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HomeNewsCauses of motor heating

Causes of motor heating

2020-07-31

During the course of use, the working temperature often rises or even unable to work. There are many reasons for the motor to heat up. Today, Zhengde Intelligent Control will communicate with you based on the actual situation.


Load problems cause the motor to overheat


● The dragging mechanical load is not working properly.

Although the equipment is matched, the mechanical load to be driven is not working properly, and the load is sometimes large and sometimes small during operation. For example, when the motor is equipped with a thresher, when the feeding amount is too large, the motor will heat up due to overload.


● Mechanical failure of the drag.

When the machine being dragged is faulty, inflexible or stuck, it will overload the motor and cause the motor winding to overheat.


● The motor is running under overload.

When the equipment is not matched and the load power of the motor is greater than the rated power of the motor, the motor will be overloaded for a long time (that is, the small horse-drawn cart) will cause the motor to overheat.

When repairing an overheated motor, you should first find out whether the load power is consistent with the motor power to prevent blind disassembly.


The power supply causes the motor to overheat


● The power supply voltage is asymmetrical.

When one phase of the power cord is disconnected, it will cause the three-phase motor to run in a single phase, causing the operating two-phase winding to pass through a large current and overheat, causing the motor to burn out. It is often said that the motor is damaged by phase loss.


● The power supply voltage is too high.

When the power supply voltage is too high, the back electromotive force, magnetic flux and magnetic flux density of the motor will increase accordingly. Since the iron loss is proportional to the square of the magnetic flux density, the iron loss increases, causing the iron core to overheat. The increase in magnetic flux also causes the component of the excitation current to increase sharply, resulting in increased copper loss in the stator winding and overheating of the winding. Therefore, when the power supply voltage exceeds the rated voltage of the motor, the motor will overheat.


● The power supply voltage is too low.

When the power supply voltage is too low, if the electromagnetic torque of the motor remains unchanged, the magnetic flux will decrease, and the rotor current will increase accordingly, and the load power component in the stator current will increase accordingly, which will increase the copper loss of the winding and cause the stator and rotor windings to overheat .


● The three-phase power supply is unbalanced.

When the three-phase power supply is unbalanced, the three-phase current of the motor will be unbalanced, and zero-sequence and negative-sequence currents that do not perform work flow in the motor windings, causing the windings to overheat.

When the motor is overheated, the elimination method is adopted, and the power source should be considered first.


Poor ventilation and heat dissipation make the motor overheat


● The ambient temperature is too high and the inlet air temperature is high.


● Excessive dust inside the motor affects heat dissipation.


● The fan is damaged or installed backwards, resulting in no wind or low air volume.


● There is no wind cover or no wind baffle in the motor end cover, resulting in no suitable air path for the motor.


● The air inlet is blocked by sundries, which makes the air inlet difficult and causes a small amount of air inlet.


The motor itself causes overheating


● When the motor winding has a short-circuit fault, the short-circuit current is much larger than the normal working current, which increases the copper loss of the winding and causes the winding to overheat or even burn.


● The motor connection is wrong.

When the delta connection motor is wrongly connected into a star shape, if the motor is still running with full load, the current flowing through the stator winding will exceed the rated current, and even cause the motor to stop by itself. If the motor is stopped for a long time and the power supply is not cut off, the winding will not only Severe overheating will burn the motor.

When a star-connected motor is wrongly connected to form a triangle, or a motor with several coil groups connected in series into a branch is connected to two branches in parallel, the winding and the iron core will overheat, and the winding will be burnt in severe cases.


● The motor winding is open circuit.

When one of the windings of the motor is broken, or one of the parallel branches is broken, it will cause the three-phase current to be unbalanced and the motor will overheat.


● Mechanical failure of the motor.

When the motor shaft is bent, poorly assembled, bearing failure, etc., the motor current will increase, copper loss and mechanical loss will increase, and the motor will overheat.


● Motor process wiring.

When a coil, a group of coils or a phase winding is connected reversely, it will cause a serious imbalance of the three-phase current and overheat the winding.

Shenzhen Maintex Intelligent Control Co., Ltd.
Business Type:Manufacturer
Product Range:DC Motor , AC Motor , Stepper Motor
Products/Service:Stepper Motor , Brushless motor , Dc motor , treadmill used motor , Brushed Dc Motor , Fuji motor
Certificate:ISO14001 , ISO/TS16949 , ISO9001 , RoHS
Company Address:Zhengde Science Park, No. 8, Pingdi Street, Longgang District, Shenzhen, Guangdong, China

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