Alternator trouble shooting
Failure | Cause | Treatment |
Can not power | Alternator | Wiring mistake | Check and correct according to wiring diagram |
Severe defects such as broken line of rotor winding or excitation winding | Check relevant winding resistance by the universal meter, and if winding resistance is infinite, broken line should be connected. If winding resistance is zero, it should replace or process coil. |
Broken line of alternator stator winding and excitation winding | Check resistance by the universal meter, and if resistance is infinite, broken line should be connected. |
Rotating-rectifier module breakdown and short circuit | Check forward reverse resistance by the universal meter and when it shows zero, rotating-rectifier module changes. |
AVR | The output lead wire is not connected.
| Connect lead wire |
The fuse is damaged. | Change the fuse in the inner voltage regulator. |
Voltage regulator is damaged. | Change voltage regulator |
No load voltage is too low or too high | alternator | The rpm of alternator is too low or too high. | Adjust generator speed to rated speed |
Excitation winding is rare short. | The current of exciter’s excitation winding is large. Excitation winding is serious heat and big vibration. Excitation winding’s DC resistance is smaller than its normal value. It needs the return-to-factory service |
Rotating-rectifier module is at fault. | Open NDE-shield’s cover back plate sheet，disconnect F1 or F2 joint, check rotating-rectifier module by the universal meter. If forward reverse resistance does not accord with the requirement of the properties of the diode, it changes damaged rotating-rectifier module. |
AVR | Wiring mistake | Check whether wiring circuit is correct |
Erroneous measure voltage causes low output voltage or unadjustable. |
Voltage setting point is too low or too high. | Adjust voltage set potentiometer in clockwise or counterclockwise direction until voltage meets with requirement. |
Remote voltage setting point is too low or too high. | Adjust remote voltage setting potentiometer in clockwise or counterclockwise direction until voltage meets with requirement. |
Voltage regulator is damaged. | Change voltage regulator |
Failure | Cause | Treatment |
Voltage oscillation | Voltage regulator is damaged | Adjust STAB knob, and if it can not make voltage stable, it should change voltage regulator. |
Voltage is not adjustable | Voltage regulator is damaged. | Change voltage regulator |
Alternator overheating | Alternator overload | Minimizes load to not exceeding nameplate rated value. |
The power factor of the inductive load is low. | Adjust load to make exciting current not exceeding rated value |
The rpm of alternator is too low. | Adjust alternator speed to rated value |
Alternator vent is blocked. | exclude blockage |
Bearings overheating | Bearing is excessive worn out. | Change new bearing |
Lubricating grease of brand is wrong, or grease is the impurity, or grease is overfilled. | Bear is cleaned by kerosene, and change grease according to lubricating grease of brand, and the grease quantity should be 1/2—1/3 of non-bearing room capacity. |
The connection with prime mover is not good. | Correction and alignment |
Big vibration | The connection with prime mover is not good. | Correction and alignment |
Rotor dynamic balancing is not good. | Dynamic balancing emendation |
Prime mover vibration | Check prime mover and adjust it |
How does alternator do separated excitation? What is separated excitation used for?
How to do separated excitation? Connect exciter’s stator wire ( mark “F1”“F2”) with 12V DC power （12V DC power supply）,“F1”connects the anode of DC power supply, “F2”connects the cathode of DC power supply. After insulation treatment, generator set starts and you observe generator voltage.
What is separated excitation used for: before separated excitation, check whether circuit in the generator box body (include AVR wiring) is connected properly. Through separated excitation, judge the failure that is alternator body internal failure (stator, rotor, exciter stator, exciter rotor, rotating rectifier module) or generator box internal wiring failure（circuit wiring, AVR）.
For concrete trouble-shootings, please see PPT of alternator installation and trouble-shootings
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