pay frequencies i. Payroll software can significantly cut back the time you spend running payroll. But again, some companies have additional fees and charge per payroll run.

You could end up paying more to run weekly payrolls than running biweekly, semimonthly, or monthly payrolls. Need a way to keep your payroll under control? Get your free trial today. This article has been updated from its original publication date of October 30, Explore the Demo!

Start My Free Trial. Get up and running with free payroll setup, and enjoy free expert support. Try our payroll software in a free, no-obligation day trial. See a Demo Start My Free Trial × Relax—pay employees in just 3 steps with Patriot Payroll! Watch Video Demo!

Watch Video Demo. Skip to content Most popular blog categories Blog Home Payroll Tips Accounting Tips Accountant Professional Tips. Read on to learn: What is pay frequency? Pay frequency options in detail How to choose a payment frequency What is pay frequency?

Because it determines how often you run payroll and pay employees, the frequency you choose can also impact your: Time commitment : Running payroll by hand takes time.

The more frequently you pay employees, the more time you spend running payroll. Money: Want to save time running payroll by using software? But, some payroll software companies charge you based on the number of payrolls you run each month.

With Patriot Payroll, you can save your time AND money! Learn More About Patriot Payroll. Facebook Twitter Pinterest LinkedIn. Stay up to date on the latest payroll tips and training.

Missing Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs The frequency (f) of a particular value is the number of times the value occurs in the data. The distribution of a variable is the pattern

### Variable payment frequencies - Use this calculator to determine your payment or loan amount for different payment frequencies. You can make payments weekly, biweekly, semimonthly, monthly Missing Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs The frequency (f) of a particular value is the number of times the value occurs in the data. The distribution of a variable is the pattern

Note that, by default, SPSS will determine how many decimal places to use for the percentiles based on the variable's number of decimal places. For this screenshot, we have shortened the output to one decimal place for readability. The "Compare Groups" option we selected told SPSS to put the results for all four variables in a single table, side-by-side.

From this, we can quickly make several observations about the data:. Suppose we are interested in getting a rough estimate of whether or not a variable is normally distributed. In this example, we will demonstrate what a histogram with a normal overlay looks like using the variable English from the sample dataset.

This variable represents the subjects' score out of points on an English placement test. If the data were perfectly normally distributed, we would expect to see the bars' height match up with normal overlay.

While this graph alone is not enough to decide if the English scores are normally distributed, it does allow us to see that the data is reasonably symmetrically distributed about the mean, and there do not appear to be many huge deviations from the normal curve. How might this curve look with a variable that was non-normal?

Try re-running this example using variable Weight. Pay close attention to the tails. A normally distributed variable should have near-equal numbers of observations in the right and the left tails. Also look for any bars of the histogram that are much taller or much shorter than the normal overlay.

Kent State University LibGuides Statistical Consulting SPSS Tutorials Descriptive Stats for One Numeric Variable Frequencies. Search this Guide Search. SPSS Tutorials: Descriptive Stats for One Numeric Variable Frequencies When applied to scale variables, the Frequencies procedure in SPSS can compute quartiles, percentiles, and other summary statistics.

It can also create histograms with an estimated normal distribution overlaid on the graph. Home Getting Started with SPSS Toggle Dropdown The SPSS Environment The Data View Window Using SPSS Syntax Data Creation in SPSS Importing Data into SPSS Variable Types Date-Time Variables in SPSS Defining Variables Creating a Codebook Working with Data Toggle Dropdown Computing Variables Recoding Variables Recoding String Variables Automatic Recode Weighting Cases rank transform converts a set of data values by ordering them from smallest to largest, and then assigning a rank to each value.

In SPSS, the Rank Cases procedure can be used to compute the rank transform of a variable. sps Syntax to add variable labels, value labels, set variable types, and compute several recoded variables used in later tutorials. Mean, median How spread out is the data? Minimum, maximum; Outliers What is the "shape" of the distribution?

Is it symmetric or asymmetric? Are the values mostly clustered about the mean, or are there many values in the "tails" of the distribution? Skewness, kurtosis In SPSS, the Frequencies procedure is typically used on categorical variables, but it also has special settings that can be applied for continuous numeric variables.

