Flexible power supply allows versatile testing

A new switch mode power supply has been specially configured to assist pre-compliance electrical testing. REO's 'Platypus' has been given its name, according to the company's John Symonds, because of its versatility and adaptability. Stepless adjustment of both voltage (0 to 300V) and frequency (15 to 150Hz) is provided either by front panel mounted potentiometers or by digital touch panel. The units currently available deliver up to 10A, although a 16A model is being designed, as are units capable of producing 8 to 300Hz, and eventually, 400Hz for testing aerospace devices and systems. Like all switch mode power supplies, it chops a DC source to create a sine wave. This is of good quality on a resistive load, but includes some distortion on inductive loads. Active filtering is included to reduce mains harmonics, a major problem with switch mode power supplies in the past. Communication is via an RS232 interface. Applications include testing for three phase unbalance to EN61000-4-27, using three units, power frequency variation to EN61000-4-28, and under and over voltage testing. Other possible applications include online batch testing of voltage relays, current trips, circuit breakers and relays. The unit can be used in voltage, current or power regulation mode. Panel displays include an analogue ammeter, voltmeter and LED digital display. The unit is protected by three line fuses and is short circuit proofed. In addition to English, it can be programmed in German and French. REO (UK)