Reprint–Review of a certain electric door defect

Source:Thermal control maintenance class Thermal Control Maintenance Class Lecture

Question: One day, # 3 units are connected to the extended electric door MBV-34. The host computer displays the valve status green, butThe manual automatic switching handle failed to return to the automatic position,At this time, the operator issues a start command.

Will the valve move? What status does the host computer display? Will the motor keep heating up and burn out?

Answer:

Run and send the open command. After the open command is sent, the valve first flashes red (the open contactor is closed), and after a while it remains green. Because the DCS command is issued, the valve flashes red, but the closed position switch has not been disengaged; then the DCS command disappears (after 45 seconds, the full open signal is not received, a start failure signal is issued, and the open command is reset), and the valve still turns green. (The valve has not moved, nor has it reached the middle position, half red and half green). The local valve is not moving.

The spindle does not rotate, the counter will not act, and the torque will not act; if the DCS open command contact cannot be reset, the Only thermal action is used to stop the motor from idling. In this case, The motor will not keep heating until it burns out.

Open in position—red flashing—forward rotation auxiliary connection closed

Close in place – flashing green – reverse auxiliary connection to close

Half red and half green – both non-fully open and non-fully closed signals are received gray – fully open and fully closed signals are received

(power supply, external power supply), the color of thermal effect does not change to gray