Programmable AC Electronic Load – 63800


Chroma 63800 AC Electronic Loads can simulate a variety of load conditions under high crest factor and varying power factors with real time compensation even when the voltage waveform is distorted. This unique feature provides real world simulation capabilities and prevents overstressing the instrument resulting in reliable and unbiased test results.

Key Features

  • Datasheet
  • Power Rating:1800W/3600W/4500W
  • Voltage Range: 50V – 350Vrms
  • Current Range: Up to 45Arms
  • Peak Current: Up to 135A
  • Frequency Range: 45 to 440Hz, DC
  • Crest Factor Range: 1.414 to 5.0
  • Standard GPIB and RS232 interfaces
  • Parallel units for higher power or synchronize for three phase operation
  • Maximum paralleled power: 22.5KW single phase / 67.5KW three phase


The 63800’s state of the art design uses DSP technology to simulate non-linear rectified loads with its unique RLC operation mode. This mode improves stability by detecting the impedance of the UUT and dynamically adjusting the load’s control bandwidth to ensure system stability.

Available comprehensive measurements allow users to monitor the output performance of the UUT. Additionally, voltage & current signals can be routed to an oscilloscope through built in analog outputs. The instrument’s standard GPIB/RS232 interface provides remote control & monitoring for system integration. Built-in digital outputs may also be used to control external relays for short circuit (crowbar) testing.

Chroma’s 63800 Loads feature fan speed control ensuring low acoustic noise. The diagnosis/protection functions include self diagnosis routines and protection against overpower, over-current, over-voltage and overtemperature scenarios.

Complete AC & DC Electronic Load Simulations

Chroma’s 63800 AC & DC Electronic Load is designed for both AC & DC Load Simulations. Illustrated below are the various load modes which are available:

AC & DC Load Modes


AC Electronic Load Simulation

The Model 63800 AC & DC Electronic Load provides two unique operating modes for AC load simulation; (1) Constant Load Mode and (2) Rectified AC Load Mode. Each are described below.


Constant Load Modes

The Constant Load Modes allow users to set the following operating modes: CC, CR and CP mode. The CC and CP modes in this category allows users to program PF, CF, or both. For CR mode the PF is always set to 1. The power factor range is limited based on crest factor programmed (Shown as Figure 1). If the programmed PF is positive then the current will lead the voltage waveform. When PF is set negative, the current will lag the voltage waveform. (See below)

AC Electronic Load Constant Load Modes
Crest Factor vs. Power Factor Control Range

Figure 1: Crest Factor vs. Power Factor Control Range; CFI = I peak / I rms; PF = True power / Apparent power

Rectified AC Electronic Load Modes

The 63800 AC & DC Electronic Load provides unique capability to simulate non-linear rectified loads for a wide range of testing applications. There are three load modes available for rectified load simulations: RLC, CP and Inrush Current.

Figure 2 shows the typical model of a rectified input. Under RLC mode, users can set the RLC values to 100% and simulate the behavior of the actual UUT. Figure 3 & 4 compares the voltage and loading waveforms between the actual RLC built circuit and the simulated rectified circuit by using Chroma’s RLC load mode. The waveform obtained under CC mode with the same loading crest factor shown in Figure 5.

AC Electronic Load Rectified Circuit

Figure 2: Typical Rectified Circuit

For inrush current simulation (See Figure 6), the 63800 has an Inrush Current mode that allows the user to set different inrush current amplitude and voltage phase angle where the inrush current started.

voltage and loading waveforms voltage and loading waveforms CC Mode Inrush Current Simulation
Figure 3 Figure 4 Figure 5 Figure 6


DC Load Simulation

Chroma’s 63800 DC load simulation includes four load modes: constant current, constant resistance, constant voltage and constant power as depicted below. CC, CR, CP mode can be used for regulated voltage power supply testing. For battery charger, CV mode may help to check its current regulation. Many inverter designs, although its input is DC, show an input current and will show rectified pattern. This unique load mode makes the Chroma 63800 load ideal for Fuel Cell, PV module/array and Battery testing.


