What's them idle current from the alternator?

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Top of pagePrevious messageNext messageBottom of pageLink to this message   By Dean Brown (Deanbrown3d) on Monday, October 15, 2001 - 04:45 pm: Edit

I want to get me an inverter for 110, you know the type that can get your well pump working when WWIII starts and the power's down. What's the output current (or power) from a disco alternator when idling?

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Dean Brown (Deanbrown3d) on Monday, October 15, 2001 - 04:51 pm: Edit

read 'the' rather than 'them' ooops

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Discosaurus (Discosaurus) on Monday, October 15, 2001 - 05:01 pm: Edit

...my educated guess is somewhere around 30-40A at idle for a 100A OEM LR juicer.

That's one of the tricks some aftermarket (...including my aftermarket 160A PPW) use to get idle output up - they run bigger pullies to spin them faster.

keith
discosaurus

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Tate on Monday, October 15, 2001 - 05:11 pm: Edit

I don't know the details of how alternators work, but the logic on the bigger pulley seems backwards. With a given belt speed, a larger pulley will spin more slowly. A smaller pulley would enable it to spin faster than normal. However, the force required to turn the pulley would be larger. However, if they rework the alternator to provide more power per revolution, the larger pulley would provide a larger lever arm to deal with the increased load, but spin more slowly. Perhaps this is the setup of the PPW alternator. Again, I'm just theorizing--this is interesting.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Dean Brown (Deanbrown3d) on Monday, October 15, 2001 - 05:16 pm: Edit

Hmm, not bad. I guess the battery can manage loads more for stuff like running a house's water pump. I just want to know roughly how much my $30K generator can produce continuously when idling!

I bought (and returned) a generator this weekend - the Generac XL 4000 - supposedly whisper quiet. Supposedly LOL. Well, when I turned it on, it was like a chain saw at full blast - how the fuck could they ever get away with that! 'Ultra quiet' MY ASS!

Sorry, just letting off steam. And BTW even though Home Depose say they won't take back a generator, you can use this story to get a full refund

Dean

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Dean Brown (Deanbrown3d) on Monday, October 15, 2001 - 05:17 pm: Edit

Tate,

I think Keith meant the driving pulley is bigger.

Dean

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Tate on Monday, October 15, 2001 - 05:58 pm: Edit

Dean, I thought he was talking about the pulley on the front of the alternator that is spun by the serpentine belt. Aren't we talking about the same thing?

From the premier power welder's site http://www.premierpowerwelder.com/about/aboutppw.html :
"Can I use my own pulley?
No. Our pulley is smaller to spin our alternator faster so that it will put out more amps at lower R.P.M.S. and function as a tool better. When putting on or taking off a pulley, always use an impact wrench (turn air pressure to 90 lbs.)"

Keith, if the pullies are different sizes, wouldn't this change the frequency of the pulse needed by the tach? Maybe this needs to go to a different thread....

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Discosaurus (Discosaurus) on Tuesday, October 16, 2001 - 12:28 pm: Edit

...sorry, I really DID mean smaller :)

Smaller drive pully on the alternater - faster rotation of the alternator - more goo at idle speed.

Yes, the tach reads about 150 RPM high at idle, same percentage as you go up. I've been told there is an adjustment pot on the circuit board you can diddle while watching a dwell meter or OBD scanner to set the tach right on. I just ignore the error.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle on Tuesday, October 16, 2001 - 12:50 pm: Edit

Bigger on race cars Keith , thats probably what you were thinking....


Kyle


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