Two pole voltage testers generally have a self testing function to check the unit is working and does not have exhausted batteries. This test does not necessarily indicate the instrument will safely show a voltage measurement, particularly voltages in excess of 50 volts. Two pole voltage testers are recommended to be tested with a known live voltage source prior to making a voltage measurement on a circuit.

The Megger MPU690 proving unit provides an alternative portable battery operated voltage source that can verify the correct functioning of a voltage tester. The device safely generates a range of voltages from 50 to 690 volts in five steps. At switch on, the unit initially generates 690 volts then after a short period, slowly ramps down through each voltage step until the device switches off. The individual voltage steps are indicated by an LED with a power indicator LED that also indicates an exhausted battery. The MPU690 features automatic power on when voltage tester probes are inserted into the output terminals, generating a 50 Hz output voltage which simulates the AC mains supply.

Application

The generous output power rating and the spacing of the output terminals allows the MPU690 to verify the correct operation of voltage indicators that utilize a lamp for operation. Although the unit has a high output the unit has exceptionally good battery life. The rugged case of the MPU690 features a magnetic base for convenient use. N.B. The MPU690 is not recommended for use with multimeters.