The Megger® WM6 tester is a self-contained instrument designed to give rapid and accurate resistance measurements. The hand-operated generator is coupled with the latest electronic technology, thus allowing the WM6 to test insulation at 500 V d.c. up to 200 M-ohm.

A low-voltage, hand-cranked, a.c. brushless generator, which is easy to turn by hand, is the power source. It is connected to a stabilized electronic invertor to provide the test voltage. All resistance readings are given directly on a moving-coil meter with a rugged taut-band suspension movement, a white-on-black scale and an orange “dayglow” pointer. This gives goodlegibility in most lighting conditions.An electronic circuit is used to give a four-decade resistance scale for insulation measurement.

There is a slider switch for selection of either the insulation resistance or continuity functions, and the strong ABS plastic case has a recess to accommodate the folded away generator handle for compactness. Two 4-mm terminal sockets are fitted into the side of the case for connecting the test leads.