Paralleled LMX Series | Pacific Power Source

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Paralleled LMX Series

Take control of your AC power.

The LMX Series is a family of High Performance Linear AC Power Sources covering the power range from 500 VA to 30kVA. The 4000VA to 6000VA LMX models can be paralleled when configured with the -PB (Parallel Bus) option to increase overall output current and power. Up to five LMX units can be configured for parallel operation.
360LMX AC Power Source

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The versatility of the -PB (Parallel Bus) option for the 140/160/345/360LMX and 140/160/345/360LMXT AC Power Sources provides the user a wide variety of options using the building block approach to a higher capacity AC Power Source. Each paralleled group of LMX AC Power Sources requires one ‘Master’ unit (front panel controller). The following tables provide examples of the many different configurations possible with each of the LMX Series AC power source models.

System Power up to 30 kVA

Configure your system and decide the level of flexibility as per your current and future requirements. The -PB (Paralleling Bus) option for the models 140, 160345, 360LMX and 140, 160345, 360LMXT describes a multi-cabinet AC Power Source which can be expanded up to 5 chassis, to reach system power levels up to 30 kVA. Addition or deletion of chassis is easily performed by the user in the field. The system may consist of one master unit and any combination of 4 additional units which can be either Master/Aux selectable or dedicated Auxiliary units. One Master unit is required per system.

Parallelable LMX Models

Single Phase Parallel Models

Model Power (VA) Form Output Volts-Max (VRMS) Function Height
Direct 1.5:1 2.0:1 2.5:1
140LMX-PB 4000 1Ø/2Ø 135/270 Master 8U
140LMX-AUX 4000 1Ø/2Ø 135/270 Aux 8U
140LMXT-PB 4000 1Ø/2Ø 135/270 202/404 270/540 338/600 Master 11U
140LMXT-AUX 4000 1Ø/2Ø 135/270 202/404 270/540 338/600 Aux 11U
160LMX-PB 6000 1Ø/2Ø 135/270 Master 8U
160LMX-AUX 6000 1Ø/2Ø 135/270 Aux 8U
160LMXT-PB 6000 1Ø/2Ø 135/270 202/404 270/540 338/600 Master 11U
160LMXT-AUX 6000 1Ø/2Ø 135/270 202/404 270/540 338/600 Aux 11U

Three Phase Parallel Models

Model Power (VA) Form Output Volts-Max (VRMS) Function Height
Direct 1.5:1 2.0:1 2.5:1
Master 8U
Aux 8U
Master 11U
345LMXT-AUX 4500
Master 8U
Aux 8U
Master 11U
360LMXT-AUX 6000

Key Features

Key Features Provide Application Versatility

  • USB, LAN (LXI), IEEE-488.2 and RS-232C with SCPI compatibility
  • Compatible with PPSC Studio graphical user interface
  • LabVIEW for Windows®/LabWindows® drivers
  • Waveform Creation by Harmonic Synthesis
  • Waveform Capture (Voltage and Current)
  • Harmonic Analysis (Voltage and Current)
  • Metering of RMS and Peak Values
  • Continuous Self Calibration (CSC)
  • Line Sync
  • 6:1 Peak Current Capability
  • Low Impedance for EN61000-3-2, 3 Testing
  • Programmable Output Impedance
  • Up to 0-300 VAC Direct Coupled Out
  • 1 Phase / 3 Phase Switch Selectable
  • 15-5000 Hz Full Power Bandwidth
  • Power Levels from 500 VA to 6 kVA standard; 30kVA optional
  • Externally Referenced Meter Calibration
  • CE Safety & EMC and NTRL Safety Mark

Design Provides Total Control of AC Power

  • All LMX Series power source models are equipped with our new digital Real-Time programmable Controller.
  • Single phase power source models may be controlled to operate on either a 0-135 VAC range or a 0-270 VAC range. Three phase models are additionally switchable to 3ø/1ø output power form.
  • Total control of the output power form and the selection of either the direct output or the optional transformer output is available from the front panel or the bus.
  • All operating functions may be controlled from either the front panel or from a remote USB, LAN (LXI compliant), RS-232 or IEEE 488.2/ SCPI BUS. LabVIEW for Windows® and LabWindows® Instrument Drivers are available.
  • The LMX controller supports a browser interface that allows control of the power source over LAN or USB using a web browser on PC, laptop or smartphone.

Special LMX Series Operating Features

Continuous Self Calibration

Provides for exceptional accuracy of the AC output Voltage. When enabled, accuracy improves to ±0.03% referenced to the power source internal voltmeter.

Programmable Dynamic Output Impedance

Programmable Output Impedance provides the operator with dynamic control over the output impedance of the AC Power Source. Using the output current term as conditioned feedback signal to the output voltage circuits, positive or negative impedance may be programmed. The purpose of this control is to simulate the effects of or compensate for high peak current, distribution, or transformer losses of up to ±10% of the output voltage.

This feature creates positive, negative, or zero output impedance (Zo).

  • Compensates for line distribution or transformer losses.
  • Simulates a soft power line for product testing. Compensation range is ±10% of the output voltage.
Waveform Library

Up to 200 different waveforms can be stored in the waveform library for execution as part of a steady state program or for substitution in any output phase as part of a transient test program. Memory location #1 is a non-editable high resolution sine wave. All other locations are editable and can be substituted in any output phase. An unlimited number of waveforms may be stored on the computer.

