Causes and solutions for low generator voltage output

Common causes

1. Insufficient engine speed

Reason: Excessive load, carbon deposits on the throttle or exhaust pipe may cause the engine speed to be too low. When the engine speed is too low, the rotor rotates slower, and the speed of cutting the magnetic lines of force will also decrease, resulting in a decrease in the induced electromotive force, and ultimately a decrease in the voltage output by the generator.

Solution: Reduce the load and clean the carbon deposits.

2. Excitation system failure

Reason: The excitation system is the key to the normal operation of the generator. If the resistance of the excitation circuit is too large, the excitation winding is connected incorrectly, the excitation machine brush is not in the neutral position, or the spring pressure is too small, the generator output voltage will be reduced.

Solution: 
1. Reduce the resistance of the excitation circuit to increase the excitation current.

2. Correct the wiring of the excitation winding according to the circuit diagram.
3. Adjust the position of the excitation machine brush to ensure that it is on the neutral line, and check the spring pressure.

3. Damage to the rectifier diode

Reason: Some rectifier diodes are broken down or their performance is reduced, affecting the rectification effect of the generator.

Solution: Use a multimeter to check the rectifier diode. If damaged, replace it.

4. Winding failure

Cause: Short circuit, open circuit or grounding problem in the stator winding or excitation winding.

Solution: Use an insulation resistance tester to detect the insulation of the winding and repair or replace it if necessary.

5. Voltage regulator failure

Cause: The voltage regulator controls the output voltage of the generator. If a failure occurs, the voltage will be unstable or too low.
Solution: Check the working status of the voltage regulator and repair or replace it if necessary.

6. Poor brush contact

Cause: The contact area between the brush and the slip ring is small or the pressure is insufficient, resulting in poor contact.

Solution: Clean the brushes and slip rings, adjust the brush pressure or replace the brushes that are severely worn.

7. Excessive line resistance

Cause: Excessive resistance in the line, especially in long-distance transmission, will cause voltage drop.

Solution: Check the line, especially the parts that are easily damaged, and clean or replace the damaged cables.

Preventive measures

To prevent the problem of low generator output voltage, the following preventive measures can be taken:

1. Regular maintenance: Regularly check the status of various components of the generator, including brushes, rectifier diodes, windings and excitation systems.

2. Monitor the speed: Ensure that the prime mover always runs at the rated speed.

3. Use high-quality accessories: Select high-quality brushes, rectifier diodes and other accessories to extend the service life.

4. Professional training: Provide professional training for operators to ensure that they can properly operate and maintain the generator.