Reasons and Solutions of 300KW Diesel Generator Without Voltage

(1) The excitation voltage is too low (2% lower than the rated voltage at rated speed) and cannot be excited.

Solution: Use 3-6V dry battery or storage battery for magnetization. During magnetization, pay attention to connect the positive pole to F + and the negative pole to F -.

(2) Wrong wiring.

Solution: check carefully and connect correctly according to the wiring diagram

(3) Magnetic field coil open circuit.

Solution: reconnect the open circuit, solder it firmly, and wrap it with external insulation.


(4) Loose or poor contact of each terminal of excitation device.

Solution: clean the connector and connect it properly.

(5) Inaccurate meter.

Solution: check the meter regularly.

(6) Partial short circuit or grounding of field coil.

Solution: replace the magnetic field coil.

(7) Generator armature coil open circuit.

Solution: find out where the open circuit is and re weld and wrap it.

(8) Generator armature coil short circuit.

Solution: short circuit will cause serious heating, and the coil should be replaced.

(9) Rectifier diode damaged varistor overvoltage protection resistance capacitance damaged.

Solution: replace the rectifier and replace the resistance capacitance protection parts.

(10) The air gap of reactor is too small after maintenance.

Solution: increase the air gap.

What are common reason of diesel generator low voltage? How to solve the problem?

(1) Cause: the engine speed is too low. Treatment: adjust the engine speed to the rated value.  

(2) Cause: the resistance of excitation circuit is too large. Treatment: reduce the resistance of the field rheostat to increase the excitation current. For semiconductor excitation generator, check whether the additional winding connector is disconnected or wrongly connected.  

(3) The exciter brush is not in the neutral line position, or the spring pressure is too small. Treatment: adjust the brush to the correct position, replace the brush and adjust the spring pressure

(4) Cause: some rectifier diodes are broken down. Treatment: check and replace the broken down diode.

(5) Cause: there is short circuit or grounding fault in stator winding or excitation winding. Handling: check the fault and clear it.  

(6) Cause: the contact surface of the brush is too small, the pressure is insufficient, and the contact is poor. Treatment: if the surface of the commutator is not smooth, polish the surface of the commutator with emery cloth or adjust the spring pressure at low speed.

What are the main factors affecting the voltage of diesel generator?

Because the diesel generator uses the engine speed regulation rotation to drive the generator to generate electric energy, and it must be able to start power generation in a short time. Therefore, sometimes the voltage is not as stable as the power grid, which may have some impact on the diesel generator set and operation in use. 

1. Unstable speed causes unstable voltage of generator set.

2. The damage of the voltmeter causes the false image of voltage instability. Of course, most generator sets now use intelligent displays, so this phenomenon does not exist.

3. The excessive load borne by diesel generator set is also easy to lead to voltage instability.

4. The damage of voltage regulator components causes the voltage instability of generator set.

5. The poor flow of fuel pipe of generator set causes unstable engine speed and unstable voltage, which can be attributed to point 1.

In addition, the unstable load of the equipment will also cause the voltage instability of the diesel generator. In view of this phenomenon, when using the diesel generator set, it is good to have a specially assigned person to watch and regularly maintain it, so as to ensure that the above phenomena will not occur, and ensure that all parts of the generator set are normal and intact, so as to ensure that the diesel generator set is under normal and stable voltage.

Dingbo power is a professional generator manufacturer and diesel generator set manufacturer. Its products include Yuchai generator set, 300kW generator set, Cummins generator set, Volvo generator set, Perkins generator set and Weichai generator set. Dingbo provide domestic and imported generator prices and generator set prices.

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