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Discussion induction motor fault diagnosis

Date:2016-04-21View:398

Three-phase asynchronous motors in vertical and more continue to use the device occupies an important significance in people's lives. Discussion phase induction motor common electrical failure and maintenance, can reduce the loss of three-phase asynchronous motors motor electrical fault caused more conducive to promoting the use of three-phase asynchronous motors in life. From the three-phase induction motor fault characteristics and common fault detection method, it discusses the phenomenon of induction motor common electrical failure analysis, to provide reference for fault repair three asynchronous motor.

First, the main characteristics of three-phase asynchronous motors failure

Three-phase asynchronous motors failure and motor wear, aging, fatigue has a great relationship, according to the situation of failure, summed up the failure of three-phase asynchronous motors are mainly the following characteristics: First, potential, motor running process because of lubrication problems lead to wear of the motor, when after severe wear, parts motor parameters exceeding the permitted value, this is operated, the motor will have some potential failure. Second, gradual onset, wear three-phase asynchronous motors, fatigue, aging is developed over time, damage parts occurs gradually, damaged parts may be happening slowly, so it has a gradual onset. Third, ambiguity, because when the motor's internal and external environment is different, so causing damage to the motor with a certain randomness, have resulted in the failure criterion for judging dispersible. Fourth, the diversity in the process of equipment operation, since the wear, fatigue, corrosion occurs on the part of the aging time, the damage caused by parts are different, the fault is not caused by the same, for example: the motor rotor imbalance rotor shaft bending, bearing wear, aging, rotor bar failure. These four points are the main features of the three-phase asynchronous power-failure.

Second, the three-phase asynchronous motors common electrical failure Phenomenon

(A) the stator winding grounding

1. Symptom

Stator winding grounding stator winding is connected with the case, the winding current increases caused by the grounding, then often lead to winding a lot of heat, causing phase short circuit, so that the motor can not be normal operation, while in the process of failure with a lot of noise .

2. Analyzing Method

Stator winding grounding fault diagnosis methods are the following: First, observation, to observe the winding end and the notch for cracks and charred case, if there is a description of this part is the location of the fault; secondly, check test pencil, test pencil check the motor housing to see if the neon tube lights, if lights up, there is the case of stator winding grounding occurred; Third, check with a multimeter, check the terminal and the housing of the three-phase windings

Between resistance, resistance is 0, then the winding shorted.

3. The repair method

Fix the stator winding grounding faults: find the point of failure, and then eliminate ground, if it is judged a failure to produce, but the core was observed at the notch no insulation breakdown, charred, etc., then the access point in the tank, it needs to continue to be checked If found no serious burn phenomenon, then between the ground and the core of the wire, put insulating material, and can be painted.

(B) of the stator winding short circuit

1. Symptom

Stator windings open circuit is a coil wire insulation damage caused, this time turns directly connected, the motor current is large, the coil will get very hot when the disconnection turns a little while, the motor rotation can still function properly, but current increases, resulting in inconsistent three-phase current, which would make the motor torque decrease, when more turns short circuit, usually burn out the motor, the motor can not start.

2. Analyzing Method

Stator winding short circuit fault diagnosis includes the following ways: First, the external observation method, usually the motor apart and observe the color of the stator windings breaking point often presents black scorch marks, darker, insulating paint zoom black, fragmentation occurs carbonization phenomenon; Second, feel the temperature rise method, which is mainly the use of a short circuit will produce a lot of heat principle, the motor no-load operation for about 10 minutes, then off, quickly disassemble the motor, there are hand feel the temperature significantly higher places where these places are short circuit occurs; Third, universal table to check the resistance is found that the resistance is zero or very small, compared to a short circuit. Fourth, the resistance measurement method, the resistance values were measured more phase windings, then, there is a fault in a smaller value as compared to normal.

3. The repair method

Stator winding short circuit fault repair is usually to find out after the short circuit, the number of turns for a small, insulated, when the number of turns more time, winding replacement.