Used AC Power Supplies for Sale

A programmable AC power supply (also called an AC source) outputs a precise, adjustable AC voltage and frequency under software control — unlike a variac or isolation transformer which just attenuate the mains. You need one when you must test a product at a specific voltage and frequency combination (e.g. 100 V/50 Hz Japanese mains, 230 V/60 Hz abnormal condition, or 400 Hz aircraft power), simulate brownout and surge events, or make repeatable IEC 61000-4-11 voltage dip tests. Standard benches testing US-market electronics only rarely need one; labs doing international compliance testing, avionics, or power supply characterization use them constantly.

A single-phase AC source outputs one AC voltage between line and neutral — it is what you need for testing consumer electronics, single-phase power supplies, and most bench-level AC testing. A three-phase AC source outputs three voltage phases 120 degrees apart and is required for testing three-phase motors, three-phase power supplies, variable frequency drives, and industrial equipment that runs on three-phase power. Three-phase sources are significantly larger and more expensive. Most used AC sources on the market — Keysight AC6800 series, Chroma 61500 — are single-phase. Three-phase units like the Pacific Power 345-AMX are available but less common.

The AC6801B (500 VA) and AC6802B (1000 VA) are the most common Keysight programmable AC sources on the used market. The key check is output voltage accuracy — measure actual output with a true-RMS DMM at several set points (100 V, 120 V, 230 V) and compare against the 0.1% typical spec. The second check is frequency accuracy; use a frequency counter at the output terminals. The most common fault on these units is a degraded output amplifier that causes increased output THD — you will see this as waveform distortion on a scope at the output. We verify output voltage, frequency, and waveform quality on every AC source before listing.

Many programmable AC sources can simulate voltage dips and short interruptions, but whether the specific unit meets IEC 61000-4-11 requirements depends on how fast the output can transition and the coupling/decoupling network used. Keysight AC6800 series units support voltage step changes but the transition time specification needs to be verified against the IEC standard requirement for the test class. For formal compliance testing, you need either a purpose-built immunity test system or an AC source that explicitly certifies IEC 61000-4-11 capability. For pre-compliance screening, most programmable AC sources are adequate.

The Chroma 61501 is a 500 VA single-phase programmable AC source with a voltage range of 0–300 V AC and 0–424 V DC, frequency range 15–1000 Hz, and output current of 4.5 A RMS at 100 V. The 61511 is a 1000 VA variant with 9 A RMS output current — the right choice for testing higher-power devices where the 61501 would current-limit under load. Both support GPIB and RS-232. The most common used market issue on the 61501 is a failed output relay that prevents output enable, which is a straightforward repair.

Yes. Programmable AC sources are calibration instruments for AC voltage and frequency — the output accuracy directly affects any AC compliance test result or power measurement you record. Most manufacturers recommend annual calibration. Calibration verifies output voltage accuracy at multiple set points and frequencies, output frequency accuracy, and THD. We offer NIST-traceable calibration for Keysight AC6800 series and Chroma 615xx series units. Units listed with a current calibration certificate are clearly noted; units without are listed as uncalibrated with the condition reflected in the price.