How does the tester do this i.e. creating high voltage & low amps?
Answer The rotating handle type has an actual generator inside which builds up a high voltage and applies it to a capacitor; the voltage on the capacitor is then used to stress the line you are testing. Current is measured under the stressed condition which gives the resistance or breakdown condition. The portable battery operated units use a voltage multiplier to bring the voltage up to the testing level. Some may use a dc to dc inverter circuitry as well. But, the general idea of a megger tester is to stress the line under test with a high voltage and to measure the resistance or breakdown voltage under the stress of the applied high voltage. Let me know if you need more information.
