How does the screw air compressor manufacturer solve the motor can not start

The motor is an important component driving the operation of the air compressor. Once a failure occurs, it will seriously affect the operation of the factory's production. Therefore, it is very important to understand the possible failures of the motor and the general solutions. The following screw air compressor manufacturers Introduce some reasons and preliminary solutions about the failure of the motor to start.

1. The motor does not turn and there is no sound. The reason may be a two-phase or three-phase open circuit in the power supply or winding. First check whether there is a power supply voltage. If there is no voltage in the three phases, the fault is in the circuit; if the three-phase voltage is balanced, the fault is in the motor itself. At this time, the resistance of the three-phase windings of the motor can be measured to find out the windings of the open phase.

2. The motor does not rotate, but there is a "humming" sound. Measure the motor terminal, if the three-phase voltage is balanced and the rated value, it can be judged as a serious overload.

The inspection procedure is to remove the load first. If the motor speed and sound are normal, it can be determined that the load is overloaded or the mechanical part of the load is faulty. If it still does not turn, you can turn the motor shaft with your hand. If it is tight or unable to turn, measure the three-phase current; if the three-phase current is balanced but larger than the rated value, it may be that the mechanical part of the motor is stuck or the motor Lack of oil, bearing rust or severe damage, end caps or oil caps are installed too obliquely, rotor and inner bore collide (also called sweeping bore). If you feel that it is difficult to turn the motor shaft to a certain angle by hand, or if you hear a periodic "chatter" sound, it can be judged as sweeping. The reasons may be:

(1) The gap between the inner and outer rings of the bearing is too large, the bearing needs to be replaced

(2) The bearing chamber (bearing hole) is too large, and the inner hole diameter is too large due to long-term wear. The emergency measure is to electroplate a layer of metal or add a sleeve, or you can wash some small spots on the inner wall of the bearing

(3) The shaft is bent and the end cap is worn

3. The motor rotates slowly and is accompanied by a "humming" sound, and the shaft vibrates. If the measured current of one phase is zero and the current of the other two phases greatly exceeds the rated current, it means that it is two-phase operation. The reason is that the circuit or power supply is open in one phase or the motor winding is open in one phase.

When one phase of the small motor is disconnected, it can be checked with a megohmmeter, a multimeter or a school lamp. When inspecting a motor with star or delta connection, the joints of the three-phase winding must be disassembled, and each phase shall be measured for open circuit. The windings of medium-capacity motors mostly use multiple wires and are connected in parallel around multiple branches. It is more complicated to check if several wires are broken or one parallel branch is disconnected. The three-phase current balance method and the resistance method are often used. Generally, when the difference of the three-phase current (or resistance) value is more than 5%, the phase with the small current (or the large resistance) is the open circuit phase. Practice has proved that motor open circuit faults mostly occur at the ends of the windings, joints or lead wires.