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Author Topic:   Stock Delco Alternator Output
posted May 13, 2002 08:53 AM
What kind of amps does a stock GM alternator put out?

Anyone ever put a switch on the alternator output wire? We were thinking that if we switched off the alternator if would cut the resistance and help keep the belt on. I also found out the hard way that I need a fuse on it.

posted May 13, 2002 10:02 AM
I think you can accomplish the same thing by putting the switch in series with the alternator field, and avoid having the full amp output going thru the switch. When you kill the field by throwing the switch, output drops to zero.

posted May 13, 2002 01:53 PM
They range from 35 to 100 likely it would be a 60 amp. They really don't have much drag as they only put out as many amps as you need to run the car which would be less than 10. They change at high rates if your battery is dead or weak or right after starting. The hp usage at 60 amps calculates to just under 1 hp, so at 10 amps it is 1/6th of a horsepower. To keep belts on you may try a larger pulley and make sure the pulleys are aligned and the brackets not deflecting when the throttle is applied. I also had a problem with mud getting in that area and kicking the belts off, so I put a piece of aluminum from the rad to the x-member under the engine.

posted May 13, 2002 02:02 PM
Another guy and I were just kind of kickin the idea around, but that isn't enough drag to cause the belt to jump or justify the switch. This is an all new set up, but I was throwin belts like a mad man last year. I have switched to and under drive crank and over sized alternator pulley. Hopefully that will slow everbody down enough to make thm happy.

Will a 30 amp fuse be high enough to protect the system but not blow when the alternator is taxed (e.i. - after cranking the motor a bunch)?

One more thing, what is the amp draw on typical systems?

Electric Fans?
HEI Ignition?

[This message has been edited by WesternAuto17 (edited May 13, 2002).]

posted May 13, 2002 03:52 PM
I put a 60 amp fuse (on my mopar) for the main power wire from the alternator and it has not blown yet. The fuse and fuse holder I got from my local dodge dealer. It looks like the regular GM push-in fuse but is larger. If you are interested I can get the part numbers. GM or a jobber may sell the same thing.

posted May 14, 2002 09:33 AM
I'm very interested in the part number. I've never had a problem w/o a fuse, but a friend pinched the wire and cooked all the wiring in the car. Doh! I don't want to replace it all again.

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