Commonly used are single-phase motors and three-phase asynchronous motors
single phase motor

A single-phase motor generally refers to a low-power single-phase asynchronous motor powered by a single-phase AC power source (AC220V). This type of motor usually has two-phase windings on the stator and a common squirrel cage rotor. The distribution of two-phase windings on the stator and the different power supply conditions can produce different starting and operating characteristics.

Maintenance of single-phase motor faults

Step one, check the motor power supply to see if it is working properly

Step 2, check the circuit to see if it is connected and fixed, and if there are any open circuits or visible short circuits

If the motor does not start, but the motor rotor or fan blades are turned down and normal, measure the capacitance

Methods for detecting capacitors:

Check the capacitance range of the multimeter to see if the capacitance size is similar to the size on the capacitor nameplate, with some slight errors (if the multimeter has measurement errors, it is a normal phenomenon, but not much difference). If not, replace the capacitor with the same specification

For fixed capacitors above 0.01 μ F. The R × 1k gear of a multimeter can be used to directly test whether the capacitor has a charging process and whether there is an internal short circuit or leakage. The capacitance of the capacitor can be estimated based on the amplitude of the pointer swinging to the right. During the test operation, first touch the two pins of the capacitance with two probes at random, then replace the probe and touch again. If the capacitance is good, the pointer of the multimeter will swing to the right, and then quickly return to infinity to the left. The larger the capacitance, the greater the swing amplitude of the pointer. If the multimeter pointer does not swing to the right after repeatedly swapping the probes and touching the two pins of the capacitor, it indicates that the capacitance of the capacitor has fallen below 0.01 μ F or has disappeared. During measurement, if the pointer swings to the right and cannot return to the infinite position to the left, it indicates that the capacitor is leaking or has already been broken down. But if the capacitor loses capacity, it will also cause the motor to not start, so we still need to use the method of 1 to re measure

Motor quality inspection, tripping, slow running speed and other phenomena

Measure the resistance values between three wires using a multimeter. The highest resistance value is equal to the sum of the resistance values between the other two wires. The slightly higher resistance value represents the starting winding, while the lower resistance value represents the running winding. There is a common wire between the two, which is connected to one end of the power supply. If it is not correct, the motor coil will be short circuited or burned out

The maximum resistance gear of the multimeter is set, with one end of the probe connected to the motor housing and the other end connected to the motor output (measured separately with three wires), to see if there is a change in resistance. If there is, the motor is short circuited, and it is easier to determine with a shaking meter

There is also a buzzing sound and vibration sensation in some parts, which is due to excessive load

Of course, there are also mechanical problems such as motor rotors and bearings that cause loud noise. This is simply done by adding oil and increasing lubrication

Selection of capacitor capacity

Generally, it is not necessary to calculate because the starting capacitor only plays a phase shifting role. As long as it is matched with the starting coil, the electromotive force of the coil can be shifted to a 180 ° electric angle difference to generate a rotating magnetic field. After the motor starts, the starting coil and this capacitor are cut off. Therefore, this capacitor has a wide range of applications. Generally, 550W-2200W motors use 450V200 μ f and can start normally