Comparison and analysis of the characteristics of the start-up mode of Customized electric dc motor
1.13 Starting from the lotus Transformer
Since the start of the self-lotus Transformer is the motor start, through the choice of the middle plug of the self-lotus Transformer relief start, when the motor operation is stable or the current reaches a certain value, remove the self-lotus Transformer, into the normal operation mode. The starting current of the self-root Transformer is relatively small during the start-up process, but there is a secondary impact, which has a certain impact on the power grid and electrical equipment.
1.14 Variable resistance soft start
The variable current resistance soft start includes the thermal resistance start and the liquid resistance start. The partial pressure drop is mainly shared by concatenating the variable liquid resistance in the loop. As the starting time passes, the pressure drop on the variable resistance decreases, and finally the high voltage motor starts smoothly. The starting characteristic of variable resistance starting mode is better in the starting process, but it is not suitable to start frequently.
1.15 Magnetron soft start
Magnetron soft start is to adjust the flux of the reactor by adjusting the conduction angle of Silicon controllable, so as to change the voltage of the motor end and achieve the purpose of stable start of the motor. However, the technology is not mature enough and is not widely used at present.
1.16 Frequency conversion soft start
Frequency conversion soft start is the use of Silicon controlled components to convert power supply into another frequency power supply, mainly using the "AC-direct-intersection" method(VVVF frequency conversion or vector control frequency conversion, direct torque control frequency conversion), The power supply of power frequency AC is first converted into DC power supply through rectifier, and then DC power supply is converted into AC power supply that can be controlled by frequency and voltage. Now, Matrix intersection frequency conversion is also under development. With the development of technology, frequency conversion soft start is the most promising type of high voltage motor.
