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Running Watts

Running Watts

Running Watts

(OP)
I would like to estimate the energy consumption of a dishwasher motor. If I assume it is a 1/4 horsepower motor, that implies it's about 190 watts, and draws about 1.6 amps. But it would not be running at full load all the time and must be de-rated so it will last for many years. What would be the typical running watts in this this kind of application?
Thanks for the help.

Later, John
 

RE: Running Watts

No way to know for absolute sure without measuring it. But why is that level of accuracy so important? If looking at protection for the circuit, you must always use the FLA not watts. If looking at maximum energy consumption, use the rating of the motor and you will not be under estimating. EXACT energy consumption is going to be varying with load and since an appliance is a time-limited consumer, any slight variations during that limited operating time become almost meaningless.


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RE: Running Watts

"...and must be de-rated so it will last for many years."

Oh man, I must find out what brand this is. All the others use the reverse logic: run it slightly past its rating and guarantee a steady business selling parts... neutral
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Running Watts

Huh, as many times as I have seen that Kill-A-Watt unit espoused in forums, I should buy stock in that company. Seems to be ubiquitous. Those sell for around $35US on average, great deal. These poor souls are trying to sell theirs for $120US...
http://www.bluelineinnovations.com/default.asp?mn=1.274.285.388
 


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln  
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies  

RE: Running Watts

I have a KaW.  Truly an awesome product.  I use it all the time for 120V loads. Really well done.

  It monitors about every parameter you'd ever want. You can even put in your price of electricity and it displays cost of operation.

The wall version is a lot cheaper but less robust and less convenient for studies.  As crawling around on hands and knees to cycle thru the various displays is NOT convenient.

But back to the dishwasher. A dishwasher's motor would be run right at its rating because it's easy to measure and the load never changes.  This is not like a washing machine. A dishwasher also runs continuously for a long periods.

 

Keith Cress
kcress - http://www.flaminsystems.com

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