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Fault Analysis of Electromagnetic Switch of Diesel Generator Set

Jul. 31, 2023

Each diesel generator set needs its starter motor to help complete the starting work when it starts. Because the diesel generator set starts frequently, it is inevitable that the starter motor will not have a little Glitch. In this article, Dingbo generator equipment will share with you the maintenance method of the electromagnetic switch that is most prone to failure of the starter motor. I hope it can be helpful to everyone.


electric generator


The electromagnetic switch (or magnetic switch) of diesel generator set is a device used to connect and disconnect the main circuit of starting motor. At the moment when direct current is connected to the electromagnetic switch, the suction coil and holding coil inside the electromagnetic switch generate a large magnetic field. Under the action of magnetic field force, the starter fork pushes the drive gear towards the diesel engine flywheel and gnaws it in; At the same time, the movable contacts inside the electromagnetic switch make contact with the static contacts of the two terminals, thereby connecting the main circuit of the starter. When the direct current is disconnected from the electromagnetic switch, the driving gear returns to its original position under the action of the return spring, and the starter stops rotating.


Common faults and troubleshooting methods of electromagnetic switch of diesel generator set:


(1) The surface of the movable contacts and the two stationary contacts of the electromagnetic switch should be smooth and flat, and there should be no burning phenomenon. If there is burning damage or unevenness, fine sandpaper can be used to grind it flat. The height of the two static contacts should be consistent to prevent the occurrence of poor contact faults.


(2) Use a multimeter to check for open circuits and short circuits in the pull-in coil and holding coil. Under normal circumstances, the resistance value of the pull-in coil (thicker outer wire) should be within O 6-0.80. Between them, the resistance value of the coil (thinner inner wire) should be within o Between 8 and 1. 00. If the measured resistance value is too large or too small, the cause should be identified.


(3) The movable and stationary contacts of magnetic switches are prone to burning during long-term operation, especially during winter when diesel engines are difficult to start. When the contact is burned, it will be difficult for the starter gear (or wheel swing) to gnaw with the flywheel ring gear of the diesel generator set. In this case, the contact shall be polished with fine sandpaper.


Dingbo Power has advanced testing equipment, modern production technology, professional manufacturing technology, perfect quality management system, and strong technical research and development capabilities. It can provide 3KW~2500KW various specifications of ordinary, automatic, four protection, automatic switching, low noise and mobile generator sets, high quality and low energy consumption to meet the diverse power needs of customers, and can also meet users with different voltages and different frequencies. It is required to create a parallel power supply system for multiple units. If you are interested in our product or any question on generator, welcome to send email to sales@dieselgeneratortech.com.

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