What is the reason for the lack of phase in the three phase motor? How to tell if the motor is out o

First, the performance of the motor when it is out of phase.

When combined, the high-power motor cannot operate and has a lot of mechanical noise, and the motor will burn out after three to five minutes. The low-power motor can run, but it is weak to run, and the windings will burn out after heating in one phase.

Second, the reason for the lack of phase of the motor.

1. The connector of the power conductor is loose or disconnected, and the contact of the gate knife or starting equipment is ablated, loosened and poorly contacted, resulting in a phase break.

2. The joint of the internal coil of the motor is desoldered or other reasons, resulting in the winding breaking, and the melt of the protection motor is grounded or short-circuited somewhere in the fusing motor for some reason during operation, and the local overheating phenomenon occurs, and the wire is burned off.

3. The fuse on the high-voltage side or low-voltage side of the distribution transformer is blown in one phase, in this case, all the motors powered by the transformer will run out of phase.

4. After the motor has been running for a considerable period of time, the insulation of the stator winding may be aging (the ambient temperature of the motor is too high for a long time. When the power supply voltage is high or the load is too large), it will cause a short circuit between phases or turns in the stator winding of the motor, and the stator winding of the motor will also be disconnected in one or more phases.

5. The contactors and relays in the control circuit are used for a long time, and there may be a certain degree of oxidation in the contacts. Cause poor contact, or long-term wear of the component action mechanism. These electrical components are malfunctioned when they are hit by the starting current of the motor, or by the vibration of the electromechanical equipment or the movement mechanism is stuck and malfunctioning, etc., and the stator winding is out of phase.

Reasons for the lack of phase in three-phase motors:

1. The power supply is out of phase.

The power supply is out of phase, that is, the power supply input to the motor is out of phase, and the cause of such failures is generally a fuse.

or automatic circuit breaker out of phase, AC contactor.

Phase-missing, thermal relays.

Lack of phase, lack of phase of the terminal block, or a line break. Judging this kind of fault is very simple, only need to use the voltage gear to measure at the input end of the motor when the circuit is turned on, if the three-phase any measurement results are seriously insufficient voltage, you can determine that it is this kind of fault.

2. The motor is out of phase.

The lack of phase of the motor is due to the overheating of the motor, or the bearing damage, loose joints, mechanical trauma, terminal breakage, etc.

If the three-phase balance is not a phase loss, if there is a phase or two phase breaks, it can be judged that the motor is out of phase.

Methods for judging the lack of phase of the motor:

1. Use a multimeter to measure the three-phase asynchronous motor.

The short circuit can be measured with a resistance gear to measure the resistance value of each phase winding, generally with the minimum gear, if the short circuit is basically zero, if there is 2 ohms.

The above is basically good. If there is a lack of phase, you can directly measure the resistance, and if there is resistance, it is good, and if there is no resistance, it means that there is a lack of phase. The value of the winding resistance to the ground is generally used by a shake meter.

Measured, the multimeter measurement is not accurate, more than 3 megaohms is good, less than 3 megaohms indicates that the insulation is not enough.

2. The noise of the three-phase motor when the phase is missing increases with the increase of the load, and the speed also decreases with the load size, the workmanship is weak, and the motor is generally not suitable for starting when the phase is missing.

Consequences of the lack of phase in a brushless motor:

One of the three-phase circuits of a brushless motor or brushless controller cannot work. Phase loss is divided into main phase absence and Hall phase loss. It is manifested as the motor shaking and cannot work, or the rotation is weak and noisy. It is easy for the controller to burn out when it works in a phase-out state.

One of the three-phase circuits of a brushless motor or brushless controller cannot work. Phase loss is divided into main phase absence and Hall phase loss. It is manifested as the motor shaking and cannot work, or the rotation is weak and noisy. It is easy for the controller to burn out when it works in a phase-out state.

If the three-phase motor lacks a live wire for various reasons, if there is no protection device, the consequences of the lack of phase are very serious. When the small motor starts, it lacks phase, and if there is no load, it will rotate slowly unevenly and heat up at the same time.

If you don't stop the car in time, it won't take long to burn out. If you start with a load, it won't turn up, and it will also burn out.

The reasons for the lack of phase in three-phase motors generally include:

The fuse blows.

Thermal relay action.

Damaged or poor contact.

Check that the line is in good condition.

How to tell if the motor is out of phase?

Listen to the sound, if it makes a buzzing sound, it is generally out of phase.

Use a multimeter to measure the voltage of phase A, phase B and phase C respectively, if the three-phase voltage is unbalanced, it is generally a lack of phase.

