The frequency of the national standard three-phase alternating current is 50HZ, which means that the voltage per second should be changed 50 times according to the sine law.
The frequency of the national standard three-phase alternating current is 50HZ, which means that the voltage per second should be changed 50 times according to the sine law.
The steering and phase sequence of a three-phase asynchronous motor are directly related. The steering of the vacuum pump is deterministic and cannot be reversed, so the phase sequence must be accurate and the reversal will damage the vacuum pump.
The motors used in vacuum pumps are all AC motors, mainly three-phase asynchronous motors and single-phase asynchronous motors. Motors below 4KW are generally star-connected (220V/380V), and those above 4KW are generally connected by triangle (380V/660V). But this is not necessarily absolute, the wiring must be carried out according to the motor nameplate identification.
When the motor is running, the motor must heat up due to the copper loss and iron loss caused by the coil and the iron core and the heat generated by the mechanical friction. When the heat cannot be dissipated in time, the temperature of the coil exceeds the high temperature that the coil insulation material can withstand. The insulating material will age, become brittle, and the back insulation will be broken down until the coil is burnt.
The main reasons for the vacuum pump motor burnout are as follows:
1. Operating under overload conditions for a long time
1 The wrong vacuum pump oil was used. When the vacuum pump lacked maintenance, the vacuum pump oil in the pump deteriorated.
2 When the exhaust pressure of the pump is too high, it will cause the motor to be overloaded. If there is no certain overload protection, it will damage the motor after a long time.
2. Operating at high ambient temperatures and poor ventilation or altitudes above 1000 meters
Due to poor heat dissipation, the temperature rise of the motor is too high, which may damage the coil of the motor and consume grease in the bearing, causing damage to the bearing.
3, the voltage is wrong
Some pumps may be imported. The rated voltage of the motor is different from the voltage in our country. Excessive voltage and too low voltage will damage the motor.
4, wiring error
1 should be connected to the star type, connected to the triangle type, will cause the coil voltage to increase by 1.7 times, the winding of the motor will be severely heated, the motor will burn out quickly, so the motor must not be allowed to change the original star connection at the same voltage. triangle.
2 should be connected to a triangle type. When connected to a star type, the voltage of the motor coil is reduced to 1/1.7, and the torque of the motor is reduced to 1/3 of the rated value. At full load operation, the speed will drop sharply and the current will increase. If the machine is not stopped, the motor will overheat and burn out.
3 Some side-flow vacuum pumps are connected to a star shape due to incorrect wiring. In the test machine, the load is very small, the pump can run normally, but after a certain period of operation, the pump filter is blocked. An increase in the load on the pump can result in damage to the motor.
5, did not use the correct electrical protection device and high-quality electrical control components
1Because sometimes when using a vacuum pump, simply wiring the pump directly to the vacuum pump without proper overload protection, phase loss protection, etc., causes the motor to burn out due to various accidents.
2 In some cases, it is necessary to frequently turn off the vacuum pump, and even open and close several times in one minute. Once the contact of the contactor is bad, phase loss will occur.
The measures to prevent the burnout of the vacuum pump motor are as follows:
1. All professional electrical work must be carried out by a professional electrician.
2. Check the rated voltage and frequency of the motor. Carefully check the nameplate for wiring. If it cannot be confirmed, first connect it to the star type, start it under no load, and gradually increase the load to check the current.
3. The ambient temperature of the vacuum pump is better than 40 degrees, and the ventilation is good.
4. According to the instruction manual of the vacuum pump, timely maintenance should be carried out correctly.
----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant
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