Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

important 7 generator electrical faults


generator electrical faults are important to find and fix . because the generators consider one of the most important primary energy sources in remote areas. where there are no energy sources from the public electricity grid.

It is also considered one of the backup energy sources that used in emergencies, such as hospitals. exchanges, and sensitive areas. Which does not allow to the power to cut off.

You can read an article on the most important generator malfunctions and how to predict them.

The generators are characterized by their rapid response and ability to work continuously without the need to stop for long periods. However, the generators are exposed to some electrical and mechanical failures that lead to the generator shutdown. In this article, we review the most important 7 electrical faults for generators:

output voltage failure for the generator

One of the most important electrical fault that are widely seen in all generators i

generator AVR

the problem of no voltage coming out of the generator, and this may be due to many reasons.

  1. There is a problem in the voltage Automatic Voltage Regulator (AVR)
  2.  the loss of excitation in the rotor
  3. There is a fault in the stator winding
  4. Fault in rotor rectifier bridge

The solution to this problem lies by

  1. changing the rectifier bridge
  2.  changing the AVR card
  3. giving a constant DC current to the rotor exciting coil
  4. megger on stator winding

generator electrical faults of Sensors

Starter Motor Faults

generator electrical fault Starter motor
Starter motor generator electrical fault

The faults of the starter

motor  are many. But in spite of that, it is easy to discover and fix it, and the starter motor faults are represented in three important points, which are:


  1. Relays fed to the starter chicks (Marsh)
  2. The chisels connected to the starter
  3. The internal coil of the starter (the march)

Temperature sensor fault

There are different types of temperature sensors that connected to generators, and they are divided into 3 main types:

  1. Temperature sensor based on resistance change
  2. sensor based on current change
  3. Temperature sensor based on voltage change

The temperature sensor fault are due to two main reasons, which are damage to the internal components of the sensor or damage to the connecting wires connected to the sensor itself. In the event of a difference in the readings resulting from the sensor, you should re-calibrate it again.

Solenoid electrical fault

Solenoid uses to allow diesel to enter the generator pump until it is combustion and the generator’s motion started. The solenoid consists of a primary coil fed by 24 volts from the generator battery.

Solenoid malfunctions are represented by three main causes:

  1. Solenoids-fed relay damage
  2. There is damage to the solenoid file itself
  3. Damage to the connection wires of the solenoid

Oil pressure sensor fault

There are different types of oil pressure sensors that are connected to generators and it also, divided into tree main types:أعطال الكهربية لحساس ضغط الزيت

  1. Oil pressure sensor depends on the resistance change
  2. pressure oil sensor depends on current change
  3. Oil pressure sensor depends on voltage change

One of the most famous fault of the oil pressure sensor is the difference in its readings. and the fluctuation of the readings significantly and Therefore, it must re-calibrated periodically to ensure the correctness of the resulting readings.

And one of the most common malfunctions in oil pressure sensors. It is the blockage of the sensor itself due to the entry of some impurities inside the sensor

Electrical faults of cooling water generators sensor

The cooling water sensor is responsible for detecting the low water level in the generator water tank (radiator). The low level of the cooling water leads to a high temperature of the generator and stops it.

The cooling water sensor works with the float system. Which is based on the electrical point contact system. When the water level drops, the two ends of the sensor contacted , which leads to a signal to the control panel stating that the water level is low and leads to the generator stopping.

Water sensor malfunctions are the damage to the internal circuit of the two terminals or the float inside the sensor.

Damage to the wires connected to the sensor also occurs due to the high heat generated by the generator. in some cases where the wires connected to the sensor not well insulated.

electrical faults of generators control screen

Most electrical faults are due to a malfunction in the generator control screen.

electrical fault of Generator control screen

This is because the signal does not come out most of the time. Therefore, you must first check the electrical points on the screen, and these points divided into four sections:

Binary input points

These points responsible for the signal of the sensors.

it depend on the signal system using the signal points between the two ends of the sensor and they use in electrical protection work.

Analog input points

These points responsible for entering the sensor signal in the form of digital values ​​that appear on the control screen. It is also use for protection by following the values ​​of the sensor.

Binary points output

this points responsible for sending the signal from the control panel to the generator. and these signals are the signal send to the solenoid and the initiator, which controls the generator start and stop

Analog output points

These points are responsible for sending numerical values ​to monitors or other devices connected to the generator.

Also, these points are not common in many control screens.


There are many electrical faults in generators we  didn’t mentioned in this article.

But the most important 7 electrical malfunctions of generators we mentioned here .

which are very common. And you should consult and communicate with us if you encounter other malfunctions.

Read More:

Voltage failure in generators