Motor Insulation Resistance Test Values

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Motor insulation resistance test values.

Curve b shows same values corrected to 20 c see page 22 giving a definite downward. For 11kv equipment mi. Dc voltage of 500 or 1000 v is applied between the windings and the ground of the motor. A general rule of thumb is 10 megohm or more.

3 shows a typical scale which reads increasing resistance values from left up to infinity or a resistance too high to be measured. The insulation system of an electrical motor is said to be in good condition if. During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched. Ground insulation test of a motor.

Curve a shows test values as measured. Since 80 of electrical maintenance and testing. Check full load amps flas with the appropriate meter when the motor is turned on or with a full preference. Minimum insulation resistance ir value is depend upon rated line voltage of equipment.

B kv is the rated machine terminal to terminal voltage. The measurement of insulation resistance is carried out by means of a megohmmeter high resistance range ohmmeter this is how the test works. Set the voltage level of the insulation resistance tester to 500v. 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.

Check the motor frame earth from phase to phase u to e v to e w to e. The international electrical testing association neta specification maintenance testing specifications for electrical power distribution equipment and. Ansi neta mts 2015 table 100 11 insulation resistance test values rotating machinery for one minute at 40 c. A rated line to line voltage for three phase ac machines line to ground voltage for single phase machines and rated direct voltage for dc machines or field windings.

Values based on ieee std 43 2013. Figure 4 typical record of insulation resistance of a mill motor. Set the voltage. Also acceptable values of insulation resistance depend upon the equipment you re testing.

Minimum ir in megohm kv 1 example 1. If during periodical testing insulation resistance of cable is found between 5 and 1 m. Determine rules for the actual minimum insulation resistance value of an electric motor because resistance varies according to method of construction condition of insulation material used rated voltage size and type. I want to know the value measurements of resistance for motor it is capacity is 1mw the applied voltage is 600v because i have a re winding motor and i want to comparing the results with slandered values.

For a 440v motor minimum ir between phase and ground 440 1000 1 1 44 megohm example 2.