Electrical knowledge: the three-phase motor will automatically stop when the contactor is out of phase, and the principle is actually very simple.

Will the three-phase motor run in the case of lack of phase, and will the motor burn out?

The lack of phase of the three-phase motor will cause the motor winding to overheat and burn, and the consequences are serious.

Consequences of phase loss of three-phase motor.

The so-called three-phase motor is out of phase operation, that is, the three-phase motor operates under the one-phase open circuit of the power supply or the one-phase open circuit of the stator winding. For example, the one-phase fuse is blown or the contact is poor, the one-phase contact in the circuit breaker, disconnector, cable head and wire is loose, and the one-phase disconnection in the stator winding of the motor may cause the motor to run out of phase. According to statistics, the vast majority of accidents in the burning windings of three-phase asynchronous motors are caused by the lack of phase operation.

1. The three-phase motor is missing phase when running, if the load does not change, that is, the two-phase winding bears the work of the original three-phase winding, the current of the two-phase winding will inevitably increase, resulting in the indication value of the ammeter rising or zero (if the one-phase disconnection of the ammeter is just installed, the current indication is zero), the temperature of the motor body increases, the vibration increases and the sound is abnormal, and the motor coil will be burned out for a long time.

2. The three-phase motor lacks phase when it is no-load, and the two-phase electricity can drive the motor to run for a long time, but the current will increase to close to the rated value of the motor and the motor sound is abnormal.

3. The three-phase motor lacks a one-phase power supply, and cannot be started because it cannot produce rotational torque. Once it is found that the three-phase motor is running out of phase, the standby unit should be started immediately, the faulty motor should be quickly removed, and the maintenance personnel should be informed to come to check the cause and take countermeasures.

Three-phase motor, no phase loss operation. The lack of phase is not the burning of the control parts, but the motor itself. Phase loss protection is the most important protection of the motor.

The lack of one phase of the three-phase motor will cause the other two-phase current to become larger, the motor does not rotate or rotates very slowly, the motor coil will burn out after a long time, because the contact capacity of the solid state relay is relatively small, the lack of phase causes the other two-phase current to become larger, and the relay contact capacity is insufficient, which will cause burnout.

1. If the motor is in a stationary state and starts out of phase, the motor will vibrate seriously and make a "buzzing" sound, and the motor cannot start normally.

2. If the motor is running and there is a sudden lack of phase, the motor will have a sudden decrease in speed, the motor will overheat, etc., and the power supply should be cut off immediately, otherwise it is easy to burn the motor.

If the three-phase motor lacks one phase, the current of the missing phase motor increases, the running time is longer, the motor will burn out, and the solid state relay will burn.

If the three-phase motor lacks one phase, the original stationary motor will not be able to start, making abnormal sounds.

The motor that has been running has abnormal rotation, strange sound, heating, such as cutting off the power supply without a protection device, burning out the equipment.

The motor will not work if it is out of phase, and it will hum. As for the consequences, the relay will not be burned out for a short time. FYI.

After the lack of one-phase electricity and the imbalance of three-phase electricity consumption will lead to a sharp increase in current, the coil will overheat, and the motor will be burned.

Three-phase electric phase loss, the motor hum can not be started, the lack of phase in operation motor operation is weak, overcurrent and overtemperature, the protection circuit action stops, if the protection circuit is not in place, the motor winding insulation is burned, and the motor is damaged.

If the closing time is long, it may damage the electrical equipment, because the lack of phase will not be able to bring up, and the machinery will heat up and will be destroyed.

The second is the consequence of the lack of phase in the running motor. (1) If the three-phase AC motor is stopped. It is due to the lack of a phase line (assuming the lack of a C phase); Only phase A and phase B remain, although the motor windings are added to two.

The three-phase motor cannot start and run without phase.

Several situations and consequences of the lack of phase operation of the three-phase asynchronous motor: when the three-phase asynchronous motor lacks one phase of electricity, the motor will not be able to start, and there is a strong "hum" sound.

If the motor lacks a phase power supply during operation, although the motor can continue to rotate, the speed will decrease. If the load is not reduced, the stator current of the motor will increase, causing overheating. At this point, the operation must be stopped immediately, otherwise the motor will be burned.

This rotating magnetic field cuts the rotor winding, thereby generating an induced current in the rotor winding** The sub-winding is a closed path), the current-carrying rotor conductor will generate electromagnetic force under the action of the stator rotating magnetic field, thereby forming an electromagnetic torque on the motor shaft, driving the motor to rotate, and the motor rotation direction is the same as the direction of the rotating magnetic field.

