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Testing an alternators amp output

Discussion in 'The Garage' started by opfor2, Jan 1, 2007.

  1. opfor2

    opfor2 1/2 ton status

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    Hoe do I test an alternator to see how many amps it's producing? I have a supposed 200 amp alternator and I'ed like to see if it really can produce 200 amps.

    Thanks

    Dan..
     
  2. JEBSR

    JEBSR 1/2 ton status

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    You would have to use an ampmeter. Go to autozone, oreilly's, etc. , they have the capability of testing volts and amps.
     
  3. RockinChevy

    RockinChevy 1/2 ton status GMOTM Winner

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    for FREE!!!! :D
     
  4. beater_k20

    beater_k20 Banned

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    you want to see if it will really make 200 amps? at the point that it does make 200 amps, i predict a meltdown. so long as it runs everything you need it to run, leave it alone.
     
  5. randy88k5

    randy88k5 1/2 ton status

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    All the bench testers I have seen turn the alternator at a slower speed, so the current output is roughly about 15 amps IIRC. They just test to see if it is within a certain range, they dont test the max output.
     
  6. JEBSR

    JEBSR 1/2 ton status

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    Bench tester is for testing just the alternator, The tester they have for amp testing is a portable that test the entire system on the vehicle. It will tell you pretty close to what the potential of the alternator is.
     
  7. diesel4me

    diesel4me 1 ton status Premium Member

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    Full power??..

    You'd have to have it in a vehicle,with all lights on,(on high beams),all acessories on,and a carbon pile rheostat hooked across both battery terminals to create a "full load" situation,to see what the maximum output is..

    Of course you'll need an ampmeter, installed betwen the output wire of the alternator ,and the post it was bolted to,to read the output..

    You have to adjust the carbon pile rheostat while its running to load the system down enough to get an accurate reading..few if any places probably have a carbon pile rheostat,or even know what one is anymore--maybe a starter/alternator shop may still have one--they might have newer test benches that can read "full output" now..most GM alternators only reach about 80-90% of their rated output when installed in a vehicle,I guess its a safety factor, so it wont burn itself up...:crazy:
     

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