What is the cause of excessive current in the micromotor? What is the cause of excessive motor curre

From the point of view of the starting principle and rotation principle of the micromotor, when the micromotor stops, it is equivalent to a transformer from the electromagnetic point of view, the stator winding can be compared to the primary coil of the transformer, and the rotor winding of the closed circuit is the forced convection coil of the transformer short circuit.

The stator winding and the rotor winding are not electrically connected, only the magnetic connection, the magnetic flux through the stator, the air gap and the rotor core will form a closed circuit, at the moment of closing, the rotor will not rotate because of the relationship of inertia, at this time, the rotating magnetic field will be at a relatively large cutting speed, cutting the rotor winding, the induction of the rotor winding will reach a high potential, so a relatively large current will flow in the rotor conductor, and the current will affect the magnetic energy of the stator magnetic field. Simply put, it cancels out the magnetic energy.

In order to adapt to the original magnetic flux, the stator will increase the current, the current of the rotor is very large, and the current of the stator will also increase, which will be several times higher than the rated current. This is the main reason for the starting current of the micromotor.

It may be that the load is too large, in this case, we should pay attention not to exceed the rated power of the micromotor, and the resistance of the load can be reduced to solve this problem, the resistance is paralleled, which may not take the load or the load is damaged, and the other method is to give the micromotor string a constant voltage, but there is also the possibility of damaging the device.

This may be caused by the misalignment of the motor or the commutator spark of the motor.

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.

The reasons for excessive motor current are as follows:

1. The power supply voltage is too high, when the power supply voltage is too high, the motor core will produce magnetic saturation, resulting in excessive no-load current.

2. The motor is improperly assembled or the gap is too large after repair.

3. For some old motors, due to the corrosion or aging of the silicon messy silver steel sheet, the magnetic field strength is weakened or the insulation between the pieces is damaged, and the no-load current is too large, for small motors, the no-load current can continue to be used as long as it does not exceed 50% of the rated current.

The reasons for the low current of the motor are:

1. The number of turns of the stator winding is more than the normal value;

2. The air gap between the stator and rotor is small;

3. The quality of silicon steel sheet is too poor;

4. The winding wiring is wrong, such as the three-phase triangle connection is actually a three-phase Y connection;

5. The number of winding parallel circuits is less than the design value;

6. The motor with a rated frequency of 50Hz is connected to 60Hz alternating current;

7. The power supply voltage is lower than the rated value;

8. The resistivity of the rotor cast aluminum is greater than the design requirements, that is, the iron content of the aluminum composition is higher;

9. The wrong rotor is used, and the resistance of the rotor used is greater than that of the applied rotor.

Motor refers to an electromagnetic device that converts or transmits electrical energy according to the law of electromagnetic induction.

The motor in the circuit is represented by the letter M (the old standard is D), the main role is to generate driving torque, as a power source for electrical appliances or various machinery, the generator in the circuit is represented by the word brother grinding mother G, its main role is to use mechanical energy to convert into electrical energy.

In the household dust removal electrical equipment, such as electric fans, refrigerators, washing machines, range hoods, vacuum cleaners, etc., the working power of the single-phase AC motor is adopted. The structure of this motor is relatively simple, so some common faults can be repaired in amateur conditions.

1. The number of turns of the stator winding is more than the normal value;

2. The air gap between the stator and rotor is small;

3. The quality of silicon steel sheet is too slippery and poor.

4. The winding wiring is wrong, such as a three-phase triangle.

The ambush bureau is actually a three-phase Y-connection.

5. The number of winding parallel circuits is less than the design value;

6. The motor with a rated frequency of 50Hz is connected to 60Hz alternating current;

7. The power supply voltage is lower than the rated value;

8. The resistivity of the rotor cast aluminum.

Greater than the design requirements, i.e. the composition of aluminum has a higher iron content.

9. The wrong rotor is used, and the resistance of the rotor used is greater than that of the applied rotor.

Because the stalled rotor torque is proportional to the stalled rotor current, if the stalled rotor current of the motor is small, it may cause the stalled rotor torque to fail to meet the standard requirements when the rated voltage is used, resulting in the motor being weak and unable to start.

The motor current is small, because the load does not reach the rated value, that is, in the no-load state, the current is ultra-low, the car shelter with the load increases, the current will increase, Qi Ru has been large to the rated current, then the load is increased, the motor is overloaded, there is a possibility of burning, I really help you close the state expectation,

Reasons for the low current of the motor:

1. The number of turns of the stator winding is more than the normal value;

2. The air gap between the stator and rotor is small;

3. The quality of silicon steel sheet is too poor;

4. The winding wiring is wrong, such as the three-phase triangle connection is actually a three-phase Y connection 5, and the number of winding parallel circuits is less than the design value.

6. The motor with a rated frequency of 50Hz is connected to 60Hz AC 7, and the power supply voltage is lower than the rated value.

8. The resistivity of the rotor cast aluminum is greater than the design requirements, that is, the composition of the aluminum has a higher iron content 9. The wrong rotor is used, and the rotor resistance used is greater than that of the applied rotor due to the proportional relationship between the locked-rotor torque and the locked-rotor current, if the locked-rotor current of the motor is small, it may cause the stalled torque to fail to meet the standard requirements when the rated voltage is used, resulting in the motor is not energetic and cannot be started.

The temperature is large, but the current is small, this is impossible, can you elaborate on it.

1. The load becomes smaller.

2. The ammeter is broken.

3. CT is bad.