GM CS 144 alternator repair and replacement

Jump to: navigation, search
(added comments on diode damage)
Line 68: Line 68:
  
 
'''What is the most common cause of alternator electrical failure?'''
 
'''What is the most common cause of alternator electrical failure?'''
 +
Short term  (quick) damage:
 +
 +
* One relatively common cause of alternators is "ground lift" where a poor connection causes high levels of electrical "noise" in the system. This noise in the form of voltage pulses can exceed the breakdown voltage of the diodes and compromise reliability. A good ground from alternator to engine block to chassis/battery is paramount to a reliable electrical system.
 +
 +
* Another major cause is "load loss" where a poor connection loads and unloads the alternator on the plus side of the system. This is akin to disconnecting the battery while the engine is running. The loss of load on the alternator can damage the diodes due to over voltage.
 +
 +
Long term damage:
 
   
 
   
 
The component that has the highest failure rate on most alternators is the Bridge Rectifier. The Bridge Rectifier (aka rectifier) is the component that converts the Alternating Current (AC) that an alternator makes to Direct Current (DC) for use by the vehicle. Over time or under high demand situations the diodes in the bridge rectifier can become weak, they don't do as good a job as they did when they were new. You can tell your bridge rectifier is going bad when you first start a cold vehicle and it charges better at first compared to after it warms up. As the diodes in the bridge rectifier heat up they don't work as well. In high demand situations the more AC power the alternator makes, based on demand, the more power the rectifier has to convert to DC leading to a greater chance of diode failure.
 
The component that has the highest failure rate on most alternators is the Bridge Rectifier. The Bridge Rectifier (aka rectifier) is the component that converts the Alternating Current (AC) that an alternator makes to Direct Current (DC) for use by the vehicle. Over time or under high demand situations the diodes in the bridge rectifier can become weak, they don't do as good a job as they did when they were new. You can tell your bridge rectifier is going bad when you first start a cold vehicle and it charges better at first compared to after it warms up. As the diodes in the bridge rectifier heat up they don't work as well. In high demand situations the more AC power the alternator makes, based on demand, the more power the rectifier has to convert to DC leading to a greater chance of diode failure.

Revision as of 17:55, 12 February 2011

Personal tools
Namespaces
Variants
Actions
Navigation
Categories
Toolbox