MJ159

• Guard terminal to eliminate surface leakage current • Voltage indicating range • Portable tester • No scale multipliers • Multiple test voltages for spot and step voltage testing • Large, easy-to-read scale

The MJ159 insulation resistance tester provides excellent test voltage regulation and is the ideal instrument when high ranges are needed for measuring insulation resistance. It also has an external guard terminal to eliminate surface leakage current from the measurement.

The instrument generates a regulated DC high voltage and use low-zero-drift, high-accuracy circuits, with high current sensitivity. Designed for portability, it is enclosed in a moulded, impact-resistance, flame-retardant case that is made with ABS plastic with a fold down carrying handle.

The MJ159 is operated by a low voltage, hand-cranked generator that has been designed to be easy to turn even under full load conditions. The low voltage generator is connected to an electronic inverter to provide a very stable test voltage. Accuracy of measurement is unaffected by variations in the generator cranking speed and the test voltage is maintained at its rated value. The MJ159 has four selectable test voltages of 100, 250, 500, and 1000 V DC. It measures insulation resistance up to 2000 MΩ, and an ohm range to 5000 Ω.

As a safety feature, the AC voltage range becomes effective as soon as the instrument is connected to the circuit under test. Therefore, a warning is given that the circuit under test is not de-energised before the instrument is operated. Though calibrated for AC voltage, this range also monitors the automatic discharge feature so that after equipment having capacitance (i.e., a cable), has been tested, an indication can be given that the voltage has discharged to a level that is safe for removing the test leads.

It is portable and self-contained, designed to give rapid and accurate measurements. The instrument is protected for connection to power distribution systems up to 300 V Line-Ground and 500 V Line-Line for Installation Category III. This relates to transient overvoltage likely to be found in fixed installation wiring.

Please note that the 210600, 21017 and MJ359 have been discontinued.