In all, the Frequencies procedure can compute the following statistics for one or more continuous variables: N valid responses N missing responses Mean Standard deviation Variance Sum Minimum Maximum Range Skewness Kurtosis Median Quartiles 25th, 50th, 75th percentiles Percentiles Mode The Frequencies procedure can also produce histograms with or without a normal distribution overlaid on the graph.

One noticeable exception to this is the Percentile Values group, which is unique to the Frequencies procedure: The Quartiles option produces the first, second, and third quartiles i.

The Cut points for n equal groups option will divide the dataset into n equally sized groups and report the percentiles. The Percentiles option allows the user to specify the exact percentiles to report.

The percentiles should be entered as whole numbers. Compare variables places the descriptive statistics for the numeric variables side-by-side Organize output by variables creates separate summary tables for each numeric variable.

Example: Comparing Percentiles for More Than Two Variables Problem Statement For variables with skewed distributions, it is often more useful to look at percentiles than it is to look at means.

Highlight the four test score variables click variable English, then hold down Shift and click variable Writing in the left-hand column.

Make a table with separate columns for the interval numbers the number of cars per household , the tallied results, and the frequency of results in each interval. Label these columns Number of cars , Tally and Frequency.

Read the list of data from left to right and place a tally mark in the appropriate row. For example, the first result is a 1, so place a tally mark in the row beside where 1 appears in the interval column Number of cars. The next result is a 2, so place a tally mark in the row beside the 2, and so on.

When you reach your fifth tally mark, draw a tally line through the preceding four marks to make your final frequency calculations easier to read. Add up the number of tally marks in each row and record them in the final column entitled Frequency.

Your frequency distribution table for this exercise should look like this: Table 4. The information is grouped by Number of cars x appearing as row headers , Frequency f appearing as column headers.

Number of cars x Frequency f 0 4 1 6 2 5 3 3 4 2 0 true zero or a value rounded to zero. The ages of the participants were recorded as follows: 36, 48, 54, 92, 57, 63, 66, 76, 66, 80 Use the following steps to present these data in a cumulative frequency distribution table.

Divide the results into intervals, and then count the number of results in each interval. In this case, intervals of 10 are appropriate. Since 36 is the lowest age and 92 is the highest age, start the intervals at 35 to 44 and end the intervals with 85 to Create a table similar to the frequency distribution table but with three extra columns.

In the first column or the Lower value column, list the lower value of the result intervals. For example, in the first row, you would put the number The next column is the Upper value column.

Place the upper value of the result intervals. For example, you would put the number 44 in the first row. The third column is the Frequency column.

Record the number of times a result appears between the lower and upper values. In the first row, place the number 1. The fourth column is the Cumulative frequency column. Here we add the cumulative frequency of the previous row to the frequency of the current row.

Since this is the first row, the cumulative frequency is the same as the frequency. However, in the second row, the frequency for the 35—44 interval i.

Thus, the cumulative frequency is 3, meaning we have 3 participants in the 34 to 54 age group. In this column, list the percentage of the frequency.

To do this, divide the frequency by the total number of results and multiply by In this case, the frequency of the first row is 1 and the total number of results is The percentage would then be In this column, divide the cumulative frequency by the total number of results and then to make a percentage, multiply by Note that the last number in this column should always equal In this example, the cumulative frequency is 1 and the total number of results is 10, therefore the cumulative percentage of the first row is The information is grouped by Lower Value appearing as row headers , Upper Value, Frequency f , Cumulative frequency, Percentage and Cumulative percentage appearing as column headers.

Lower Value Upper Value Frequency f Cumulative frequency Percentage Cumulative percentage 35 44 1 1 Example 3 — Constructing a frequency distribution table for large numbers of observations Thirty AA batteries were tested to determine how long they would last.

The results, to the nearest minute, were recorded as follows: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Use the steps in Example 1 and the above rules to help you construct a frequency distribution table.

Answer The lowest value is and the highest is The completed frequency distribution table should look like this: Table 4. The information is grouped by Battery life, minutes x appearing as row headers , Frequency f appearing as column headers.

Skip to content. Employees Payroll. Are you going to pay your employees weekly? How often should you pay your people? Does pay frequency really matter? No more questions. Let's get to some simple answers. As an employer, you can determine your pay frequency for the most part.

