Ac Motor Insulation Resistance Test

Smaller systems will remain steady because the capacitive and absorption currents drop to zero faster than on larger systems.

Ac motor insulation resistance test.

The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. If the rated voltage is 690 v 0 69 kv the minimum insulation resistance is. The minimum insulation resistance of new cleaned or repaired windings with respect to ground is 10 megohm or more. For low voltage installations i e.

The megger insulation tester is essentially a high range resistance meter ohmmeter with a built in direct current generator. The minimum insulation resistance r is calculated by multiplying the rated voltage u n with the constant factor 0 5 megohm kv. Set the voltage setting of the insulation resistance tester to 500v. Ac insulation testing better simulates the day to day stresses undergone by power systems including frequencies like 50 60 hz without causing the insulation breakdown common in dc testing.

0 69 kv x 0 5 megohm kv 0 35 megohm. Insulation resistance testing to check for degradation of motor winding insulation check for the presence of contaminants that affect the results of ir testing. Additionally ac testing won t affect xlpe cables when used for over potential testing to an agreed acceptable insulation resistance value. Larger insulation systems will show a steady decrease.

How to measure insulation resistance of a motor the measurement of insulation resistance is carried out by means of a mega ohmmeter a high resistance range ohmmeter. Using insulation testing with an instrument such as the fluke 1555 10 kv insulation tester combined with fluke connect technology such leaks can be detected as insulation resistance slowly tapers over time a sign of normal and expected deterioration. The first ir test to trend requires the compressor to have been off the second test is conducted after the compressor has operated for five or ten minutes. The measured resistance indicates the condition of the insulation between two conductive parts.

An insulation resistance tester supplies non destructive dc voltages to the windings and insulation points of a motor to measure the current leakage rate. 230v to measure insulation resistance in ohm s. The insulation resistance test is an electrical test which uses a certain type and level of voltage 500v d c. The insulation keeps the current flowing along the wire exactly as intended.

When performing insulation resistance testing you must maintain consistency. After 1 min you should read and record the resistance value. For a three phase motor insulation resistance is usually measured between each motor winding or phase and between each motor phase and motor frame earth using an insulation tester or megger. For good insulation the resistance usually reads in the megohm range.