Thyristor SMC contactless pressure reduction starting circuit

The SMC non-contact pressure reduction starting circuit consists of a main circuit and a control circuit. The circuit includes power control switch QF, SMC-1 voltage
regulator, thermal relay FR and three-phase AC motor Ml, etc.
The control circuit includes control transformer TC, control buttons SB1 and
SB2, cooling motor M2, controller SMC-Z and
contacts of thermal relay FR, etc. The thyristor SMC contactless
voltage reduction starting circuit is shown in Figure 4-40.
    The SMC controller uses thyristor voltage regulation and comes with
a start-stop controller in the equipment. Its voltage adjustment range is 200-600V
. The SMC controller with a frequency of 50Hz and a current of 1 to 97A
can be equipped with a soft stop interface. It can also choose a
protection module with a built-in varistor to prevent the thyristor
from being impacted by surge voltage. These components and connectors
are assembled with the SMC controller. The SMC controller has the following
three starting methods to choose from: soft start, current-limited start
and full-voltage start.
    During the starting process of the SMC controller, the non-conducting part will generate useless heat, and the heat sink attached to the lower part must be installed vertically. 68A
and 97A controllers should be equipped with fans, and the air volume should not be less than 1.64X lO-ad/min. The cooling fan can be connected to terminals 1 and 4 of the terminal board, and
terminals 2 and 3 are short-circuited to the control box where the iSMC is installed. The upper part should be opened with blinds, and its net area should not be less than 140cmz.
    Turn on the power switch QF. The control transformer is powered, its secondary (side) supplies power to SMC-2, and the circuit enters the hot standby state. , when starting,
press button SB2, the contacts (50-60) are closed, and the cooling fan starts running. At the same time, SMC-1 is controlled and provides power to the motor. The motor
starts smoothly and gradually enters the rated working condition. When shutting down, press button SB1, SMC2 issues a shutdown command, SMC -1 is controlled, and the electronic
voltage regulator is cut off. The motor loses power and stops working. '