Causes and solutions for electric heater not stopping heating normally during operation:
Fault cause analysis:
Fault handling method:
The thyristor in the voltage regulating module is broken down and directly conducts, not controlled by the control signal.
Power off, check the thyristor for quality and replace it.
The control signal given by DCS is always the maximum signal, and the control signal cannot be adjusted.
When DCS always gives the maximum control signal, the thyristor in the voltage regulating module is always in the conducting state, and the electric heater heats at maximum power, unable to change output power with temperature. Notify instrument personnel to check the DCS signal system.
The main contact of the main circuit contactor is stuck.
If the main contact of the contactor is stuck, notify the process to adjust the power of the electric heater to the minimum, then disconnect the main circuit breaker QF1 and replace the main circuit contactor.
Internal fault of the over-temperature controller, no over-temperature alarm issued.
Notify the process to have instrument personnel check the over-temperature controller, with electrical personnel assisting.
The medium temperature sensor is damaged 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.
