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Know Your Power Supply Jargon: Regulation

Written on September 3, 2017 at 6:23 am, by

The Sorensen XG 1500 Series is an industry leading programmable DC power supply designed for test, production, laboratory,OEM and quality assurance applications. The XG 1500 is a 1500 Watt, 1U programmable power supply with constant voltage and constant current modes, automatic cross-over and numerous features enabling cost effective,easy integration.

The most important thing that a power supply does is to maintain a constant voltage output or a constant current output. This is true whether the power supply is built into a product and provides fixed output voltages, such as a desktop computer power supply, or a power supply that is on the test bench or is part of an automated test system that must provide variable outputs. We call this ability to maintain a constant output voltage or current regulation.

Load regulation

There are actually two types of regulation that you need to be aware of when selecting a power supply: load regulation and line regulation. Load regulation is the ability of a power supply to maintain a constant output voltage (or current) under under very light loads and under loads near the maximum current. That is to say that if you set the output voltage of a supply to say 10 VDC, the supply should be able to maintain its output at 10 VDC when no current is being drawn from the supply and when the maximum current is being drawn from the supply.

To see how this might work in practice, let’s take a look at the Sorensen XG 12.5-120, one of the supplies in the XG 1500 Series. It can supply up to 12.5 VDC at currents up to 120 A. The load regulation for the XG 1500 Series is specified to be 0.005% of rated output voltage + 2 mV. For a 10 V output, that works out to be 2.5 mV, from no load to 120 A.

Line regulation

The calculations for load regulation assumes that the AC input voltage will remain constant. Of course, this is not always the case. AC line voltage can change, and this can also affect the output of a power supply. The ability of a power supply to maintain a constant output voltage when the input voltage changes is called line regulation.

The line regulation for the XG 1500 Series is also 0.005% of rated output voltage + 2 mV, assuming a constant load. For a 10 V output, that works out to be 2.5 mV, with an input voltage of 85-132 VAC for the nominally 110 VAC model, or an input voltage of 170-265 VAC for the nominally 220 VAC model.

Load and line regulation aren’t the only specifications that affect a power supply’s output. In some applications, for example, transient response time is also important. Load and line regulation are baseline specifications, though. Without good line and load regulation, the other specifications are meaningless.

For more information on DC power supplies, and how to use them in your application, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

Sorensen SG Series ensures auto parts reliability

Written on August 28, 2017 at 7:31 am, by

One of the big challenges when designing and manufacturing auto parts is ensuring that they operate reliably in very hot environments, such as Dubai, where the high temperature can easily reach 40˚C. Of course, they must also operate reliably in very cold environments, such as Siberia, where the thermometer can drop to -40˚C or below. You certainly don’t want parts to fail when you’re zipping down the road at 200 km/hr. because they can’t take the heat (or the cold).

To ensure that their products don’t fail, most supplier will perform some kind of environmental testing. They will place the parts in an environmental test chamber and simulate the environment in which the component must operate. A computer is used to put the component through its paces while in the chamber.

The manufacturer of the electrically-powered, steering belt drive shown above designed just such a test. This drive features a modular design and can be used in vehicles as small as C-segment vehicles and as large as full size trucks. It can handle rack loads as high as 18kN and features a fully integrated steering gear that can be mounted in either inboard or outboard configurations.

The test system for this drive included:

  • An environmental test chamber capable of producing ambient temperatures as high as 85˚C and as low -40˚C. The chamber also has humidity control that enables it so simulate a wide range of operating environments.
  • A 19-in. rack to house the test system instrumentation.
  • A rack-mounted Sorensen SGA 20x500D DC power supply, with a GPIB interface, to supply power to the device under test (DUT).
  • Rack-mounted instrumentation required to monitor the output of the electrically-powered, steering belt drive’s sensors.
  • A rack-mounted computer running a test program to control the environmental chamber and the Sorensen SGA power supply. The computer simulates the drive’s ECU (Electronic Unit Control), sending commands to the drive’s actuators and measuring the drive’s sensor outputs. In addition to running the test, the computer outputs a test report once a test run is complete.

