Housed in a rugged compact case that makes it ideal for use in the field, the MIT30 high voltage insulation tester, available from Megger offers continuously variable output voltage from 0 to 30 kV with test currents up to 330 µA. The maximum output voltage and current can be achieved simultaneously, which allows fast charging of capacitive test pieces, thereby significantly reducing testing times.
Typical applications of this high voltage insulation tester instrument include acceptance and maintenance testing of switchgear and transformers, as well as the testing of spark gaps used in radar installations, EMP suppression systems, and to provide back-up over-voltage protection for klystrons and BWOs (backward wave oscillators). Digital readouts display the test voltage and current continuously during a test, with an accuracy of 1.5%. Resolution for the voltage readout is 10 V, and for the current readout 100 nA.
To further enhance testing accuracy, the MIT30 insulation tester incorporates a current guard circuit that allows the influence of external effects, such as surface leakage, to be minimised. To protect the test piece from flashovers and possible damage, the MIT30 insultaion tester features a user adjustable current trip that can be set between 0 and 360 µA. Also incorporated is an ionisation detector that gives an audible indication of any electrical discharges that occur while the test is in progress.
The ergonomic design of the MIT30 insulation tester ensures ease of use, and reduces the amount of training needed to familiarise new users with the instrument. Operator safety is enhanced by features that include a zero-start interlock, a cable interlock with a bright LED indicator and outputs that are protected for both short- and open-circuit conditions. Also incorporated as standard is a heavy-duty discharge assembly that rapidly discharges not only the power supply but also the test piece, thereby minimising the risk of shock hazards.
Weighing just 10 kg, and with an IP67 ingress protection rating when closed (IP52 when in use), Megger’s MIT30 high-voltage low-current insulation tester operates from AC supplies from 85 V to 264 V with frequencies from 47 Hz to 440 Hz. Operation from DC supplies in the range 110 V to 350 V is also supported.