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purple hayes
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 Posted: 09/18/06 - 08:52 Post subject: question for the EE peeps
What's the max sustained HP you can get from an induction motor on 120V?
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j1miller
Puppy Love!
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Posted: 09/18/06 - 08:55 Post subject:
WTF? 
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RangerG
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Posted: 09/18/06 - 08:57 Post subject: Re: question for the EE peeps
| purple hayes wrote: | | What's the max sustained HP you can get from an induction motor on 120V? |
There are some missing factors in your question.
a)What is the rated HP of the motor?
b)What is the efficiency factor?
c)Single or Three Phase?
d)Cycles?
e)What are you using it for?
This should be found on a little data plate on the motor.
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gretriever
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Posted: 09/18/06 - 08:57 Post subject:
| j1miller wrote: | | WTF? |
I think he's got the aluminum foil hat on again. 
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cdnhollywood
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Posted: 09/18/06 - 08:57 Post subject: Re: question for the EE peeps
| purple hayes wrote: | | What's the max sustained HP you can get from an induction motor on 120V? |
Crossing boundaries here, unless you assume a perfect transfer of energy. Electrical power is voltage x current. You should be able to find the max current rating on the motor itself. This power is in watts, and 100kW = 138.1 hp.
This will be close for you. Other energy losses will be to heat and friction. If the motor is an expensive one, they may even specify the efficiency of the unit, which you could use to get a more accurate estimate.
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cdnhollywood
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Posted: 09/18/06 - 09:00 Post subject:
Oh, one thing I noticed is wrong. Max power does not occur at max efficiency. You'll be better off reading max HP off the plate on the motor.
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purple hayes
Frightened Inmate #2
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Posted: 09/18/06 - 09:03 Post subject:
Backstory :: Mrs. and I were watching an re-run of Everybody Loves Raymond and he's purchased a vacuum that he claims is 4HP. I told Mrs. PH that I thought 4HP wasn't possible with 120V household current.
True or False?
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RangerG
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Posted: 09/18/06 - 09:09 Post subject:
| purple hayes wrote: | Backstory :: Mrs. and I were watching an re-run of Everybody Loves Raymond and he's purchased a vacuum that he claims is 4HP. I told Mrs. PH that I thought 4HP wasn't possible with 120V household current.
True or False? |
Yes!
The Cr*ftsman shop vac in my workshop at home is a 6HP, and plugs right into a regular outlet.
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cdnhollywood
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Posted: 09/18/06 - 09:13 Post subject:
| purple hayes wrote: | Backstory :: Mrs. and I were watching an re-run of Everybody Loves Raymond and he's purchased a vacuum that he claims is 4HP. I told Mrs. PH that I thought 4HP wasn't possible with 120V household current.
True or False? |
It will all be based on the current you can get from your supply. 4HP is nearly 3000W, which, at 120V (which you don't get out your outlet), you'd need 25 amps. Only stoves, dryers and other large appliances get that much, and they're on their own breaker. All other circuits are either 10A or 15A.
It's possible, but not likely with "traditional" wiring.
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cdnhollywood
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Posted: 09/18/06 - 09:14 Post subject:
| RangerG wrote: | | purple hayes wrote: | Backstory :: Mrs. and I were watching an re-run of Everybody Loves Raymond and he's purchased a vacuum that he claims is 4HP. I told Mrs. PH that I thought 4HP wasn't possible with 120V household current.
True or False? |
Yes!
The Cr*ftsman shop vac in my workshop at home is a 6HP, and plugs right into a regular outlet. |
Hey, you're right! I guess it's time to pass my degrees back to the school....
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RangerG
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Posted: 09/18/06 - 09:36 Post subject:
| cdnhollywood wrote: | | Hey, you're right! |
Cuz I are a genius! Now the sooner new owners realize this, the sooner we can all be a big happy family again. 
| Quote: | | I guess it's time to pass my degrees back to the school.... |
It's all about application. When dealing with Vac units it's "Peak HP". Sort of a smoke and mirrors thing.. It may develop the Peak HP for a half second during starup and then drop down to a sustained HP that is quite a bit lower....and not apt to trip the breaker...or blow the fuse (for old farts like Andy and Gdawg). 
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JACKED UP
PRESIDENT
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Posted: 09/18/06 - 09:38 Post subject:
Well I wear a double E, on my feet you moron  , but I'm not sure about the HP.
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karlene
Canadian Bacon
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Posted: 09/18/06 - 09:39 Post subject:
| RangerG wrote: | | cdnhollywood wrote: | | Hey, you're right! |
Cuz I are a genius! Now the sooner new owners realize this, the sooner we can all be a big happy family again.
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Oh Wow, look it's a hot air balloon!! Nope, thats just Ranger's head  
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robp
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Posted: 09/18/06 - 09:42 Post subject: Re: question for the EE peeps
| RangerG wrote: | | purple hayes wrote: | | What's the max sustained HP you can get from an induction motor on 120V? |
There are some missing factors in your question.
a)What is the rated HP of the motor?
b)What is the efficiency factor?
c)Single or Three Phase?
d)Cycles?
e)What are you using it for?
This should be found on a little data plate on the motor. |
I'm not electrical expert but I don't think they make three phase 120V motors....
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purple hayes
Frightened Inmate #2
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Posted: 09/18/06 - 09:47 Post subject:
| RangerG wrote: | | ` It may develop the Peak HP for a half second during starup and then drop down to a sustained HP that is quite a bit lower |
That's why I asked about sustained HP in my initial post.
I know manufacturers want to put up big HP numbers, so they use the max HP instead of sustained.
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