I just put on a new 140A powermaster alternator. It makes a lot more noise than the stock 105A did. Its sort of like a clicking/whirring sound (see vid below), almost like a blower. Is it normal for these? I know theyre different than factory alternators.

http://www.youtube.com/watch?v=kQIgF...el_video_title

 

I've had several powermaster alternators none of them sounded like that. Looks like you need to send it back. I would call or email their tech support first and show them the video so they can hear it too. Powermaster from my experience has very good tech support and customer service. It sounds like a bad bearing or something inside is rubbing. Did you have to take the alternator apart and clock it to a different position? If you didn't get it seated back together correctly that can happen.

 

Actually sounds like its coming from the field coils or something, but it could be the rotor hitting the inside of the stator, too.

Only thing I did was to change the pulley.

Although this is a frequency/DC regulated CS130. I know its normal for them to make a little hum, but that seems like a bit much.

 

They will make a little bit more noise since they're putting out more amperage, but nothing like what you're hearing.

Be really careful when you change the pulley too. On a CS130 style alternator the pulley should be facing towards you as if in the installed position when you take it off and put it on. If you flip it up so the bearings are facing down against a table top, it's pretty easy to knock everything out of alignment and the brushes off the slip rings, especially when using an impact gun.

 

I used a strapwrench to hold the pully still when removing the original and installing mine, so there wasnt any excessive loads put on the alternator. I just sat it down on the bench and swapped them.

Oddly enough, the noise is gone now and sounds like a normal alternator. I think the noise was in the regulator as it was silent running without the 4-pin connector plugged in when it was doing what it did in the vid. Theres no interference in the radio (AM or FM) from the alt., so it doesnt imediately indicate a bad diode or something. Could it be due to the brushes not being seated and making proper contact with the slip rings? Seems possible if it was abused during shipping.

No word from PM yet.

 

VERY belated update, but I found out what the issue was. Powermaster uses locking patches on the housing screws, and the torque they used was not enough to fully seat them. I took the alternator off yesterday for something else and the housing halves were just sloppy loose. With it installed the belt tension made it impossible to tell. So, all the noise was the rotor and stator getting too close to each other. Tightened the bolts and that fixed it.