A Common Method For Judging Whether A Three-phase Asynchronous Motor Is Burnt Out!


Watch: Look at whether the oil seal of the front bearin […]

Watch: Look at whether the oil seal of the front bearing end cap of the motor is black. Under normal circumstances, because the bearing is loose, the friction of the bearing oil seal rises too high and turns black. After the bearing is loosened, the broom is caused to short-circuit the coil or trip through the casing.

A common method for judging whether a three-phase asynchronous motor is burnt out


Smell: The coil will burn out due to overload or broom. Opening the junction box will smell the burnt smell after the coil is burnt.

Q: If the motor is overheated, ask the user of the motor whether the mechanical equipment is overloaded or if the transmission components are to be updated. For example, the cutter has a service life. Too old and not updated will cause the motor to overload and cause overheating.

Judge: "Cut" is the key. It is easy to judge the motor burnout. It is difficult to find out the cause of the motor burnout and eliminate the fault. Otherwise, the new motor will burn out.

Personal summary of the reasons for burning the motor: lack of phase, overload, coil aging, bearing loose broom, lock and block.

Whether the three-phase asynchronous motor burns out two commonly used judgment methods, the most commonly used:

First, insulation shake meter measurement

1. Insulation shaker measurement, select the appropriate insulation shaker 500 megaohms or 1000 megaohms, measure the insulation resistance between phase A, phase B, phase C and grounded casing of the three-phase winding, and shake the insulation shaker evenly. The insulation resistance of each phase measured by the insulation shaker is not less than 0.5 megohms.

A common method for judging whether a three-phase asynchronous motor is burnt out

2. Use the insulation shaker to measure phase A, phase B, and any two phases of phase C. When shaking evenly, the resistance between any two phases under normal conditions is around 0, and the resistance values of any two phases are almost the same.

Second, the multimeter is probably measured

1. First measure the three windings of the three-phase asynchronous motor to see if there is resistance, and the resistance value is the same!

Generally, the resistance of the three windings is about the same as the resistance. The closer the better, the magnitude of the resistance of the winding is related to the motor power. Generally, the larger the power, the smaller the resistance. The multimeter buzzer will sometimes ring.


2, the multimeter resistance high-end position, and then measure whether there is resistance between the winding and the motor casing, theoretically: the resistance between the winding and the motor casing is close to infinity, it is considered good insulation! At least the insulation resistance is above 0.5 megohms!

Third, the comprehensive use of multimeter and insulation shake meter measurement, multimeter to measure the phase resistance value and compare, insulation shake meter to measure the resistance value of any phase of the ground, and the value of the insulation resistance between phases!

Of course, there are many other methods for measuring whether the motor is burnt out. The above method is for the measurement of the three-phase asynchronous motor, and hopes to learn together!