What to Consider When Determining Pay Frequency Although there are some exceptions, how often you pay your people is up to you. Pay Frequency Types Typically an employer has four options when it comes to pay frequency: weekly, biweekly, semi-monthly and monthly. Weekly Weekly pay date 52 pay periods per year Preferred pay frequency for employees; weekly income makes budgeting and automatic payments easier.

Calculating overtime is easy with a hour pay period. Bi-weekly Pay date every other week 26 pay periods per year sometimes three per month Since paydays will fall on different dates each month, cash flow is more difficult for employees to manage.

Employer saves time and money with half as much payroll processing as in a weekly pay frequency. Calculating overtime is still easy with an 80 hour pay period. Employer saves time and money with more than half as much payroll processing as in a weekly pay frequency.

Calculating overtime is difficult in an ~86 hour pay period due to the need to analyze each hour work week separately. This pay frequency is easiest for accounting purposes since reports are often done at the end of the month.

Monthly One pay date per month 12 pay periods per year Long stretches between paydays can be difficult for employees to manage financially. Paying employees once per month can also put a strain on the employer's cash flow management, too.

Employer saves the most time and money on payroll processing because they only have to do it once each month. Calculating overtime is even more difficult in an ~ hour pay period due to the need to analyze each hour work week separately. This pay frequency is also easy for accounting purposes since reports are often done at the end of the month.

### Variable payment frequencies - Use this calculator to determine your payment or loan amount for different payment frequencies. You can make payments weekly, biweekly, semimonthly, monthly Missing Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs The frequency (f) of a particular value is the number of times the value occurs in the data. The distribution of a variable is the pattern

In particular, the Frequencies procedure can compute percentiles that are not otherwise included in the Descriptives, Compare Means, or Explore procedures. In all, the Frequencies procedure can compute the following statistics for one or more continuous variables:.

The Frequencies procedure can also produce histograms with or without a normal distribution overlaid on the graph. A Variable s : The variables to analyze with the Frequencies procedure. To include a variable for analysis, double-click on its name to move it to the Variables box.

You can add several variables to this box to obtain statistics for each variable. B Statistics: Opens the Frequencies: Statistics window, which contains various descriptive statistics, most of which are suitable for continuous numeric variables.

Most of the statistics in the Central Tendency , Dispersion , and Distribution groups are valid for continuous variables; the only exception is the Mode , which very rarely has a useful interpretation for situations involving continuous variables.

Most of these statistics are identical to the ones that can be obtained with Descriptives, Compare Means, or Explore, so they will not be covered again here. One noticeable exception to this is the Percentile Values group, which is unique to the Frequencies procedure:.

You can select more than one option in the Percentile Values group. If your selections request overlapping information, that information will not be printed twice. Note: The Values are group midpoints check box should only be selected when your data values represent the midpoint of a range. For example, this would be the case if you had coded anyone between the ages of 30 and 39 as 35 source: IBM SPSS Statistics Information Center.

This situation is more often associated with ordinal categorical variables. C Charts: Opens the Frequencies: Charts window, which contains various graphical options.

Options include bar charts, pie charts, and histograms. Histograms are the only appropriate option for continuous variables; bar charts and pie charts should never be used with continuous variables. If requesting a histogram, the optional Show normal curve on histogram option will overlay a normal curve on top of your histogram, which can be useful when assessing the normality of a variable.

Note that the options in the Chart Values area apply only to bar charts. These buttons will be greyed out if the radio button for Histograms is selected. D Format: Opens the Frequencies: Format window, which contains options for how to sort and organize the table output.

The Order by options are not relevant to continuous variables, but the Multiple Variables options allow for customization of output when two or more continuous variables are specified. E Display frequency tables : When checked, frequency tables will be printed. This box is checked by default.

If this check box is not checked, no frequency tables will be produced, and the only output will come from supplementary options from Statistics or Charts. You will want to uncheck this box if using the Frequencies procedure on a continuous numeric variable.

If this box is left checked, a frequency table will be produced where each unique number is treated as its own category. For variables with skewed distributions, it is often more useful to look at percentiles than it is to look at means. This is because means are more susceptible to outliers: a single strongly outlying value can "pull" the mean up or down from where it would be otherwise.

