[AMC-List] Compressors and Horse power

[David Crooks <david.crooks@xxxxxxxxxxxx>]

*** Warning!  Cranky Engineer!  ***

> Be careful of the HP ratings when you're comparing compressors.  
> Many companies still use "peak" HP.  I saw one the other day at 
> Home Depot that was rated for 7HP, but only drew 11 amps.  That 
> has to be peak HP.  A true HP rating for that motor would be around 
> 2.5 or 3.  Rule of thumb is 4-5 amps per 1 HP.  

I don't know what kind of scale some tool companies use for rating 
Horse power, but it's probably the same one that causes people to 
remember their old Ford had a 400 HP 289!  Sorry if I rant a bit, 
but it's a pet peeve of mine!

1HP = 746 watts, which means a 100% efficient motor can only 
get 2.3 HP out of a 15 amp 115 volt, circuit.  Ever felt a motor 
that was stone cold after running a while?  No?  I guess none are 
100% efficient then are they!

About the most you'll get from a 115 volt, 15 amp circuit is 2 HP,
and that's being pretty generous.  Their 11 amp motor, at 230 volts
is going to be 3 HP tops, just as you thought.

Grumble Grumble!

Dave

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