Motor Insulation Resistance Test Values

Since 80 of electrical maintenance and testing.

Motor insulation resistance test values.

The measurement of insulation resistance is carried out by means of a megohmmeter high resistance range ohmmeter this is how the test works. For 11kv equipment mi. Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv. B kv is the rated machine terminal to terminal voltage.

Minimum ir in megohm kv 1 example 1. Check the motor frame earth from phase to phase u to e v to e w to e. The minimum test value of motor insulation resistance is 1 meg ohm 1 mh. Values based on ieee std 43 2013.

The international electrical testing association neta specification maintenance testing specifications for electrical power distribution equipment and. Hands down without a doubt one of the most universally searched topics on ec m s website from a historical perspective is insulation resistance testing as a result some of our most popular evergreen articles like understanding insulation resistance testing continue to top the charts when it comes to most popular content. A general rule of thumb is 10 megohm or more. Also acceptable values of insulation resistance depend upon the equipment you re testing.

Minimum insulation resistance ir value is depend upon rated line voltage of equipment. During the measurement and immediately afterwards some of the terminals carry dangerous voltages and must not be touched. Ground insulation test of a motor. Ansi neta mts 2015 table 100 11 insulation resistance test values rotating machinery for one minute at 40 c.

Insulation resistance test insulation resistance failure of an electric motor is one of the first signs that the motor is about to fail. Figure 4 typical record of insulation resistance of a mill motor. The insulation system of an electrical motor is said to be in good condition if. If during periodical testing insulation resistance of cable is found between 5 and 1 m.

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. 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. Dc voltage of 500 or 1000 v is applied between the windings and the ground of the motor. 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.

Set the voltage. Curve b shows same values corrected to 20 c see page 22 giving a definite downward. 3 shows a typical scale which reads increasing resistance values from left up to infinity or a resistance too high to be measured. Set the voltage level of the insulation resistance tester to 500v.

Check full load amps flas with the appropriate meter when the motor is turned on or with a full preference.