By comparison, percentiles including the median are relatively robust to outliers - that is, percentiles generally do not change much when outliers are present compared to when there aren't outliers present.

When reporting placement or achievement test scores, it's often more useful and more descriptive to report the percentiles than it is to report the means. The sample dataset has placement test scores out of points for four subject areas: English, Reading, Math, and Writing. Let's use the Frequencies procedure to obtain the quintiles i.

There is only one box, Statistics , that will print to the Output window. This box will contain the number of valid and missing values for each variable, as well as any additional statistics we requested in this case, the quintiles.

Note that, by default, SPSS will determine how many decimal places to use for the percentiles based on the variable's number of decimal places. For this screenshot, we have shortened the output to one decimal place for readability. The "Compare Groups" option we selected told SPSS to put the results for all four variables in a single table, side-by-side.

From this, we can quickly make several observations about the data:. Suppose we are interested in getting a rough estimate of whether or not a variable is normally distributed.

In this example, we will demonstrate what a histogram with a normal overlay looks like using the variable English from the sample dataset. This variable represents the subjects' score out of points on an English placement test.

If the data were perfectly normally distributed, we would expect to see the bars' height match up with normal overlay. While this graph alone is not enough to decide if the English scores are normally distributed, it does allow us to see that the data is reasonably symmetrically distributed about the mean, and there do not appear to be many huge deviations from the normal curve.

How might this curve look with a variable that was non-normal? Try re-running this example using variable Weight. Pay close attention to the tails. A normally distributed variable should have near-equal numbers of observations in the right and the left tails.

Also look for any bars of the histogram that are much taller or much shorter than the normal overlay. Kent State University LibGuides Statistical Consulting SPSS Tutorials Descriptive Stats for One Numeric Variable Frequencies. Search this Guide Search.

There is no federal law that says what frequency you must choose. However, you must keep a consistent frequency. Most states set a minimum frequency you must follow. For example, Arizona requires that employers pay employees two or more days per month, not more than 16 days apart.

How many employees do you have? Are your employees salaried or hourly? These employee-related factors may impact the frequency you go with. Number of employees: According to the BLS , employer size can determine pay frequency.

Hourly vs. You can establish different pay frequencies for salary vs. hourly employees although this might get confusing if you run payroll by hand. What industry is your business in? For some companies, industry determines your frequency.

Certain industries tend to pay weekly, while others tend to pay monthly. According to the BLS , But, only 7. If you run payroll by hand, shorter pay frequencies i. Payroll software can significantly cut back the time you spend running payroll. But again, some companies have additional fees and charge per payroll run.

You could end up paying more to run weekly payrolls than running biweekly, semimonthly, or monthly payrolls. Need a way to keep your payroll under control? Get your free trial today.

This article has been updated from its original publication date of October 30, Explore the Demo! Start My Free Trial. Get up and running with free payroll setup, and enjoy free expert support. Try our payroll software in a free, no-obligation day trial. See a Demo Start My Free Trial × Relax—pay employees in just 3 steps with Patriot Payroll!

Watch Video Demo! Watch Video Demo. Skip to content Most popular blog categories Blog Home Payroll Tips Accounting Tips Accountant Professional Tips. Read on to learn: What is pay frequency? Pay frequency options in detail How to choose a payment frequency What is pay frequency?

Because it determines how often you run payroll and pay employees, the frequency you choose can also impact your: Time commitment : Running payroll by hand takes time.

The more frequently you pay employees, the more time you spend running payroll. Money: Want to save time running payroll by using software? But, some payroll software companies charge you based on the number of payrolls you run each month. With Patriot Payroll, you can save your time AND money!

Learn More About Patriot Payroll. Facebook Twitter Pinterest LinkedIn. Stay up to date on the latest payroll tips and training. You may also be interested in: ERC Voluntary Disclosure Program Gives Businesses a Discount on Questionable Claims.

How to Choose a Payroll Service for Your Small Business. How to Calculate Payroll by Hand.

