# Watts and H.P.?



## speedre9 (Dec 5, 2013)

Been looking at spindles on E-bay. Many of them from Hon Kong and China but are rated in either watts or Kilowatts. Some are rated  200 w. and some are 1.5 kw. how do I know what the h.p. equivalents are.?


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## awander (Dec 5, 2013)

1KW is about 1.34hp


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## smallfly (Dec 5, 2013)

speedre9 said:


> Been looking at spindles on E-bay. Many of them from Hon Kong and China but are rated in either watts or Kilowatts. Some are rated  200 w. and some are 1.5 kw. how do I know what the h.p. equivalents are.?[/QUOte-------this link will answer your ques.http://www.rapidtables.com/convert/power/watt-to-hp.htm----enjoy--re  steve in  mt.
> 
> - - - Updated - - -
> 
> ...


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## Tony Wells (Dec 5, 2013)

I just use Google when I want to convert something I can't do in my head. Simply type in "convert 1.5kw to hp" and it will do it for you. Works for all sorts of conversions. It's a good calculator.


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## astjp2 (Dec 5, 2013)

smallfly said:


> speedre9 said:
> 
> 
> > Been looking at spindles on E-bay. Many of them from Hon Kong and China but are rated in either watts or Kilowatts. Some are rated  200 w. and some are 1.5 kw. how do I know what the h.p. equivalents are.?[/QUOte-------this link will answer your ques.http://www.rapidtables.com/convert/power/watt-to-hp.htm----enjoy--re  steve in  mt.
> ...


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## Tony Wells (Dec 5, 2013)

http://lmgtfy.com/?q=convert+1.5kw+to+hp


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## FanMan (Dec 5, 2013)

As others have posted above, 746W = 1HP.  _However_, while HP almost refers to the _output_ of the motor (assuming the manufacturer is being honest), the wattage can refer to either the output or the electrical power consumed by the motor... which will always be more than the output.

However, watts are also voltage times amps... so if, for example a 120V motor draws 10 amps (1200W) and they're saying 1.2kW, you can be sure that's the input and not the output power.


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## Ray C (Dec 5, 2013)

What everyone says is true and I'll add one more thing.  Sometimes you'll see ratings in Watts and sometimes it's expressed as kVxA.  Watts will always just be expressed as the nominal operating Voltage times the Amperage where as kVxA will often take into consideration the power factor which is usually estimated to be 0.8.  This means there is (in a typical inductive load like a motor) a 20% difference in the lag of peak voltage and peak current.  You'll notice that in almost all cases kVxA is 80% the value of the rated Watts.  That 20% is pure waste.  The Watts tell you how much your electric meter spins and kVxA is telling you how much work is actually being done.

Ray


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## FanMan (Dec 5, 2013)

Correction to my above post, "HP almost refers" should have been "HP _always_ refers".


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## speedre9 (Dec 6, 2013)

Thank you very much, I will be able to do the math now.


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## Maxx (Dec 6, 2013)

astjp2 said:


> *746 watts = 1 horsepower so a 1.5kw is just under 2 hp*, the 200 watt is about 1/4 hp.  Tim



New school math? :LOL:


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## David S (Dec 6, 2013)

Maxx said:


> New school math? :LOL:




Yes and I think you will find that Watts is actually V x A x power factor.  Just a minor correction.

David S


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## Ray C (Dec 6, 2013)

Mmmm, me thinks that Watts = VxA / power factor.




David S said:


> Yes and I think you will find that Watts is actually V x A x power factor.  Just a minor correction.
> 
> David S


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## DMS (Dec 6, 2013)

I think we  have probably answered the OPs question, but in the interest of completeness.

Apparent Power (S) = I*V
Power (P) = S*PowerFactor

so

PowerFactor = P/S

Apparent Power (S) will always be less than or equal to real power as power factor will always be a number between 0 and 1. The main effect that power factor is going to have on most folks wiring a machine is that at lower power factors you will require more current to produce the same amount of power (which effects the required wire size).

http://en.wikipedia.org/wiki/Electric_power

When I am converting from HP to watts and vice-versa, I usually just use 750W/HP. It's easier to do in your head, and it's close enough for most things.


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## astjp2 (Dec 7, 2013)

Maxx said:


> New school math? :LOL:



Nope, just keeping it REAL simple for those who struggle with numbers!:roflmao:


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