While a number of different temperature profiles is available with this system, a typical profile would look like the following:

  1. 23˚C for 30 minutes.
  2. -40˚C for six hours
  3. 85˚C for 70 hours

At these temperatures, the computer will run a series of performance tests to ensure that the drive will operate reliably at these temperatures. During the course of these tests, the DUT power supply voltage can also be varied to test the drive’s sensitivity to input power variations.

In most automotive applications, it is not necessary to use a DC power supply with fast rise and fall times, but a programmable power supply is a must to test input voltage sensitivity. The Sorensen SG Series is a good choice because they have a wide range of voltage and current capabilities which allow you to choose the model that’s right for your application. They also have very stable outputs, which is important because tests can last a long time.

For more information on how you can use Sorensen DC power supplies and other AMETEK Programmable Power products in automotive applicatons, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

How electronic loads work

Written on August 22, 2017 at 8:18 am, by

Electronic loads are used in a variety of tests, including power supply tests and battery tests. You can program them to provide exactly the kind of load that you need for the device you are testing.

One of the most common ways to use an electronic load is in the constant current (CC) mode. In this mode, the electronic load will draw a constant current from the device under test (DUT), no matter what the output voltage is. The figure below shows a simplified schematic of an electronic load to illustrate how the CC mode works.

Current from the device under test flows through both the power FET and the current shunt resistor. The voltage across the shunt resistor is compared to a voltage reference and the difference between the two is used to control the drain-to-source resistance, RDS, of the power FET. If the load current is higher than the desired constant current, the circuit will adjust the FET’s gate voltage to increase RDS and thus reduce the load current. If the load current is lower than the desired constant current, the circuit will adjust the gate voltage to reduce RDS, and the load current will increase.

In an actual electronic load, VREF is supplied by a digital-to-analog converter (DAC). The user sets the DAC output voltage to yield the desired constant-curent level. The CC accuracy specification is largely determined by the accuract of the digital-to-analog converter used in this circuit.

Constant-voltage mode

Most electronic loads also offer a constant-voltage (CV) mode. In this mode, the electronic load will maintain a constant voltage across the device under test. You would use this mode to test a battery charging circuit. The figure below shows a simplified schematic for an electronic load operating in constant-voltage mode.

In CV mode, the feedback signal is generated by a precision voltage divider. This signal is again compared to a voltage reference, and the output of the comparator is used to increase or decrease the RDS of the power FET. This basically changes the input impedance of the electronic load, allowing it to maintain a constant voltage across the input terminals, no matter how much current it is sinking.

Just like the CC mode, VREF is normally supplied by a digital-to-analog converter. Changing its output will change the CV value.

Modern electronic loads also offer constant-resistance (CR) and constant-power (CP) modes. The circuits used to implement these modes are usually some variation of the circuits used for the CC and CV modes. For more information on how electronic loads work, and how to use them in your applicaton, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

Minimize noise from power supplies when making low-level measurements

Written on August 1, 2017 at 7:22 am, by

Low-level measurements are susceptible to noise from a number of different sources. While discussing all the ways that noise can degrade low-level measurements is outside the scope of this article, let’s at least consider how to make sure that your test system power supply is not a problem:

  1. Start with a low-noise power supply. The first step to ensuring that noise doesn’t affect your test system’s low-level measurements is to use a low-noise power supply. In general, linear power supplies are less noisy than switching power supplies, and this makes them a better choice for powering test systems that must make low-level measurements. The Sorensen XT Series, for example, has an output noise and ripple specification of less than 1 mV.
  2. Use shielded cable to connect the power supply to a load. You can minimize the radiated noise picked up by the power supply leads by using twisted-pair, shielded cable for both the output and remote sense leads, as shown in the figure below.

    Connect the shield to ground at one end only, preferably the single-point ground on the supply, as shown. Another thing that you can do to reduce noise pickup is to use a common-mode choke in series with the output leads and a shunt capacitor from each lead to ground.