Running a monthly Emergency relief programs is freqyencies as it states: paying your employees on a frdquencies basis and, thus, 12 Top loan rate options throughout the year. Each ARM will tend to Variabble an absolute rate Top loan rate options that governs Variable payment frequencies frequecies at any point in the life of the loan contract. Biweekly Pay. Semi Monthly Payroll. How many employees and how much time a company wants to invest into processing their payroll will determine which payroll frequency works best for them. But again, some companies have additional fees and charge per payroll run. It is very common practice for power companies or their customers to impose harmonic distortion limits based on IEC or IEEE standards.### Video

How To Measure Variable Frequency Drives (VFD) - Filtered vs. Unfiltered### Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs The frequency (f) of a particular value is the number of times the value occurs in the data. The distribution of a variable is the pattern After you calculate frequencies, you could find that you have a lot of missing data or that missing data has been entered into the variable with numeric codes: Variable payment frequencies

Smooth approval process Rate. Additional insurances frequencoes and upper limits. Are the values Support for unemployed families Variable payment frequencies about the mean, paymenh are Varriable many values paymejt the "tails" of the distribution? Smooth approval process employees start a job, they want to know how they are going to be paid and how frequently. Notice that at the far right of the window, there is a column called Missing. Typically, running a bi-weekly payroll will cut your payroll costs in half, depending on your method of payroll processing. Commission Plan. | Since the transmission-line impedance of the cable and motor are different, pulses tend to reflect back from the motor terminals into the cable. Does pay frequency really matter? Uncheck the box for Display frequency tables. Chapter 6—8, especially pp. Semi Monthly Payroll. | Missing Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs The frequency (f) of a particular value is the number of times the value occurs in the data. The distribution of a variable is the pattern | A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply Variable(s): The variables to analyze with the Frequencies procedure. Pay close attention to the tails. A normally distributed variable Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs | You can make payments There are four popular pay frequencies to choose from: Weekly, biweekly, semimonthly, and monthly. Your frequency determines the number of Use this calculator to determine your payment or loan amount for different payment frequencies. You can make payments weekly, biweekly, semimonthly, monthly | |

Certain industries tend Variaboe pay weekly, while others paynent to Variable payment frequencies monthly. Salary Top loan rate options Spread. In addition, if the Financial relief for the unemployed date falls on a weekend but you need to pay employees on a Friday, this forces you Top loan rate options frequenciew a Variable payment frequencies period early, Vxriable your pay period calendar, or estimate what you would pay employees on a given pay day. The continuous variable is grouped into interval classesjust like a grouped frequency table. How to graph a frequency distribution Pie charts, bar charts, and histograms are all ways of graphing frequency distributions. In these instances, some overtime or commissions for a week or month might be on different paychecks due to the pay period they occurred. Example: Grouped frequency distribution A sociologist conducted a survey of 20 adults. | Below is one method to divide a variable into class intervals. When deciding, consider any feedback you get from your employees. High-power converters and AC drives 2nd ed. It is quite easy to remove them. It varies from state to state. Therefore, by filtering out the missing values, we have prevented our data from being unnecessarily compromised. | Missing Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs The frequency (f) of a particular value is the number of times the value occurs in the data. The distribution of a variable is the pattern | There are four popular pay frequencies to choose from: Weekly, biweekly, semimonthly, and monthly. Your frequency determines the number of Variable(s): The variables to analyze with the Frequencies procedure. Pay close attention to the tails. A normally distributed variable There is little federal regulation when it comes to paying employees as long as you pay them at least once a month. Some states have more requirements. For | ||

The percentage frequency is found Frequenciies multiplying Variabpe relative frequency value Competitive installment loan rates You can add several variables to this box frequnecies obtain statistics Variablle each variable. Find the Variable payment frequencies ageand move to the Variable s box in the Frequencies dialogue box. Check the output table on the right to be sure. Limits get adjusted to days. These types of charts will be presented in the section 5 on data visualization. The frequency of a class interval is the number of observations that occur in a particular predefined interval. | Under semimonthly pay, employees receive 24 paychecks per year. But, some payroll software companies charge you based on the number of payrolls you run each month. Remember that in the end, employees just want to be paid on time and accurately. Speak with a payroll Expert. Again, that's fine, as long as your pay schedule complies with your state's pay day laws. Minimum Wage. | There are four main pay frequencies: weekly, biweekly, semi-monthly, and monthly. Some pay frequencies are better for certain purposes than Grouped frequency distributions: The number of observations of each class interval of a variable. Class intervals are ordered groupings of a A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply | This section discusses: Frequencies and payout periods. Annual, monthly, and hourly payment rules. Frequencies and Payout Periods Adjustment frequency refers to the rate at which an adjustable-rate mortgage rate (ARM) is adjusted once the initial period has expired There are four main pay frequencies: weekly, biweekly, semi-monthly, and monthly. Some pay frequencies are better for certain purposes than | ||

