The Output Voltage of The Diesel Generator is Lower Than The Rated Value

With the advancement of technology, diesel generator sets have gradually become popular as emergency and backup power sources for daily life and enterprise production. Small gasoline generator sets have also begun to enter the daily lives of residents. Although the number of users is increasing, as mechanical equipment, their internal structure is still quite complex. Today, Guangxi Dingbo Power Equipment Manufacturing Co., Ltd., a diesel generator manufacturer, will introduce the reasons and treatment methods for the over - voltage or under - voltage of fully automatic diesel generators:

After the generator set is started and has reached the rated speed, and the field rheostat has been adjusted to the maximum position of "voltage rise", when the unit is running under no - load, if the voltage cannot be set to 1.05 times the rated voltage, it indicates that the output voltage of the generator is too low, which will cause difficulties in parallel operation, grid connection or power transfer.

 

Reasons for low output voltage of the generator:

(1) Inter - turn short - circuit in the rotor winding of the main generator.

(2) Inter - turn short - circuit in the rotor winding of the excitation generator.

(3) Inter - turn short - circuit in the stator winding of the excitation generator.

(4) Damage to the rotating rectifier module and varistor.

(5) Poor contact of the plug - ins of the excitation system components.

(6) The speed of the engine (usually a diesel or gasoline engine) is too low, resulting in too low induced electromotive force in the stator winding of the generator.

 

When the generator set is started and running normally at the rated speed, and the field rheostat has been adjusted to the minimum position of "voltage reduction", when the unit is running under no - load, if the voltage is still set to exceed 1.05 times the rated voltage, it indicates that the output voltage of the generator is too high. The rated voltage of a conventional generator set is 400V, and if it exceeds 420V, it means the generator voltage is high.

 

Reasons for the generator output voltage exceeding the rated value:

(1) The AVR is not working properly, and there is no shunt of the excitation current.

(2) The external voltage potentiometer (located on the power distribution cabinet) is broken.

(3) The current - limiting resistor R1 and its wiring.

(4) The magnetization switch is in the closed position, causing superposition with the self - magnetization voltage and exceeding the voltage regulation range of the AVR.

(5) The US setting of the AVR is improper and needs to be readjusted.

 

The voltage drops after the generator is loaded:

(1) The plug - ins of the excitation system are plugged in incorrectly.

(2) The AVR is not working properly.

 

Reasons for the diesel generator not generating electricity or the output voltage being lower than 100V:

(1) Damage to the stator winding of the main generator.

(2) Open - circuit in the rotor excitation winding of the main generator.

(3) Open - circuit in the stator winding of the excitation generator.

(4) Fault in the excitation system.

 

As a professional diesel generator manufacturer, we always insist on using first-class talents to build a first-class enterprise, create first-class products, create first-class services, and strive to build a first-class domestic enterprise. If you would like to get more information welcome to contact us via sales@dieselgeneratortech.com.