2 Tips to Solve the Overload in The Vacuum Oil Filter Motor

2021-08-25

The electric motor in the vacuum filter is electricity and magnetism. Electromagnetism is to use a straight metal wire to pass current, then a circular magnetic field will be generated in the space around the wire. The greater the current flowing in the wire, the stronger the magnetic field generated. The magnetic field is circular and surrounds the wire, while with some incidents there would be an overload, in the following article I will show you why it happens and what to deal with it.

 

5 Causes of Motor Overload And Heat Generation

A vacuum oil filter motor is a common cause of severe heating.

 

1. The air gap between the stator and rotor of the motor is very small, which may cause a collision between the stator and rotor. 

 

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In medium and small motors, the air gap is generally 0.2mm~1.5mm. When the air gap is large, the excitation current is required to be large, thereby affecting the power factor of the motor; if the air gap is too small, the rotor may friction or collision. Generally, due to the serious over-tolerance of the bearing and the wear and deformation of the inner hole of the end cover, the different axis of the base, the end cover and the rotor will cause the bore, which can easily cause the motor to heat up or even burn. If the bearing is found to be worn, it should be replaced in time, and the end cover should be replaced or brush-plated. The simpler treatment method is to set the end cover.

 

2. Abnormal vibration or noise of the motor can easily cause the motor to heat up

This situation belongs to the vibration caused by the motor itself, most of which are due to poor rotor dynamic balance, poor bearings, bent shafts, end caps, bases, and rotors with different shaft centers, loose fasteners, or motor installation foundations that are uneven or improperly installed. The cause may also be transmitted from the mechanical end, which should be eliminated according to specific circumstances.

 

3. The abnormal bearing operation will inevitably cause the motor to heat up

Whether the bearing works normally can be judged by hearing and temperature experience.

 

You can check the bearing end with your hands or thermometer to determine whether the temperature is within the normal range; you can also use a listening rod (copper rod) to contact the bearing box. If you hear an impact sound, it means that one or several balls may be crushed. The sizzling sound means that the lubricating oil of the bearing is insufficient, and the motor should be changed once every 3,000 to 5,000 hours of operation.

 

4. The power supply voltage is too high, the excitation current increases, and the motor will overheat

Excessive high voltage will endanger the motor insulation and cause it to be broken down. When the power supply voltage is too low, the electromagnetic torque will decrease. If the load torque is not reduced and the rotor revolutions are too low, the increase in the slip will cause the motor to overload and generate heat. Long-term overload will affect the life of the motor. When the three-phase voltage is asymmetric, that is, when the voltage of one phase is too high or too low, it will cause a certain phase current to be too large, the motor will heat up, and the torque will be reduced at the same time, it will make a "buzzing" sound, which will damage the windings for a long time.

 

In short, no matter the voltage is too high, too low, or voltage asymmetry, the current will increase, and the motor will heat up and damage the motor. Therefore, according to the national standard, the change of the motor power supply voltage should not exceed ±5% of the rated value, and the motor output power can maintain the rated value. The motor power supply voltage is not allowed to exceed ±10% of the rated value, and the difference between the three-phase power supply voltages should not exceed ±5% of the rated value.

 

5. Winding short-circuit, inter-turn short-circuit, phase-to-phase short-circuit, and winding open circuit

After the insulation between two adjacent wires in the winding is damaged, the two conductors collide, which is called a winding short circuit. Winding short circuits that occur in the same winding are called inter-turn short circuits. A winding short circuit that occurs between two-phase windings is called an interphase short circuit. Either way, it will increase the current of one or two phases, causing local heating, and aging the insulation, and damaging the motor. Winding open circuit refers to the fault caused by the broken or blown-out of the stator or rotor winding of the motor. Whether the winding is short-circuited or open, it may cause the motor to heat up or even burn. Therefore, it must be shut down immediately after this situation occurs.

 

2 Methods of Troubleshooting the Motor Overload of the Vacuum Oil Filter

1. You must be familiar with the characteristics and causes of common motor faults, grasp the key factors, and conduct regular inspections and maintenance.

 

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2. The detection circuit eliminates the abnormality caused by the wrong connection of the circuit and eliminates the fault as soon as possible so that the motor is in a normal operating state. So as to ensure the normal production of Vacuum Oil Filter.