Three phase asynchronous motor overload cause 5

Check the external power supply voltage, if the voltage is too low, this may be caused by this.

The maximum torque T of the motor is proportional to the square of U, and the square reduction of the starting torque T and U is proportional to the reduction, the asynchronous motor is very sensitive to the fluctuation of the power supply voltage, and the running time, if the voltage drops too much, will reduce its overload capacity and starting torque, and even the phenomenon that it does not understand the load or cannot start at all

It's a big load, a small horse-drawn cart.

An overload of a three-phase asynchronous motor is when the current flowing through the motor exceeds the rated current for a certain allowable time. For a simple example, a 380V, three-phase asynchronous motor has a rated current of 15A, but in actual use, it can make the current flow through 20A, and the maximum allowable time can only be 1min. So the overload capacity of the motor is 20 15 133%.

1min。The actual overload capacity of the motor is relatively strong, often reaching 2 times the rated current, and the duration is 1min.

The better the overload capacity.

The performance of the motor is also relatively good.

Summary. Tripping, overloading, automatic power outage.

The three-phase asynchronous motor runs at full load, and the power supply voltage drops.

Tripping, overloading, automatic power outage.

Question 5: Let's take a look, thank you! c

Summary. The excitation current and the main magnetic flux are not a corresponding relationship, and after the transformer is manufactured, its main magnetic flux is dead and cannot be changed. When the excitation current is large enough (core saturation), the main magnetic flux can be approximately unchanged (it can be understood that a tube of 1 square meter can pass through 1 square meter of water at most, and you think that square meters can not pass), which is the saturation state of the iron core.

The voltage of the three-phase asynchronous motor changes, whether it can run under load.

Hello, I am helping you to inquire about the relevant information and will reply to you immediately.

Hello, I am helping you to inquire about the relevant information and will reply to you immediately.

The three-phase asynchronous motor runs under a certain load, if the voltage of the electric jacket impulse source decreases, the tremor torque of the motor remains unchanged (because the load does not change), the current increases, and the speed decreases. Punching".

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Analyze how the transformer voltage changes, the main flux and excitation current.

Analyze how the transformer voltage changes, the main flux and excitation current.

The excitation current and the main magnetic flux are not a corresponding relationship, and after the transformer is manufactured, its main magnetic flux is dead and cannot be changed. When the excitation current is large enough to resist the attack to a certain extent (the core is saturated), the main magnetic flux can be approximately woven unchanged (it can be understood that a tube of 1 square meter can pass through 1 square meter of water at most, and you think that the square meter is not passable), which is the saturated state of the iron core.

Who asked you this.

Who asked you this.

The direction of the main magnetic flux is determined by the direction of the intake of the excitation coil, and the direction of the main magnetic flux can be changed by changing the direction of the excitation current.

Three-phase asynchronous electric machine does not exceed the rated current, so it is not overloaded? Hello dear,!The overload capacity parameter of the three-phase asynchronous motor shall not be greater than the times of its rated current, of course, the overload capacity of the small three-phase asynchronous motor is greater than the overload capacity of the medium and large three-phase asynchronous motor.

When the overload current of the motor is greater than the rated current value, the motor will heat up and get hot, and the insulation resistance of the motor winding will be damaged or will be broken down at this moment, so at this time the various protectors of the main circuit will act to cut off the power supply. the overload capacity of the asynchronous motor; It is that the current passing through the motor exceeds the rated current within a certain permissible time. To make a wide analogy; The rated current of the 11 kW three-phase asynchronous motor is 22A, but the load current can flow through 25-27A in normal use, and the maximum allowable overcurrent time is 1 minute.

So the overload capacity of the motor is 27 22 = 122% 1min. In the design and manufacturing, the overload capacity of the motor is relatively large, and some can reach up to 2 times the rated current, and there is no problem within 1 minute. But not too long, otherwise it will burn the motor windings.

Dear, hello, yes, the overload capacity parameters of the three-phase asynchronous motor shall not be greater than times its rated current, of course, the overload capacity of the small three-phase asynchronous motor is greater than the overload capacity of the medium and large three-phase asynchronous motor. When the overload current of the motor is greater than the rated current value, the motor will heat up and be hot, and the insulation resistance of the motor winding will be damaged or will be broken down at this moment, so at this time the various protectors of the main circuit will act to cut off the power supply. The overload protection of three-phase asynchronous motor is also called overcurrent protection.

When the actual load of the three-phase asynchronous motor exceeds the rated load, it will cause the current in the reed hole in the three-phase winding of the motor to increase. When the current exceeds the rated current or is too large, it may cause the motor winding to burn out. In order to ensure that the actual current of the motor does not exceed the allowable rated current, an overload protection device is used for excavation.

Commonly used overload protection devices include thermal relays, special protectors for motors and overcurrent protectors. I hope my reply can help you, if you have any follow-up questions, please feel free to ask me, I will reply to your <> as soon as possible

Summary. Hello, dear dear, I'm glad to answer for you (2) Three-phase current unbalance. This is the reason that the three-phase winding has misgrounding, short circuit or poor contact, etc., if the sound is very dull, it means that the motor is seriously overloaded or out of phase operation.

3) The core is loose. The motor loosens the core fixing bolt due to vibration during operation, causing the core silicon steel sheet to loosen and make noise The reasons for the low speed of the three-phase motor are: 1. The load is too heavy, the mechanical resistance is 2, the motor is disconnected in one phase 3, and the power supply voltage is low&194;4. Short circuit between turns of stator winding or internal disconnection of winding (phase loss operation), &194;Overheating or smoke is probably a short circuit between turns.

The three-phase asynchronous motor has low speed, poor load capacity, and noise during operation.

Hello, dear dear, I'm glad to answer for you (2) The three-phase current is uneven with Biheng. This is the reason that the three-phase winding has misgrounding, short circuit or poor contact, etc., if the sound is very dull, it means that the motor is strict and hidden heavy overload or lack of phase operation. (Let the front 3) the iron core loosen.

The motor loosens the core fixing bolt due to vibration during operation, causing the core silicon steel sheet to loosen and make noise The reasons for the low speed of the three-phase motor are: 1. The load is too heavy, the mechanical resistance is 2, the motor is disconnected in one phase 3, and the power supply voltage is low&194;4. Short circuit between turns of stator winding or internal disconnection of winding (phase loss operation), &194;Overheating or smoke is probably a short circuit between turns.

Noise generated by the midstream of the air vortex. It is due to the fact that the air flow generated by the rotating parts on the fan or rotor encounters obstacles when rotating, which causes the air path cross-section to change drastically or the sudden change in the direction of the air flow and the noise generated by the eddy is envied There are so many possibilities, one, the load is too large, and the solution is to choose a larger capacity motor or reduce the load. Second, the brush and slip ring are in poor contact.

The solution is to adjust the pressure of the brush and improve the contact surface between the brush and the slip ring. Third, the starting rheostat of the wound rotor motor is not in good contact. The solution is to repair the connection of the rheostat.

The following is the accumulation fault phenomenon and maintenance method of the common base of the three-phase asynchronous motor: 1. The motor can not be started by Senfenghuai Fault cause analysis: Reason 1:

The power supply has a loss of voltage or undervoltage fault. The power supply voltage loss is mainly due to the short circuit and ground fault of the motor and its control circuit, resulting in the power tripping; The main reason for the undervoltage of this friendly source is that the starting device is faulty.