Quck answer
To test if a motor winding is grounded, follow these steps:
1. Disconnect the motor from the power source and make sure it is completely de-energized.
2. Use a multimeter set to the resistance or continuity mode.
3. Connect one probe of the multimeter to the motor winding terminal and the other probe to the motor’s metal frame or ground.
4. If the multimeter reads a low resistance or shows continuity, it means the winding is grounded.
5. If the multimeter shows high resistance or no continuity, the winding is not grounded.
Remember to always prioritize safety when working with electrical equipment and consult a professional if unsure.
A motor malfunctions when its windings come into contact with the ground, with each other, or when there is a break in the wire of the winding. The windings of the motor are covered with insulation to provide isolation. If this insulation wears away near the motor’s casing, the bare wire of the winding will connect to the ground. In order to ensure proper maintenance or before replacing the motor, technicians should conduct a series of tests, including checking for grounded windings.
Step 1
Disconnect the power supply to the motor. If the motor is plugged into a wall socket, unplug it. If the motor is connected to a circuit breaker, such as an air-conditioning compressor-motor, switch off the appropriate circuit breaker.
Step 2
Access the electrical connections and casing of the motor. Different types of motors require different methods of access. For example, remove the back panel of a refrigerator to reach the condensing fan motor, or detach a ceiling fan to access its motor.
Step 3
Label each motor wire using masking tape and a pencil. Write down the wire’s terminal identification on the tape. In most cases, the terminals have labels next to them.
Step 4
Disconnect all the motor wires. If the wires have slide-on terminal connectors, use needle-nose pliers to grip the connector and pull it off the terminal. If the motor uses screws to secure the terminal connectors, loosen the screw with the appropriate screwdriver, usually a Philips-head, and remove the connector.
Step 5
Set a multimeter or ohmmeter to the highest resistance setting. A multimeter has settings for voltage, amperage, and resistance. An ohmmeter measures resistance.
Step 6
Touch one of the meter’s probes to the motor’s casing. If the manufacturer has painted the casing, scrape off a small area with a screwdriver and place the probe on the exposed metal.
Step 7
Touch the second probe of the meter to one of the motor’s wire terminals. Read the meter. The meter should show an infinite reading. If it does not, then the motor’s windings are connected to the ground. Repeat this step for each wire terminal.
