How to use a megger on motor

Very good explanation of HV insulation testing and its value. Insulation resistance failure of an electric motor is one of the first signs that the motor is about to fail. This test may take place on installed or on-the-reel cable, tools, appliances, transformers, power distribution subsystems, capacitors, motors and any type of electrical equipment or wiring. The test may be non-destructive for in- service equipment.

Industries of today use three-phase motors widely in high-power applications.

Using Megohm meter insulation resistance is measured.

Periodic testing is, therefore, your best approach to preventive maintenance of electrical equipment, using record cards as shown in Fig.

The Complete Guide to Electrical Insulation. If the motor is not put into operation immediately upon arrival, it is important to protect it against external factors like moisture, high temperature and impurities in order to avoid damage to the insulation. Check the appearance of the motor. Note the motor data from the motor NAME PLATE. Earth Continuity: Use your ohmmeter to verify the resistance . I suspect either the motor locked up and burnt the insulation on the windings or the winding suffered mechanical damage from the broken internal . In this we check induction motor by megohmeter.

Power Supply Test For single phase motors , the expected voltage is about 230V or 208V depending whether you are using the UK or America voltage system. Working through the system Motor to disconnect,overloads, contactor and. NC contact, this made it look initially that the fault was one of the motors or the CCH itself. Suspected the fault was in the milk tank control circuit but it turned o. Construction of Three Phase Motors. Megger Testing: Tracing Electrical short.

Connecting Three Phases Motors. Meggers can be used for other electrical devices other than electric motors. This one covers testing the resistance to ground using both the meggohmmeter and the insulation tester.

Bear in mind that insulation resistance values will vary w. I said the volts should read zero, . How to measure insulation resistance of motor by using Megger. The motor and phase rotation tester permits the electrical contractor or industrial maintenance electrician to permanently . The megger will help to detect areas of deteriorating insulation where the windings may soon short. But this standard is for motors that are not hermetically sealed with oil and refrigerant.

A motor submersed in liquid may need to use lower values as recommended by the manufacturer.