Comprehensive Measurements

Chroma’s 63800 Series AC & DC Electronic Loads include built-in 16-bits precision measurement circuits to measure the steady-state and transient responses for true RMS voltage, true RMS current, true power(P), apparent power(S), reactive power(Q), crest factor, power factor, THDv and peak repetitive current. In additional to these discrete measurements, two analog outputs, one for voltage and one for current, are provided as a convenient means of monitoring these signals via an external oscilloscope.


Timing Measurement

Timing parameters are critical to many products such as UPS’s Breakers and Fuses. The 63800 AC & DC Load also includes a unique timing and measurement function to measure the trip time of fuses & circuit breakers or the transfer time for UPS’s (Off-Line).

Timing Parameters

Figure 7: Transfer time for Off-Line UPS


Automatic Bandwidth Adjustment (ABA)

When the UUT, such as one shown in Figure 8, has a higher output impedance, the current waveform will not be stable without ABA. In most cases, the loading current will be oscillating and spoil the test.

Fixed Bandwidth

Figure 8: Fixed Bandwidth

With ABA

Figure 9: With ABA


Note 1: A test current will be programmed prior the actual loading defined by user for impedance detection.


Parallel / 3-Phase Control

The 63800 series provides parallel and 3-phase functions for high power and three phase applications. All the models within the 63800 series can be used together for both parallel and 3-phase functions as well as paralleled AC Load units in a 3-phase configuration, providing excellent flexibility and cost savings for the 63800 series AC load.

 Parallel connection

Figure 10: Parallel connection

 Parallel/3-Phase Y connection

Figure 11: Parallel/3-Phase Y connection

 Parallel/3-Phase Y connection

Figure 12: Parallel/3-Phase Delta connection


Auto Power Factor Correction

Setting the power factor is one of the major features to the 63800. The power factor is defined as:

Power Factor

Since PF is a function of real time voltage and current, traditional AC load designs assume the voltage waveform to be sinusoidal all the time, as seen Figure 13. This is not realistic because the voltage waveform may be distorted after the load is applied shown in Figure 14.

Voltage Waveform

Figure 13

Voltage Waveform

Figure 14

AC Electronic Load soft panel

Easy to use soft panels are available for the 63800 to allow monitoring, configuration and reporting from a PC. Contact your sales representative for more information.

See more about our software

Model Description
63802 Programmable AC Electronic Load 1800W/18A/350V
63803 Programmable AC Electronic Load 3600W/36A/350V
63804 Programmable AC Electronic Load 4500W/45A/350V
A638001 Rack Mount Kit [63802]
A638002 Rack Mount Kit [63803/63804]
10604 SoftPanel KIT [63800]
8545-01 Cable Kit with Terminal Resistors, 3 phase sync/Parallel Cable

User Manuals

Manuals - 63800 Series

One time registration required in order to download documents. Register or login to continue. 12.50 MB 1886 downloads

User Manuals for 63800 Programmable AC Electronic Loads. Available documents are: Hardware User Manual 3 Phase Parallel Setting Softpanel User Manual All files in PDF format. ...


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Application Notes

    How To Buy

    Three efficient ways to get pricing and/or more information regarding this instrument:

    Electronically: Please complete this form and one of our sales engineers will respond same day or next business day if after hours. Requests from this form are quoted directly from Chroma.

    By phone: Call us at 949-600-6400, let the operator know where you are located, and you’ll be routed to your regional sales engineer.

    By chat: Feel free to use the Chat line located at the bottom right of this page. The chat operator will take your information and route it to your regional sales engineer.


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    Lead time

    Most of our instruments are inventoried and ready to ship. If we are currently out of stock – and due to demand we can be - lead times are typically 4-8 weeks depending on the instrument’s power rating.
















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