How do you test a dc motor with a mega meter?

Answer 1

A megameter, or a Megger as it is commonly called, is used

to measure the insulation resistance of cables and other

electrical equipment. The measured value is in mega ohms.

Hence the term Megger.

Most meggers generate 500 Volts DC supply, but their

current capacity remains low.

When the two terminals of a megameter is connected to

across the equipment to be tested, the high voltage gets

leaked into the equipment. The resistance is inversely

proportional to the current flowing through the equipment

under test.

Originally, most meggers were analog in nature, and were

generating high voltage using a dynamo, when the lever is

rotated at high speed.

Today most meggers available are digital, and can

generate 500 volts as well as 1000V. Some meggers have

winding resistance testing facility as well, and hence can

be used as a single tool to test the resistance of a motor

in ohms as well as in Megaohms.

Meggers used for checking high resistance like that of

mains transformrs, generate much higher voltages and are

generally analog type.