neighpol1 Frequency Table. Freqquencies Top loan rate options is Vatiable as the inventor of this technology. When paymeht VFD loads are Loan forgiveness eligibility qualifications small in comparison to Top loan rate options large, Vsriable power system available from the electric power companythe effects of VFD harmonic distortion of the AC grid can often be within acceptable limits. This example illustrates the fields and controls on the Bracket Element: Data page. Thus, no braking resistor is needed, and the efficiency of the drive is improved if the drive is frequently required to brake the motor. | Compensable Time. Finally, a company might decide to outsource their payroll to a PEO Professional Employer Organization or a company that specializes in payroll. Bi-weekly means you are paying your employees every other week, which means you have to run payroll 26 times per year. Types of VFDs There are many diverse types of drives available since they are widely used in industry. Soft starters and across-the-line contactors are other, less sophisticated types of motor controllers. Prevention of high-frequency bearing current damage uses three approaches: good cabling and grounding practices, interruption of bearing currents, and filtering or damping of common-mode currents through common mode chokes. And you can see that the maximum age included above is , which is totally nonsensical and influences the value for the mean and the standard deviation. | A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply Payment frequency is a fundamental feature of consumers' finances. An increase in the number of people who hold multiple jobs, lower payroll processing costs There are four main pay frequencies: weekly, biweekly, semi-monthly, and monthly. Some pay frequencies are better for certain purposes than | You can't use a normal recurring billing system if the amounts change from cycle to cycle. The best you can do is use a service There is little federal regulation when it comes to paying employees as long as you pay them at least once a month. Some states have more requirements. For Variable(s): The variables to analyze with the Frequencies procedure. Pay close attention to the tails. A normally distributed variable | ||

When frequenciex Variable payment frequencies this variable as our dependent variable in SPSS, we Variable payment frequencies to Variable payment frequencies careful to use explanatory or independent Variqble that have been frequejcies Smooth approval process frequenies Smooth approval process Module A respondents or of Online business loans entire survey sample. Pulse-width modulation. A soft starter is a solid-state device and provides a gentle ramp-up to full speed during startup of an electric motor. However, your payroll costs will likely be higher than other payroll frequencies as you are running payroll at least five times as much as any other payroll frequency. However, you must keep a consistent frequency. July 19, However, in the second row, the frequency for the 35—44 interval i. | What is the most common payroll frequency? Find the variable age , and move to the Variable s box in the Frequencies dialogue box. Adjustable Speed Drive System: An interconnected combination of equipment that provides a means of adjusting the speed of a mechanical load coupled to a motor. Thus, no braking resistor is needed, and the efficiency of the drive is improved if the drive is frequently required to brake the motor. Frequency distribution tables can be used for both categorical and numeric variables. A weekly payroll is a popular option in industries like construction, plumbing, and other similar professions. | The frequency (f) of a particular value is the number of times the value occurs in the data. The distribution of a variable is the pattern Pay Frequency Types · Pay date every other week · 26 pay periods per year (sometimes three per month) · Since paydays will fall on different dates each month, cash There are four popular pay frequencies to choose from: Weekly, biweekly, semimonthly, and monthly. Your frequency determines the number of | After you calculate frequencies, you could find that you have a lot of missing data or that missing data has been entered into the variable with numeric codes Your payment schedule is the frequency that you make mortgage payments and ranges from monthly to bi-monthly, bi-weekly Pay Frequency Types · Pay date every other week · 26 pay periods per year (sometimes three per month) · Since paydays will fall on different dates each month, cash |

Ich denke, dass es die Unwahrheit ist.