What Is the Motor Strip?

Triple-phase asynchronous motor is a type of induction motor. It is a type of motor that is powered by simultaneous access to 380V three-phase AC current (120 degrees phase difference). Because the rotor and stator of the three-phase asynchronous motor rotate The magnetic field rotates in the same direction and at different speeds. There is a slip rate, so it is called a three-phase asynchronous motor. The speed of the rotor of the three-phase asynchronous motor is lower than the speed of the rotating magnetic field. The relative motion between the rotor winding and the magnetic field generates electromotive force and current, and interacts with the magnetic field to generate electromagnetic torque to achieve energy conversion.

Three-phase

Three-phase asynchronous motor consists of fixed

The winding is a component of the motor. Aging, moisture, heat, erosion, foreign body intrusion, and impact of external forces will cause damage to the winding.

I. Classification by motor structure size

large

The three-phase asynchronous motor nameplate data includes the following items.

(1)

1. What faults can cause the gearing of the motor (electric ball) group to start the gear?

Answer: The battery power is insufficient. The battery temperature is too high; the starter motor relay does not work; the starter motor transmission gear and the flywheel ring gear cannot mesh; the starter motor enters the meshing and the diesel engine cannot rotate or is weak; the starter motor does not rotate; the start-up fails; The starting motor cannot be separated;

2. What are the main reasons for AVR damage?

Answer: AVR circuit consists of three parts: rectifier main circuit, voltage detection circuit, and comparison control circuit. Excluding the possibility of damage caused by the original quality of the original electrical components, in the entire AVR circuit, the main circuit and the comparison The operating frequency of the control circuit changes the most. Among them, the rectifier bridge in the main circuit and the transistor in the comparison circuit change more frequently, and the damage ratio accounts for more than 90% of the damage rate of the entire AVR. In view of the fact that the AVR on the imported generator is a non-repairable part, If it is damaged, it must be replaced with a new one. Therefore, we mainly analyze the causes of AVR damage on the generator. It is most important to avoid AVR damage as much as possible. As long as it is used properly, it can increase the life of the AVR. The more stable the generator voltage, the smaller the fluctuation frequency in the AVR; the smaller the switching action of the transistor in the comparison circuit, the smaller the chance of AVR damage; the output load is relatively stable, and the smaller the fluctuation frequency in the AVR, the smaller the transistor in the comparison circuit. The smaller the switching action, the smaller the chance of AVR damage; the more stable the speed of the diesel engine, the smaller the shock of the changing current to the AVR; the frequent "parking" and overload, the difference between the three-phase load is too large to cause AVR damage The most important reason is to choose generator sets with E, F, and C fuel systems. Due to the small frequency variation, the use of AVR will be more reliable.

3. What are the conditions for using two generators in parallel? What device is used to complete the parallel work?

Answer: The conditions for parallel use are that the instantaneous voltage, frequency and phase of the two machines are the same. Commonly known as "three simultaneous". Use a special parallel device to complete the parallel work. It is generally recommended to use a fully automatic cabinet. Try not to use manual parallel. Because the success or failure of manual parallelism depends on human experience. With more than 20 years of experience in electrical work, the author ventures to say that the reliable success rate of manual parallel operation of diesel generators is equal to zero. Never use the concept of manual paralleling of a large power system for a commercial power system to apply a small power system, because the protection levels are completely different.