Front Panel Control
- Multi-mode AC Electronic Load Flexible solution for a wide range of AC power test applications
- 3000 Watt Power Dissipation Leader / Follower configurations for higher power and multi phase applications
- 50 to 350 V, 45 Hz to 440 Hz Commercial, Military and Avionics applications
- Programmable Crest & Power Factor Test AC power products for
- Built-in Measurements Eliminates the need for additional test equipment in bench or ATE applications
- Remote Control IEEE-488 and RS232C Interface for automated test applications
The AC load can be operated from an easy to use, menu driven front panel. Product tests can be performed quickly in an R&D setting by punching up specific load conditions on the front panel and reading the measurement screen of the 3091LD. This fast interactive front panel control mode can be used during a product's early development cycle to isolate potential performance problems before the product leaves the engineering lab.
The 3091LD can be deployed in ATE test stations using either IEEE-488 or RS232C remote control. The industry standard SCPI (Standard Commands for Programmable Instrumentation) protocol is used and instrument drivers are available to ease test software development. The built-in metering functions of the 3091LD AC load can be used to eliminate the need for additional test equipment such as meters, power analyzers and oscilloscopes. This and the reduced size of the 3091LD compared to passive load banks, represents a savings in both cost and rack space.
Each 3091LD is capable of dissipating 3000 W of single phase AC power. For higher power or three phase applications, a 3091LD leader unit can be combined with one or more follower units. The leader 3091LD unit provides the required consolidated measurements so the test system controller - or the operator - need only interface to the leader unit, regardless of the specific configuration. Single, split or three phase configurations can be software configured from the leader 3091LD.
Measurement and Analysis
The 3091LD can be used to emulate a wide variety of AC load conditions to support real-world testing and evaluation of UPS and AC source products. Specifically, the following modes can be selected:
||This mode effectively emulates constant power loads such as switching power supplies.
||Emulates a conventional resistive load or power resistor. A programmable range from 2.5 Ohms to 1000 Ohms covers a wide range of applications. This mode can be used to replace conventional resistive load banks.
||Provides a constant current load. This mode may be used to simulate both linear (resistive) and nonlinear (active) loads for voltage regulation testing.
||This mode emulates a shunt regulator load and may be used to test current source products.
||Test the short circuit protection mode of the EUT by providing a short condition. The 3001LD can handle surge currents of up to 300 Amps for up to 50 msec and sustained currents of 30 Amps in this mode of operation. The low voltage cut-off of the load can be programmed from 50 Volts up
All AC load modes are easily set from the front panel using a menu-driven user interface. The large LCD screen is used to display setup information as well as measurement data. Measurements include volt RMS, volt peak, current RMS, current peak, crest factor, true power, apparent power, power factor and frequency. Both voltage and current waveforms at the load input terminals can be digitized and displayed on the front panel graphical LCD. This allows EUT output behavior to be analyzed quickly without the need to hook up additional test equipment. A Windows graphical user interface (GUI) is provided to expand the measurement and display capabilities of the 3091LD. The GUI can be used to save and print test results for report purposes.
Crest Factor and Power Factor control
When operating in constant current or constant power mode, the 3091LD supports crest factor control by narrowing the conduction angle of the current waveform in order to match the requested crest factor. Thus, the peak current is increased while retaining the RMS current level. While the apparent power remains constant, the true power decreases. This results in a reduced true power factor. Consequently, as crest factor is increased, the true power factor automatically decreases. The load further controls power factor by shifting the current with respect to the input voltage (displacement power factor). Both leading and lagging power factor control is available. A phase shift of the current is only possible if the crest factor is higher than 1.414. Thus, crest factor and power factor control ranges are coupled as shown in the graph to the right.
Instrument Control Software
The large LCD screen is used to display setup information as well as measurement data. Measurements include volt RMS, volt peak, current RMS, current peak, crest factor, true power, apparent power, power factor and frequency. Both voltage and current waveforms at the load input terminals can be digitized and displayed on the front panel graphical LCD. This allows EUT output behavior to be analyzed quickly without the need to hook up additional test equipment. A Windows graphical user interface (GUI) is provided to expand the measurement and display capabilities of the 3091LD. The ICS can be used to save and print test results for report purposes.