Programmable AC & DC Electronic Loads Model 63800 Series

Zhimao's latest 63800 series AC/DC electronic loads are designed for testing of Uninterruptible Power Systems (UPS), Off-Grid Inverters, Automotive Inverters, AC Power Supplies, and other power components such as switches, circuit breakers, fuses and connectors.

The 63800 Series can simulate loads at high peak factors, even when the voltage waveform is distorted, and instantly compensate for power factor. This feature makes the ability to simulate loads more realistic and prevents voltage overstress, resulting in more reliable and fairer test results.

The 63800 series uses DSP technology to develop a unique RLC operation mode to simulate non-linear rectified loads. In addition, the impedance of the object to be measured can be detected to enhance stability, and the bandwidth can be dynamically adjusted to ensure system stability.

The 63800 series has a unique time measurement feature that allows users to measure critical time parameters such as battery discharge time, fuse blowing time, circuit breaker tripping time, and UPS changeover time.

In terms of measurement, the 63800 series provides users with a wide range of output performance for monitoring the object to be measured. In addition, voltages and currents can be monitored by the built-in analog output signals via BNC cable to an oscilloscope. The GPIB and RS232 interfaces provide remote control and monitoring functions for system integration.

The 63800 series has a fan speed control function that adjusts the air speed with the pulling power to keep the noise as low as possible during use. Self-diagnostics are also available to ensure that normal conditions are maintained during routine power-ups. Protection alarms include over-power, over-current, over-voltage and over-temperature protection.

The 63800 series AC/DC electronic loads are designed to provide both AC and DC load simulation for use. The following tree diagram shows the various load modes available.

The 63800 Series AC/DC electronic loads offer two unique modes of operation for AC load simulation testing: general load mode and rectified load mode. They are described below:

General Load Mode

The general load mode operation modes are Constant Current, Constant Resistance and Constant Power modes. In constant current and constant power operation modes, the user can program the power factor (PF) or peak factor (CF) or both. In constant resistance operation, the PF value is constant at 1. The range of PF values is limited by the set CF value (as shown in Figure 1). In addition, in the definition of the 63800 series, a positive PF setting indicates that the current is ahead of the voltage; conversely, a negative PF setting indicates that the current is behind the voltage. (See figure below)

As shown in Fig. 1, when the input voltage is sinusoidal and CF=1.414, then the PF can only be equal to 1. However, when CF=2, then the acceptable range of the PF is 0.608~0.85 ; when CF=3, the PF can be set in the range of 0.211~0.6. Therefore, higher CF will have a larger range of PF setting.

Rectifier Load Mode

The 63800 Series AC/DC electronic loads have a unique load pulling capability for a wide range of applications to simulate non-linear rectifier load tests. Three modes are available for rectifier load simulation - RLC, Constant Power (CP) and Inrush Current.

▲ Figure 2: Typical bridge rectifier line

Figure 2 shows a typical circuit of a bridge rectifier. In RLC mode, the user can set the RLC value to simulate the behavior of the actual object to be measured by the 100%. Figures 3 & 4 show the actual passive load (resistance, inductance, capacitance) and the measurement using RLC load mode respectively. Figure 5 shows the waveforms obtained in constant current mode.

▲ Figure 3: Actual RLC line

▲ Figure 4: Simulation of RLC mode

▲ Figure 5: Constant Current Mode

▲ Figure 6: Inrush Current Mode

In order to simulate the inrush current (as shown in Figure 6), the 63800 series has an inrush current mode that allows the user to set different starting angles for the inrush current, which saves the user a lot of time in measuring the inrush current.

The 63800 DC load simulation includes four load modes: constant current, constant resistance, constant voltage and constant power modes, as described below.

Constant Current, Constant Resistance and Constant Power modes are available for power supply testing. In the case of battery chargers, Constant Voltage mode can be used to help check current regulation, and the 63800 Series' DC Rectifier Load Mode can be used to test the first stage A/D of a UPS. This unique DC Rectifier Load Mode makes the 63800 an ideal load for UPS, Fuel Cells, PV Modules/Arrays, and Battery testing.

The 63800 series AC/DC electronic loads have built-in 16-bit precision measurement circuitry to measure steady state and transient response, and measure a total of: Root Mean Square Value (Vrms) of voltage, Root Mean Square Value (Arms) of current, Real Power (P), Apparent Power (S), Void Power (Q), Peak Factor (CF), Power Factor (PF), Voltage Total Harmonic Distortion (THDv) and Positive and Negative Peak current (±Ipeak). In addition to these measurements, there are two analog outputs, voltage and current, which are convenient for users to monitor the voltage and current waveforms through the oscilloscope.

time measurement

Time measurement is important for many products such as UPS, circuit breakers, and fuses, etc. The 63800 Series AC/DC loads also offer a unique time measurement function to measure the trip time of fuses and circuit breakers, or the transfer time of an off-line UPS.

▲ Figure 7: Off-Line UPS Conversion Time

When the object to be tested has a large output impedance, such as a generator, the current waveform will be more unstable without the automatic bandwidth adjustment function, as shown in Figure 8. In most cases, the load current will oscillate and affect the accuracy of the test results.

▲ Figure 8: Fixed Bandwidth	▲ Figure 9: Automatic Bandwidth Adjustment
Note 1: Before the actual pulling load, a test current will be pulled to detect the impedance of the object to be measured.

The 63800 series provides multiple parallel, three-phase and parallel three-phase functions, allowing users to perform higher power or three-phase AC power testing applications. The different models of the 63800 series can also be connected in parallel or three-phase with each other, which allows more flexible and elastic use of the 63800 series AC electronic loads to save costs.

▲ Figure 10: Parallel Connection Method

▲ Figure 11: Parallel three-phase Y connection

▲ Figure 12: Parallel three-phase △ connection