  3. Avoid imbalances in load lead inductance. By using shielded, twisted-pair cable to connect the supply to the load, you ensure that the leads are the same length, which helps you avoid any imbalance in the leads. Directly connecting the cable to the DUT also helps you avoid any imbalance..
  4. Eliminate ground loops. Another way to minimize conducted noise is by eliminating ground loops. The system should have only one connection to ground. In rack systems, where you have multiple ground points, keep the DC distribution path separate from paths that carry other ground currents. If necessary, you can isolate the power supply from ground. The Sorensen XT Series offers isolated outputs that make this easy to do.
  5. Use a bypass capacitor at the load to smooth voltage spikes. If your load rapidly changes the amount of current drawn from the supply, it may cause voltage spikes. Adding a bypass capacitor close to the load will help reduce those spikes.. The capacitor should have a low impedance at the highest testing frequencies.

For more information on reducing noise in your test system, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

Get the Rev Right When Running MIL-STD-704 Test

Written on July 25, 2017 at 1:46 pm, by

As noted in an earlier blog post, the tests you run to ensure that airborne utilization equipment is compatible with an aircraft’s power system are specified in a series of MIL-HDBKs, specifically MIL-HDBK-704-1 through MIL-HDBK-704-8. To run these tests, a sophisticated power source is essential to simulate various power conditions. In addition, you also need whatever equipment is required to monitor the unit under test (UUT) while running the test.

Recognized as a world leader in programmable power, AMETEK Programmable Power has provided test equipment for compliance tests for airborne utilization equipment for decades. Over the years, we’ve updated our systems to cover the latest versions of MIL-STD-704 and to make our test equipment more effective and easier to use. Our MIL-STD-704 test solutions are in use by customers in U.S. and in countries all over the world.

Rev. F doesn’t negate earlier versions

Although the latest version of MIL-STD-704 is rev. F, you may have to run tests that comply with previous versions of the standard. The reason for this is that aircraft platforms tend to have a long life, and the power systems in those aircraft may be designed to comply with an earlier version of MIL-STD-704. When testing the utilization equipment for a particular platform, then, it’s imperative that you know what revision of MIL-STD-704 that the aircraft platform was designed to comply with.

The early versions of MIL-STD-704 specified the requirements for fewer types of power systems than the later revisions. Rev. A, for example, described the requirements for only three aircraft electric power systems:

  • three-phase 115V/400Hz AC,

  • single phase 115V/400Hz AC for devices requiring less than 500VA, and

  • 28V DC.

In rev. B, the authors added requirements for the 270V power system.

In rev. F, there are specifications for seven different power systems. In addition to the four already mentioned, rev. F includes specifications the following aircraft electric power systems:

  • single-phase, 115V/360-800Hz various frequency,

  • three phase 115V/360-800Hz various frequency, and

  • single-phase 115V/60Hz to power commercial, off-the-shelf (COTS) equipment.

Figure 1. Select the MIL-STD-704 version as needed.

Because utilization equipment may have to comply with earlier versions of MIL-STD-704, AMETEK Programmable Power’s test solutions allow users to easily select the appropriate version of the specification when setting up the test. As shown in Figure 1, test engineers and technicians, simply choose the appropriate revision from a drop-down menu.

Figure 2. Select the appropriate power group.

The next step is to choose the type of power that the power source is to supply to the utilization equipment. This is done by selecting one of the power groups as shown in Figure 2.

MIL-HDBK-704-1 through MIL-HDBK-704-8 specify the acronyms used for the seven power groups. They are:

  • SAC (single phase 115V/400Hz),

  • TAC (three phase 115V/400Hz),

  • SVF (single phase 115V various frequency),

  • TVF (three phase 115V various frequency),

  • SXF (single phase 115V/60Hz),

  • HDC (270V DC), and

  • LDC (28V DC).

Once these have been selected, the power source will supply power that simulates the various operating conditions as specified in MIL-STD-704. These include normal, transfer, abnormal, emergency, electric starting and power failure conditions. When subjected to these power conditions, the utilization equipment is expected to operate normally and perform to specifications.

