What is the cause of motor current overload

Under normal operating conditions, the motor can always maintain the balance between the load torque and the output torque of the motor, and keep the speed change very small, but when the load torque is too large and exceeds the rated torque, the motor still has to maintain the torque balance, only reduce the speed, continue to increase the torque, (if the torque exceeds the maximum load torque motor will stall) The continued increase of torque will inevitably lead to the increase of stator current, which will lead to an increase in the heating of the stator winding, If it continues to be overloaded, it will create a no-load current, you can check the electrician's manual. Generally around half. Is the stirred liquid viscous?

Just like the dough mixer, the current gradually increases to the point that the motor burns out.

1. It may be an abnormal phenomenon caused by the aging of the motor after it has been used for too long. For some old motors, due to the corrosion or aging of silicon steel sheets, the magnetic field strength is weakened or the inter-piece insulation is damaged, which will cause too much no-load current.

2. It may be that the power supply voltage of the motor is too high. When the power supply voltage is too high, the motor iron core will produce magnetic DU saturation, resulting in excessive no-load current. In this case, the voltage of the power supply can be adjusted.

3. It may be an abnormal phenomenon caused by improper assembly or too large void of the motor after repair.

4. It may be that the number of turns of the stator winding is not enough or the Y-type connection is mistakenly connected into a triangle wiring.

5. It may be that the load of the motor is too large and exceeds the power allowable range of the motor.

It is normal for the current of the motor to be larger, and for small motors, the no-load current can continue to be used as long as it does not exceed 50% of the rated current. If there is a problem with the motor, first check the motor to eliminate the cause of the fault, and repair the cause of the fault accordingly.

Dear, hello, I am glad to answer for you, how to eliminate the motor overload fault Answer: There is a thermal relay (overload protection) in the main circuit of the motor, when the motor is overloaded, the thermal relay acts, the normally closed contact cuts off the control circuit, and the normally open contact closes and turns on the indicator. After the overload is removed, the contacts of the thermal relay have two ways to reset the circuit to get the circuit back in operation

1. Manual reset - you need to press the reset button; 2. Automatic reset - overload removal, wait for a while, it will automatically return to normal after cooling. If you are in the manual reset position, after finding the thermal relay, press the red handle on it, and you can hear a "pop". Motor overload mainly has the following symptoms:

1. The heat generation of the motor increases; 2. The speed of the motor decreases, and may even drop to zero; 3. The motor has a low sound and general vibration; 4. If the load changes drastically, the speed of the motor will fluctuate high and low; Causes of motor overload: 1. Electrical reasons: such as phase loss, voltage exceeding the allowable value, etc.; 2. Mechanical reasons:

Such as excessive torque, motor damage (bearing vibration), etc.; There is a thermal relay (overload protection) in the main circuit of the motor, when the motor is overloaded, the thermal relay acts, the normally closed contact cuts off the control circuit, and the normally open contact closes and turns on the indicator. After the overload is eliminated, there are two reset ways for the contacts of the thermal relay to make the circuit start working again: 1. Manual reset - you need to press the reset button; 2. Automatic reset - overload removal, wait for a while, it will automatically return to normal after cooling.

If you are in the manual reset position, after finding the thermal relay, press the red handle on it, and you can hear a "pop". The main symptoms of motor overload are as follows: 1. The heat generation of the motor increases; 2. The speed of the motor decreases, and may even drop to zero; 3. The motor has a low sound and general vibration; 4. If the load changes drastically, the speed of the motor will fluctuate high and low; Causes of motor overload:

1. Electrical reasons: such as phase loss, voltage exceeding the allowable value, etc.; 2. Mechanical reasons: such as excessive torque, motor damage (bearing vibration), etc.; Generally, thermal relays have the function of automatic reset; If there is no automatic reset after a certain period of time, you can manually press the reset button of the hot relay.

1. Electrical reasons:

The motor voltage is too high or too low;

The motor has been seriously damp or corrosive gas erosion for a long time, which reduces the insulation resistance;

The winding connection method does not meet the requirements The winding that was originally Y-connected was mistakenly connected during maintenance.

2. Mechanical reasons: such as excessive torque, motor damage (bearing vibration), etc.;

overloaded; The lack of oil in the motor bearing, dry grinding or non-concentricity of the rotor machinery makes the motor current exceed the rated value;

Failure of the mechanical transmission part, etc.

3. Improper selection, long starting time, etc., the brake motor should have been used, and only the ordinary three-phase asynchronous motor was used in the place where the speed regulating motor was used.

There is a thermal relay (overload protection) in the main circuit of the motor, when the motor is overloaded, the thermal relay acts, the normally closed contact cuts off the control circuit, the normally open contact closes and turns on the indicator, after the overload is eliminated, the contact of the thermal relay has two reset ways to make the circuit start working again: manual reset - you need to press the reset button; Auto Reset – Overload removal, wait a while, it will automatically return to normal after it cools down.

Summary. According to the standard is the current setting value is the motor rated current times, the highest times, the overload protection is set at 120, the current motor design has been further scientific, Y2 series and its derivatives of the motor overload protection are set to 100. The current of the empty opening should be guaranteed to be at the rated current of 150 motor.

What is the current value when the motor is overloaded?

According to the standard is the current setting value is the motor rated current times, the highest times, the overload protection is set at 120, the current motor design has been further scientific, Y2 series and its derivatives of the motor overload protection are set to 100. The current of the empty opening should be guaranteed to be at the rated current of 150 motor.

Two hundred and fifty kilowatt electric motors. The maximum current for overload is 550 amps. We are referring to a 250 kilowatt electric motor, which is rated at 380 volts.

If a 250 kilowatt motor uses a 10 kilovolt power supply, its maximum current is about 50 amps. That is to say, the overload capacity of a motor current is to see that its output power does not exceed 10%, and if it is greater than 10%, it is not.

The full load current of the 250kw motor is 475A