jcmoretti

I just installed a CS130 alternator in my car. I've had it for a year or so just sitting in a box. It is making a humming sound when the car is running. It is silent when the car is off. I have the Bat post tied back to the battery. I have the 'L' post tied to 12v with the ignition via the electric choke, which feeds off the ignition for the HEI.


The sound is only there when I have 12v to 'L'. The alternator is indeed charging as I read 14 volts when 'L' is connected and 12 volts when it isn't. I get the same noise when I send 12v directly from the battery (with the car running). Am I doing something wrong? Thanks in advance.

stellar

Frank Zappa wrote a song about that "Dynamo hum."

stellar

I'm not sure what is making your Diana moe humm. You must have a quiet car to hear it. Are you hearing it under the hood or through the radio? The cs130 had very close internal tolerances. The rear bearing was a problem. It may be rubbing if the rear bearing tolerance ring is bad. They can make a sound when charging, but usually it is described as a whine and not a hum. Can you be more specific about the noise?

joe_padavano

I can't say that I'm following your wiring description. The "L" terminal on the alternator is for "Light" and should be connected to the brown wire that goes to the GEN idiot light. The "S" terminal on the alternator is for "Sense" and should be connected to the threaded stud on the horn relay. Also, be sure to run a dedicated ground strap from the rear case of the alternator to engine ground. The CS130 is very sensitive to this and the regulator can be damaged without a good ground. There is a TSB out on this.