How can a multimeter be used to check whether a motor is burned out?

Measure the wiring resistance; if the resistance of all three wires is close to zero, or when using the highest resistance setting to measure between the terminals and the motor housing, and no resistance is detected, then the component is damaged.

Using a multimeter to check whether the motor is burned out involves primarily testing the resistance and insulation condition of the motor coils. Here are some basic steps: 1. **Turn off the power**: Before conducting the test, make sure the motor is disconnected from all power sources to avoid damaging the multimeter or causing danger. 2. **Check the appearance**: Before using a multimeter, it is possible to first inspect the appearance of the motor to see if there are any signs of burning, unusual odors, or other obvious damage. 3. **Adjust the multimeter**: Set the multimeter to the resistance setting (usually indicated by the Greek letter Ω); for testing small motors, it is advisable to choose a lower resistance range. 4. **Measure coil resistance**: Locate the motor’s terminal blocks or wires, and use the two probes of a multimeter to touch the terminals. If the motor is a three-phase motor, it is necessary to measure the winding resistance of each of the U, V, and W phases separately and keep records of them. For single-phase motors, measure across the two ends of the coil. If the motor is in good condition, it usually has a certain resistance value ； If it shows as infinity (OL or no display), the coil may be broken ； If it shows 0 or close to 0, the coil may be short-circuited. 5. **Check insulation**: Use the insulation resistance setting on a multimeter (if available) or a dedicated insulation resistance tester to measure the insulation resistance between the motor windings and the motor casing. One probe of the multimeter is connected to the motor casing (the metal part), while the other probe is connected to a terminal. Under normal conditions, this insulation resistance value should be quite high; if the reading is low, it indicates damaged insulation and a risk of short circuits. 6. **Professional advice**: If you are unsure about how to proceed correctly or interpret the data, you should seek help from professionals. In the absence of a dedicated insulation resistance tester, using the insulation resistance function of a multimeter to measure it may not be accurate, as the test voltage generated by the multimeter is likely much lower than the 500V or 1000V provided by an insulation resistance tester; this level of voltage may not be sufficient to detect even minor defects in the insulation. To assess the motor’s condition more accurately, a megohmmeter should be used to complement the measurements taken with a multimeter. .

There’s no need to use a megohmmeter; since it has already been damaged, an external meter will suffice. A megohmmeter is used for measuring insulation.

When there’s a problem with the motor, it’s usually because the winding coils inside have burned out. All that’s needed is to use a multimeter to check whether the resistance of the three windings is infinite, which will allow one to determine the issue