Causes and Solutions for Electric Heater Not Stopping Heating Normally During Operation:
Fault Cause Analysis:
Fault Handling Method:
The thyristor in the voltage regulation module is short-circuited and directly conducts, not controlled by the control signal.
Power off, check the thyristor for quality and replace it.
The control signal from DCS is always at maximum, and the control signal cannot be adjusted.
When DCS always gives the maximum control signal, the thyristor in the voltage regulation module remains in a conducting state, and the electric heater heats at maximum power, unable to change output power with temperature changes. Notify instrument personnel to check the DCS signal system.
The main contactor's main contacts are welded shut.
If the main contacts of the contactor are welded shut, notify the process to reduce the electric heater's power to the minimum, then disconnect the main circuit breaker QF1 and replace the main contactor.
The over-temperature controller has an internal fault and does not issue an over-temperature alarm.
Notify the process to have instrument personnel check the over-temperature controller, with electrical personnel assisting.
The medium temperature sensor is faulty and cannot detect the medium temperature. Thus, the signal sent by the medium transmitter to DCS is the minimum signal, so DCS will send the maximum signal to make the electric heater continue heating.
Notify the process to have instrument personnel check the sensor.
The medium temperature sensor is faulty and cannot detect the medium temperature. Thus, the signal sent by the medium transmitter to DCS is the minimum signal, so DCS will send the maximum signal to make the electric heater continue heating.
Notify the process to have instrument personnel check the sensor.