These documents, including MIL-STD-704 (revisions A through F) are available online at EverySpec.Com. For information on how to use AMETEK power sources to run MIL-STD-704, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

Know Your Power Supply Jargon: Ripple

Written on July 14, 2017 at 8:06 am, by

AMETEK Programmable Power DC power supplies convert AC power to DC power. While our supplies are very good at doing this, they’re not perfect. On the output, there will be some small amount of AC still present. This is called ripple.

Minimizing ripple is important because excessive ripple because it can have adverse effects on the systems or circuits that a supply is powering. It can for example, cause measurement errors when a supply is powering instrumentation circuits or cause distortion when power audio circuits.

To see how ripple occurs, let’s take a look at a simple linear power supply. Linear supplies generally use a transformer to convert 120 VAC or 240 VAC mains power to a lower AC voltage. That AC voltage is then rectified to convert the AC to DC. A full wave rectifier will convert the AC voltage to the DC waveform shown as a dashed line in Figure 1.

To smooth that voltage we can put a filter capacitor across the output of the rectifier. It will charge when the rectified voltage is increasing and discharge when the rectified voltage is decreasing, but not discharge to zero. The voltage across the filter capacitor is shown as the orange line in Figure 1. The peak-to-peak value of the AC component of the voltage across the capacitor is the ripple voltage. The addition of a choke and a second capacitor to for a low-pass pi filter will reduce the ripple even more.

Of course, AMETEK Programmable Power supplies use much more sophisticated circuits to filter and regulate the output voltage. Our linear supplies, for example, use semiconductor voltage regulators to nearly eliminate ripple. The Sorensen XT Series, for example, has an output noise and ripple specification of less than 1 mV.

On most AMETEK Programmable Power data sheets, you’ll find noise and ripple combined into a single specification. Noise is any added and unwanted electronic interference, and it’s difficult to really differentiate how much of the unwanted output variation is due to ripple and how much is added noise. In switching power supplies, the measurement is given as a peak-to-peak voltage, indicating how much the output voltage can deviate from the nominal value.

For more information on power supply ripple, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

RS Series high-voltage option eases PV inverter testing

Written on July 14, 2017 at 8:02 am, by

As the number of photovoltaic power-generation systems continue to increase, the requirements for photovoltaic inverters are evolving as well. Conventional electrical characteristics such as over-voltage, over-frequency, anti- islanding intended to verify the inverter’s ability to tolerate power grid fluctuation are changing to meet varying requirements of the modern grid. In addition, the introduction of new requirements for low voltage ride through, high voltage crossing, and reactive power injection mean the inverter must be able to provide appropriate compensation when these grid conditions occur.

To aid in the development and testing of the photovoltaic inverters, you can use powerful bi-directional AC power sources to simulate different power-grid conditions. To perform the required tests, the AC power sources or grid simulators must have a wide output voltage range or multiple output voltage ranges to accommodate the output voltages of different photovoltaic inverters.

Photovoltaic inverters can have output voltages of up to 800 VAC L-L (461 VAC L-N) and when testing high line conditions, the power source may have to output more than 1100 VAC L-L (635 VAC L-N).

When equipped with one of several different high voltage options, AMETEK’s RS Series AC power source can supply the necessary voltages. These options give the RS Series an additional voltage range with built-in hardware that eliminates the need for additional transformers to step up voltages to simulate the power grid. With this option, the RS Series can supply up to 650 VAC L-N (XV650).

HV and XV Options

The XV and HV high voltage options give the RS Series use internal autotransformers that step the voltage up to the desired level. There are several different options available, depending on the desired maximum output voltage, including:

  • HV – 400 VAC L-N, 75 A
  •  XV500 – 500 VAC L-N, 60 A
  • XV600 – 600 VAC L-N, 50 A
  • XV650 – 650 VAC L-N, 46.2 A

With the XV650 option, an RS Series power source can supply up to 1,125 VAC L-L.

HVC and XVC Options

The HVC and XVC options are similar to the HV and XV options, but provide constant power output down to 80% of the maximum output voltage. At 80% of the maximum output voltage, an RS series power source can actually supply 125% of the maximum current supplied by an RS Series power source with an HV or XV high voltage option. See the figure below.