Waveform Edit

Provides the ability to modify a stored waveform by specifying the waveform amplitude desired at each specific phase angle.

Waveform Analysis

Provides both a graphic and numeric display of the harmonic structure of a voltage or current waveform. Data presented includes the magnitude of each harmonic in %, the total harmonic distortion, and the odd and even harmonic distortion in %.

Waveform Synthesis

Provides the ability to quickly create virtually any AC Test Waveform that may be required by building it out of harmonics. The process is as simple as keying in the harmonic multiple, the amplitude, and the phase angle for each desired harmonic up through the 51st.

Time Based Transients

Provide the ability to create and execute on command, transients that occur linearly over a specified time segment to modify output voltage or frequency.

Cycle Based Transients

Provide the ability to create and execute, on command, transients that substitute a selected waveform in the output for 1 to 100 cycles.


AC Test Power

The LMX Series Power Source is equipped with multiple Digital Signal Processors (DSPs) to create a fully integrated test system. It supplies a variety of power conditions to the device under test and meters/analyzes all output performance parameters.

Frequency/Voltage Conversion

The LMX Series is an excellent source of stable AC voltage over the frequency range of 15 to  5,000 Hz. The output frequency is quartz-crystal stabilized. Output voltages up to 600 VAC are provided.

Phase Conversion

With the ability to provide single and three-phase outputs, the LMX Series is the perfect choice to provide 1 Phase to 3 Phase or 3 Phase to 1 Phase conversion.

Dual Range Output Magnetics Options

LMX Series Power Sources can be equipped with output transformers to provide an alternate output voltage range. Selection of direct or transformer coupled range is performed by the controller via front panel or bus command. The standard frequency range for transformer coupled outputs is 45 to 5,000 Hz. Standard output ratios are 1.5:1, 2.0:1, and 2.5:1. Transformer outputs are supplied internally or externally via a Magnetics Module as listed in the above table. Consult the factory for additional information regarding special output ranges not listed above.


Power Source Specifications

Output Frequency:
15 to 5000 Hz. Full Power

Line Regulation:
0.1% max for a 10% line change

Load Regulation:
0.25% 15 to 2000 Hz. 0.5% 2000 to 5000 Hz. Can be improved to less than 0.03% with CSC engaged

Output Distortion:
0.1% THD from 15 to 1000 Hz 0.25% THD from 1000 to 5000 Hz

Ripple and Noise:
-72 dB

Response Time:
5µsec. typical to a step load change. Small signal band-width is 5 Hz. to 50 kHz, typical.

Mechanical Specifications

All models are designed for operation in 19 inch equipment racks. Models above 1800 VA have side handles for ease of handling.

Standard 19 inch rack. Slide rails are available as an option for all models.

See model table above for panel height.

Will not exceed 24 inches from the front panel to the rear of the chassis, including connectors, handles and cabling.

Forced air, front or side intakes, rear exhaust with auto fan speed control for low acoustic noise operation.

LMX Controller Specifications

The LMX controller is essentially a single or three phase AC arbitrary waveform generator and Precision AC metering system. The waveform for each phase may be independently selected and may be independently varied in amplitude and phase angle with respect to phase A (3 phase systems).

The metering function samples the output volts and amps at 1024 samples per measurement using a 16 bit A/D converter. This technique provides exceptional metering accuracy and resolution and delivers a high-fidelity waveform back to a host computer for analysis.

The LMX includes LAN, USB, IEEE 488.2 and RS232 interfaces using SCPI commands.

15.00 to 5000 Hz ±0.01%

Voltage (Direct):
Programmable, 0-VMAX, in 0.1 volt steps (see table).

Phase Angle:
Phase Angle (f) of Phases B and C relative to Phase A is programmable from 0-359° in 1° increments ± 0.5°.

Current Limit:
Current limit is programmable from 0 to I peak maximum of the power source. Accuracy is ± 0.5%, resolution ±10mA.

Waveform Library:
Stores up to 200 waveforms that can be edited and executed in any manner and in any output phase.

Range: 0-340 volts L-N, 0-600 volts L-L
Resolution: 0.10VAC to front panel, 0.001VAC to remote interface
Accuracy: ±0.1% of range

Range: 100% of system current rating
Resolution: 0.01 Arms
Accuracy: ± (0.5% + f (kHz) * 0.5%) F.S.

Power Meter:
Range: Based on ammeter range
Resolution: 1 W, 1 VA (front panel)
or 0.1 W, 0.1 VA remote control
Accuracy: ± 0.75% of Full Scale

Power Factor & Crest Factor:
Calculated and displayed to four significant digits.

Expanding the AC Power Source into an Automated Test System

Pacific’s line of Smartsource® AC Power Sources enable the engineer to simply automate his testing by using Lab VIEW for Windows® or LabWindows®. An extensive list of Virtual Instruments (VIs) are offered for Pacific’s LMX Series Power Sources.


Magnetics Module

Addition or deletion of cabinets is easily performed by the user in field.The standard LMX-Series features, such as automatic output form selection, extensive output metering, etc. remain intact. Note that only identical models may be paralleled with each. That is, only 345LMX chassis may be paralleled with other 345LMX chassis and likewise for the Model 140 and 360LMX. Paralleling of a 140LMX or 345LMX chassis with a 360LMX chassis is not allowed.

Brochures & Manuals

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