Z 5 date of test r eading in megohms the graph below shows an example of the insulation resistance readings on an electric motor.
Motor insulation resistance test report format.
Curve a shows test values as measured.
Templates test reports forms tags.
Figure 3 typical scale on the megger insulation tester.
The test measures the insu lation resistance between the phases and or between phase and ground.
Power distribution equipment testing circuit tracing electrical survey panel schedules digital and affixed color coded labels affixed to.
The international electrical testing association neta specification maintenance testing specifications for electrical power distribution equipment and.
The insulation resistance is the resistance in ohms of wires cables and electrical equipment.
Insulation resistance quality of an electrical system degrades with time environment condition i e.
It is important to guard against electric shocks and avoid equipment damage from accidental discharges.
The method of measuring the insulation resistance is to test and assess the state of the isolation head and body.
Figure 4 typical record of insulation resistance of a mill motor.
During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched.
Reverse side of card at right is used to record the test data.
Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv.
Ground insulation test of a motor.
Insulation resistance testing is a non destructive test procedure.
Curve b shows same values corrected to 20 c see page 22 giving a definite downward trend toward an unsafe condition.
The measurement of insulation resistance is carried out by means of a megohmmeter high resistance range ohmmeter this is how the test works.
Dc voltage of 500 or 1000 v is applied between the windings and the ground of the motor.
Skip to content 516 536 2600 215 n main street freeport ny 11520.
Insulation resistance testing purpose.
The megger test is a method of testing making use of an insulation tester resistance meter that will help to verify the condition of electrical insulation.
At a the insulation resistance decreases due to aging and dust accumulation.
Also acceptable values of insulation resistance depend upon the equipment you re testing.
Regular checks of motor insulation resistance the key to prolonging the life of any electrical device is periodic checks maintenance the insulation resistance of stored and active motors should be checked regularly.
Temperature humidity moisture and dust particles.