For example, an RS Series power source with the XV650 option has a maximum current output of 46A at 650 VAC. At 80% of maximum, or 520 VAC, the maximum available output current is still just 46A. With the XVC650 option, however, the RS Series power source can supply up to 57 A. The HVC and XVC options include:

  • HVC – 400 VAC L-N, 93.8 A
  • XVC500 – 500 VAC L-N, 75 A
  • XVC600 – 600 VAC L-N, 62.5 A
  • XVC650 – 650 VAC L-N, 57.7 A

Field Installation and Custom Ranges

The HV, XV, HVC, and XVC options can all be installed in the field. Please contact AMETEK Programmable Power to evaluate your upgrade options. AMETEK Programmable Power can also supply custom high-voltage voltages ranges. To inquire about a custom voltage range that is not listed, please contact us at ci.ppd@ametek.com

For information on the RS Series AC/DC power sources or the high voltage options, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

Choose the Right Gauge Wire Size for Your Application

Written on June 8, 2017 at 12:26 pm, by

When installing an AMETEK Programmable Power power source, you must properly size the wires you use to connect the AC input power to the power source and the AC or DC output to the load. Selecting the right size gauge wire will ensure that your power source will operate efficiently and reliably.

The tables below will help you determine the appropriate wire size for both the input and output connections. Table 1 gives minimum recommended gauge wire size for copper wire operating at a maximum of 30° C ambient temperature. The data in this table comes from the National Electrical Code, and is for reference only. Local codes can impose different requirements, so make sure to check them before making a final installation. To handle higher currents, wires can be paralleled; refer to the National Electrical Code for guidelines.

Table 1.

There are two main reasons for choosing the right size wire for the load. The first reason is to ensure that the cable can safely carry the maximum load current without overheating, which may present a fire hazard or cause the insulation to degrade. The second reason is to minimize the IR voltage drop across the cable. Both of these phenomena have a direct effect on the quality of power delivered to and from the power source and corresponding loads.

If the ambient temperature of the installation is greater than 30° C, consider using a larger gauge wire than shown in Table 1. The ability of a wire to carry current, also called its ampacity, decreases as the ambient temperature increases. So, use short cables with a larger gauge wire than shown in Table 1. And, if power cables are to be bundled with other cables, you may have to derate even further, as the operating temperature inside the bundle may be higher than the ambient temperature.

Also, be careful when using published commercial utility wiring codes. These codes are designed for the internal wiring of homes and buildings, and while they do take into account safety factors, such as wiring loss, heat, breakdown insulation, and aging, they allow a voltage drop of 5%. Such a high voltage drop may not be acceptable in your application.

In high performance applications where loads draw high inrush or transient currents, make sure to consider the peak currents that the cables may have to accommodate. These peak currents may be up to five times the RMS current values. An underrated wire gauge adds losses, which alter the inrush characteristics of the application and thus the expected performance.

Table 2 shows the ampacity, resistance per 100 ft, and voltage drop per 100 ft. at the rated current, at an ambient temperature of 20° C. Copper wire has a temperature coefficient of α = 0.00393Ω/°C at t1 = 20°C, so that at an elevated temperature, t2, the resistance would be R2 = R1 (1 + α (t2 – t1)).

Table 2.

The output power cables must be large enough to prevent the line voltage drop (the sum of the voltage drops across both output wires) between the power source and the load from exceeding the remote sense capability of the power source. Calculate the voltage drop using the following formula: Voltage Drop = 2 × distance-in-feet × cable-resistance-per-foot × current.

For more information on right gauge wire for your application, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

Ensure Avionics Reliability with MIL-STD-704 Tests

Written on June 8, 2017 at 12:20 pm, by

To ensure that aircraft electronics and other electrically-powered equipment will operate reliably once in the air, you must test them under extreme power conditions. In the military world, MIL-STD-704 (now up to rev. F), “Aircraft Electric Power Characteristics,” establishes the requirements and characteristics of aircraft electric power. This standard is not only used by the U.S. military and military contractors, but has also been adopted, either directly or indirectly, worldwide. For example, the Chinese standard, GJB 181, Characteristics of aircraft electrical power supplies and requirements for utilization equipment, is largely based on MIL-STD-704.

