Why isn't the generator generating electricity?

Generator core residual magnetism is fading or too weak

Newly installed generator sets, due to long-distance transportation vibration or prolonged placement of the generator, may experience the loss or weakening of the residual magnetism in the generator core. This results in the generator's residual magnet voltage disappearing or falling below the normal residual magnet voltage value, i.e., the residual magnet line voltage is less than 10V, and the residual magnet phase voltage is less than 6V. Since the stator and rotor cores of synchronous generators and AC excitation machines are typically made of 1-1.5mm thick silicon steel sheets, which are stacked and magnetized, vibration can easily cause the residual magnetism to disappear or weaken, directly leading to the inability to produce current during normal operation and resulting in no power generation.

2. Excitation circuit wiring error

During the overhaul of the generator set, an accidental reversal of the polarity of the excitation winding resulted in the generated magnetic field by the excitation winding current being opposite to the residual magnetic field direction, thereby canceling it out, causing the residual magnetism to disappear. Additionally, during the overhaul, failing to pay attention to the polarity when measuring the DC resistance of the excitation winding or testing the Automatic Voltage Regulator (AVR) while passing DC current through the excitation winding can also cause the iron core's residual magnetism to disappear. Such situations are due to operational errors at the factory and can be directly addressed by contacting the manufacturer for repair.

3. Excitation circuit is not conducting

Electrical contact issues within the excitation circuit of the generator set, or loose connections at each electrical component terminal, lead to wire breaks, causing a circuit interruption and the absence of excitation current in the generator's excitation winding.