What is Under-voltage?
Under-voltage refers to the situation where the output voltage of a generator remains below its rated value (e.g., 220V or 380V), which may prevent equipment from starting or cause damage. This issue needs to be addressed promptly to avoid affecting the power supply system.
Common Causes and Corresponding Solutions:
- Insufficient Prime Mover Speed
- Cause: The diesel or gasoline engine speed is below the rated value (e.g., 1500/1800 RPM). Voltage is proportional to speed, so a low speed results in insufficient power generation.
- Solution: Check the fuel system, throttle control, or drive belt for issues, and adjust the governor to the standard speed.
- Excitation System Failure
- Cause: Abnormalities in the excitation circuit (DC circuit generating the magnetic field), such as short circuits in the excitation winding, worn carbon brushes, or a faulty excitation machine, leading to insufficient magnetic field strength.
- Solution: Clean or replace the carbon brushes, use a multimeter to check the resistance of the excitation winding, repair any open/short circuits, or replace the excitation machine if necessary.
- Overload or Short Circuit of Load
- Cause: The connected equipment exceeds the generator’s capacity, or there is a short circuit in the circuit, causing the voltage to drop.
- Solution: Disconnect part of the load, prioritizing the shutdown of high-power equipment, and check the insulation of the wiring to eliminate short circuits.
- Voltage Regulator Failure
- Cause: Aging components or misconfigured settings in the regulator that prevent it from stabilizing the output voltage.
- Solution: Recalibrate the regulator parameters or replace components such as the AVR (Automatic Voltage Regulator) module.
- Winding or Internal Connection Failure
- Cause: Moisture in the stator winding or aging insulation causing partial short circuits, or loose internal connections.
- Solution: Have a professional technician check the winding resistance, dry or rewind the coil, and tighten any loose connections.
- Line Loss or Poor Contact
- Cause: Long output lines, small wire diameter, or oxidized connections causing excessive voltage drop.
- Solution: Shorten the power supply distance, replace the cable with a thicker one, and polish and tighten the terminal connections to reduce contact resistance.
Daily Maintenance and Preventive Measures:
- Regular Monitoring: Use a voltmeter to monitor the output voltage and troubleshoot any fluctuations promptly.
- Environmental Management: Keep the generator dry and well-ventilated to prevent moisture buildup or poor heat dissipation in the windings.
- Load Planning: Avoid starting multiple high-power devices simultaneously, and upgrade the generator capacity if necessary.