Large drum type washing machine electric controller

The figure shows the electric controller circuit of a large drum-type washing machine . The controller consists of a pulse generator, counter, relay control circuit, step-down rectifier circuit, etc. The buck rectifier circuit provides DC voltage for the entire controller.

The pulse generator is a multivibrator composed of IC 1 (555) and R2, R1, C1, etc., and its oscillation period is T≈0.693(R1 R2)C1. Counter IC2 uses the decimal counting/pulse distributor CD4017 , which uses the output pulse of IC 1 as the clock signal. The Y0~Y9 terminals continuously cycle the high level with the same output period as the counting pulse period. The output Y0, Y4, Y5, Y9 controls the switches of BG1, BG2, and BG3 in sequence, and activates relays J1, J2, and J3, thereby controlling contactors 1C and 2C to connect to the three-phase AC motor power, and complete the washing function according to the washing machine sequence.

This controller can realize the same forward rotation → stop → reverse rotation → stop functions as the mechanical contact controller.