The nameplate of the motor is gone. How do you calculate the power of the motor by measuring the resistance?
The motor nameplate is off. It is impossible to calculate the motor power by measuring the resistance. If it is some common standard motor, you can measure the center height, the installation hole distance, determine the frame size, the diameter of the shaft, and then check the manual. Maybe you can find the approximate power range. This also requires a certain amount of field experience. For example, those who have more motor repairs can find out more about the talents. If it is a motor with a partial door, rely on this method. It won't work.
1. To know the power of the motor, of course, you need to know the voltage and current of the motor. If it is a servo motor and a stepper motor, the voltage may not be very standard, so it is not easy to judge. You can find the parameters from the driver. Maybe it will be more ideal. Of course, ordinary AC asynchronous motors and DC motors, if there are drives such as inverters and DC converters, the parameters of the drive can be judged by the parameters of the drive, because the power of the drive is generally equal to the rated power of the motor, or high. One level.
2. For the three-phase asynchronous motor, the domestic type is also relatively easy, because the domestic three-phase power is three-phase 380 volt AC, so only need to know the current. Of course, the current needs to be measured on site. Generally, when the motor is designed, it will not run at full load, that is, the load current. Normally, it should be within 80% of the rated current. Through the field clamp meter, the line current of the motor can be measured. Introduced the approximate rated current.
3. It is also possible to energize the motor separately. Of course, it is also a common AC asynchronous motor. Then it runs at no load and measures the no-load current with a clamp meter. Under normal circumstances, the no-load current is about 30% of the rated current. Reverse the rated current of the motor.
4. For single-phase motors, the size of the motor can be estimated based on the starting capacitor and the running capacitor. The capacitor generally has a capacity, and this determines the power range of the motor. Generally, when the starting capacitor is selected, it is calculated according to the formula: capacity = 1950 × I / U × COSφ (μF), so that COSφ can take 0.75, and the voltage is of course 220V single phase, so that the current I can be calculated.
5, know the motor current, power factor can be considered according to 0.8, motor power = voltage * current * power factor, so you can roughly calculate the motor power, and then through the size of the motor, find a similar power motor size comparison, see See if it is consistent, so as to prove the rationality of the motor power.
6. Of course, if you are repairing the motor, you can completely disassemble to see the number of turns, the number of slots, the wire diameter, the length of the core, the number of windings, the wiring method of the outlet, and then compare the manual to judge, but the average person is doing Not enough.
