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Principle of Relay Control System for Diesel Generator

Dec. 26, 2022

The diesel generator relay control system is composed of three parts: diesel engine, AC brushless synchronous generator and control panel. The diesel engine is equipped with automatic starting and automatic stopping actuators, and the control panel is equipped with automatic starting device and switching control device. The control panel is connected to the unit through cables. The sensor is the input device of the diesel engine control system. It converts various working condition information of the diesel engine into electrical signals and sends them to the electronic control unit to monitor the status of the diesel engine and make it in the best working state. There are many sensors for diesel engine, mainly including speed, lubricating oil pressure, oil temperature, water temperature, liquid level, etc. The speed sensor is the same as the sensor used in the electronic speed control system.


diesel engine generator


The control system of automatic diesel generator is mainly composed of mains power monitoring, self starting controller, mains power switching circuit and oil electromechanical switching circuit. Relay logic control is adopted for mains power monitoring, oil electromechanical monitoring, switching circuit and self starting controller. Under the emergency control state, when DS is rotated to the working state, there is no electric plate at both ends of RS1, RS2 and J coils, the voltage at both ends of their normally open contacts is about DC 24V, the voltage at both ends of DCT full speed coils is DC 24V, and there is no voltage at the starting coils; When starting, the voltage length of RS1, RS2 and J coils and DCT coils should be about 20V.


The main functions of the control system include automatic start, automatic speed increase, automatic power supply, automatic stop, etc.


Automatic starting and automatic power supply: when the mains power is interrupted, the mains power supply circuit will be cut off immediately by the mains power switching circuit. At the same time, the mains power monitoring circuit will make the starting motor run through the self starting controller, thus starting the diesel generator. After the start is successful, connect the oil circuit solenoid valve and open the oil circuit to drive the throttle handle to move in the speed increasing direction. Under the action of the speed increasing limit controller, the diesel engine works at the rated speed. At this time, the diesel generator outputs the rated voltage under the action of the automatic voltage regulator. Then, the diesel electromechanical switching circuit is connected, and the diesel generator starts to supply power to the load. The electronic governor can also select the degree of unevenness (speed drop) according to the needs of the diesel engine application. In case of no difference adjustment, the electronic control system will eliminate the difference between the set speed and the actual speed caused by the load change, so that the diesel engine can maintain the original set speed. According to the needs of the unit, the non-uniformity potentiometer can also be adjusted to make the speed regulation system obtain the set steady speed regulation rate.


Automatic shutdown after mains power recovery: after mains power recovery, under the action of mains power monitoring circuit, first cut off the power supply circuit of diesel engine, then put the mains power switching circuit into operation, and the load is powered by mains power. At the same time, the self starting controller makes the stop electromagnet act to control the accelerator of the diesel engine. The diesel engine runs at low speed first, and then automatically stops. The automatic diesel generator uses relays and contactors to form an automatic control system. The number of components required is large, the control circuit is complex, the working reliability is poor, and the failure rate is high. The governor and the diesel engine form an automatic regulation control system. The change of the external load causes the change of the diesel engine speed. After a certain transmission ratio, the governor has a speed change, and the speed change of the governor generates an output signal. The transmission ratio directly acts on the oil pump gear rod, causing displacement of the gear rod. The displacement also causes the change of the fuel supply, which ultimately affects the speed of the diesel engine and plays the role of automatic speed regulation.


Starlight Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to sales@dieselgeneratortech.com we will pay highly attention on your question.

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