1. The frequency of the three-phase asynchronous motor 60HZ, 50HZ, if then in power use, what kind of phenomenon will occur?

n = 60f / p ，f is the frequency， n is the speed，P is on the number of Poles

60 to 50, speed will be slow to increase iron consumption, the current increases, power reduced, the electrical heating, do not use a full load.

2. Driven three-phase asynchronous motor rated load of work, if the power supply voltage drops too much, tend to heat or electrical burn, and why?

  Driven three-phase asynchronous motor rated load of work, if the power supply voltage drop and current increase, not because the same motor power, but because the result of reducing the armature reaction; at this time of the motor power is usually a slightly smaller, the torque is also slightly smaller than the points. As a result of lower terminal voltage, its potential is bound to reduce the resistance, the current increased, reached a new point of balance. If the voltage drop in the more general will increase the number of current, resulting in burning motor.

3. How is the three-phase asynchronous motor angle to connect the star thing, what are the advantages and disadvantages?

  Triangle: both three-phase winding, followed by three-phase power supply, the property a triangular shape winding schematic; 

  Astrocytoma: three windings with the first access point as a neutral, three rear three-phase power supply then. Winding was "Y" shape. 

  Triangle big advantage is the output power, high starting torque, starting current major shortcomings. Winding specifications for the needs of the larger wire. 

  Advantage of current star start small, but power and torque is also small. 

  The same motor output power: then into then into a star-shaped angular is 3 times 

4. Three-phase asynchronous motor running at rated voltage, the load increases, that is, increased resistance to torque, speed will be reduced accordingly, but very subtle, so that the motor stator rotor speed than the speed difference between the rotating magnetic field to increase the system impedance  decline in three-phase stator current increases, the corresponding induced current in the rotor also increases. Of course, the increase in load power load is also increased.

5. Three-phase asynchronous motor has two categories, one is the rotor cage, and the other is the rotor winding. Three-phase asynchronous motor current is rated current of 4-7 times more power 10KW motor can not directly start, to be used in step-down start of Wound Rotor resistance starting string, FM starting deceleration. three-phase asynchronous motor speed are as follows: speed regulator, rotor speed control loop resistor string, Frequency Control, weak magnetic governor, is the value according to the functions of sub-torque value for power and speed governor.

6.Speed regulator for small power motor, because its output torque and the stator voltage is proportional to the square, speed regulator, the motor threshold of the same slip. Rotor speed control loop resistor string is a very speed , you can get the maximum starting torque and braking torque, so commonly used in the cable car system, in the heavy lifting to get the most when the starting torque, heavy decentralization can be better when the braking torque. Frequency speed there are two types of pressure-frequency than the speed value, which value speed torque, output torque in the same circumstances can change the speed, the speed in the more ideal way, is now general industrial. Another stator voltage is the same, but the frequency above the nominal frequency adjusted at the motor or speed (higher than the rated speed), but its smaller output torque, the method used to load air pumps are value - Power Control.