How it works:

When a symmetrical three-phase alternating current is introduced into the three-phase stator winding, a rotating magnetic field is generated that rotates clockwise along the circular space of the stator and rotor at a synchronous speed n1. Since the rotating magnetic field rotates at n1 rotational speed, the rotor conductor is stationary at the beginning, so the rotor conductor will cut the stator rotating magnetic field and generate an induced electromotive force.

Since the two ends of the rotor conductor are shorted by short-circuit rings, under the action of induced electromotive force, the induced current in the rotor conductor will be basically consistent with the direction of the induced electromotive force. The current-carrying conductor of the rotor is subjected to an electromagnetic force in the stator magnetic field (the direction of the force is determined by the left-hand rule). The electromagnetic force generates an electromagnetic torque on the rotor shaft, which drives the rotor to rotate in the direction of the rotating magnetic field.

Can a three-phase motor rotate without phase? When the three-phase asynchronous motor is out of phase, the speed will decrease. If the load is light, the rotation can be maintained.

If the load is heavy, it is possible to stop. When the phase is missing, there is no rotating magnetic field, so it cannot be activated. If the phase loss operation can be found in time, the motor will generally not be burned out.

If the motor is out of phase when it is started, it will emit noise and the motor will not start. If the motor is out of phase during operation, the motor will also make noise, and the motor will continue to run due to inertia, but if it continues to run without stopping immediately, the windings of the motor will burn out. Therefore, the control circuit of the motor is generally provided with phase failure protection.

When the motor is in a phase-out state, the motor will quickly burn out.

The reason is as follows: when the motor is running in two phases, the stator magnetic field has a three-phase rotating magnetic field that becomes a single pulsating magnetic field, and this pulsating magnetic field can be decomposed into two rotating magnetic fields that turn to the opposite direction, in which the positive torque generated by the forward rotating magnetic field makes the motor continue to run, and the reverse torque generated by the reverse rotating magnetic field will offset a part of the positive torque, so the torque of the motor is much lower than the original. When the two phases are running, there is no current in the phase that is missing, and the current of the other two phases increases, although the motor can still run, but the speed decreases and the current increases, which heats up the motor and is easy to burn out the motor winding. Therefore, the motor is not allowed to run out of phase for a long time.

If it is unloaded, it will still turn after starting, but the sound is abnormal. If it is under heavy load, it will not turn and there will be a buzzing sound. Due to the lack of phase, the current will rise sharply, and if there is no phase loss protection circuit, the motor will burn out.

Hello, according to your problem description, the solution provided to you here is as follows: the lack of phase of the motor is the cause of the phase failure: 1. The fuse circuit of the power supply circuit of the motor is in poor contact or is mechanically damaged, resulting in the fuse of a certain phase.

2. The specifications of the three-phase fuse in the power supply circuit of the motor are different, and the fuse with small capacity is burned. According to the power of the motor, it should be replaced with a fuse of the same specification. 3. The contact of the switch (isolation switch, rubber cover switch, etc.) and contactor in the power supply circuit of the motor is not in good contact (burned or loose).

Repair and adjust the dynamic and static contacts to make them in good contact 4. Find out the broken wire and connect it firmly. 5. False welding between the windings of Huai or the motor, resulting in poor contact.

Carefully inspect the motor winding connection line and weld it firmly. Fault phenomenon: [Lack of phase] One phase of the three-phase circuit of the brushless motor or brushless controller cannot work.

Phase loss is divided into main phase absence and Hall phase loss. It is manifested as the motor shaking and cannot work, or the rotation is weak and noisy. It is easy for the controller to burn out when it is in the state of phase loss.

One of the three-phase circuits of a brushless motor or brushless controller cannot work. Phase loss is divided into main phase absence and Hall phase loss. It is manifested as the motor shaking and cannot work, or the rotation is weak and noisy.

It is easy for the controller to burn out when it works in a phase-out state. If the three-phase motor lacks a live wire for various reasons, it is called phase loss. If there is no protective device, the consequences of phase loss are very serious.

When the small motor starts, it lacks phase, and if there is no defeat to shout the load, it will rotate slowly unevenly, and at the same time heat, if it is not stopped in time, it will burn out in a long time. If you start with a load, it won't turn up, and it will also burn out. If the larger motor starts out of phase, it will buzz and have to stop quickly.

Small motors are most likely to lose phase, because some starting devices are poor, the contact is not good, or the use of ordinary fuses has a fuse. If the contactor is started and protected by a thermal relay, the contactor can protect two of the phases from disconnecting themselves in the event of a phase loss, and the thermal relay can cut off the contactor in the event of overcurrent.