MIL-STD-704 actually defines the power characteristics of an aircraft electric power system, not the test requirements. Section 5.2, for example, describes AC power characteristics. 5.2.1 says, “AC systems shall provide electrical power using single-phase or three-phase wire-connected grounded neutral systems. The voltage waveform shall be a sine wave with a nominal voltage of 115/200 volts and a nominal frequency of 400 Hz.” It also describe three alternative power systems, including a variable frequency system, a double-voltage system and a single-phase, 60 Hz system. Section 5.2 goes on to describe the phase sequence for three-phase systems, normal operation, abnormal operation, and emergency operation characteristics. A series of tables lists the specifications.

Even though we call the tests performed to ensure that equipment will perform properly on board an aircraft “MIL-STD-704 tests,” the standard does not describe any tests. For guidance on testing, there is a series of handbooks that specify tests for different types of input power. These include:

  • MIL-HDBK-704-1, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics

  • MIL-HDBK-704-2, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, Single Phase, 400 Hz, 115 Volt

  • MIL-HDBK-704-3, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, Three Phase, 400 Hz, 115 Volt

  • MIL-HDBK-704-4, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, Single Phase, Variable Frequency, 115 Volt

  • MIL-HDBK-704-5, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, Three Phase, Variable Frequency, 115 Volt

  • MIL-HDBK-704-6, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, Single Phase, 60 Hz, 115 Volt

  • MIL-HDBK-704-7, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, 270 VDC

  • MIL-HDBK-704-8, Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, 28 VDC

These documents, including MIL-STD-704 (revisions A through F) are available online at EverySpec.Com. For information on how to use AMETEK power sources to run MIL-STD-704, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.

Modern Power Supplies Help Reduce Test Costs

Written on May 24, 2017 at 7:57 am, by

Test costs can add considerably to overall manufacturing costs, especially when extensive testing is required. That’s why it’s important to keep test costs to a minimum. Reduced test costs translate to lower manufacturing costs. Modern power supplies, such as California Instruments’ Asterion Series, have several features that can help you reduce test costs:

Faster command processing times
Because modern power supplies use more sophisticated processors, they can process commands faster than earlier generations of power supplies. Reducing command processing times means reduced test times, and that helps lower test costs.

Command processing times are not often specified for power supplies, but there is a test that you can perform to compare the command processing times of different power supplies. What you do is program a power supply to go from 0 V to some particular value and measure the time from the point at which you send the command to the time the power supply voltage reaches the target value.

While this test is not measuring just the command processing time, it will allow you to compare the performance of several different power supplies. Perform a similar test for other commands and you can get a better feel for how the power supply will perform in your application.

Built-in measurement capabilities
Built-in measurement capabilities can also help you shave test times. Communicating with a single instrument, such as a power supply with measurement capabilities, instead of multiple instruments, such as a power supply and system DMM, can save overall test time. An added benefit of using a power source with measurement capability is that the test system design is simpler, and because you’re using fewer instruments and less cabling, the test system should be more reliable, too.

Advanced software commands
Many tests require a power supply to step through a series of different outputs during the test. While it is possible to program each of these steps individually from the control computer, a much more efficient and time-saving way is by using what’s commonly called the list function.

Too see how this works, refer to Figure 1. It shows a typical series of output voltages that you might generate using the list function. It includes three different AC voltage steps: 160 volts for 33 milliseconds, 120 volts for 83 ms, and 80 volts for 150 ms, separated by three intervals of zero volts for 67 ms. The list specifies the pulses as three voltage points (point 0, 2, and 4), each with its corresponding dwell points. The intervals are three zero-voltage points (point 1, 3, and 5) of equal time duration. In addition to the different output voltages, you can also set a count parameter, which specifies how many times the power supply will output the sequence.

Figure 1.

The point here is that you set up this sequence with a single command instead of a series of commands, and by doing so, you save test time.

These are just three ways that modern power supplies help you reduce test costs. For more information on how AMETEK power supplies help you reduce test, contact AMETEK Programmable Power. You can send an e-mail to sales.ppd@ametek.com or phone 800-733-5427.