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Power-User

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Power Consumed and Produced

12/09/2010 9:47 AM

On the nameplate of AHU there stand for its fan's motor :

shaft power 11 kW

power 15 kW

el.power consumption 14.447 kW

How can the power consumed be less than that produced ?

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Power-User

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#1

Re: power consumed and produced

12/09/2010 10:49 AM

If you are referring to the shaft power (11 Kw) it is called break horse power (BHP), in other words "BHP + Losses in motor" equals the electrical power measured by the electrical meters.

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Guru
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#3
In reply to #1

Re: power consumed and produced

12/09/2010 11:00 AM

Brake HP, not Break. But yes.

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Guru

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#4
In reply to #3

Re: power consumed and produced

12/09/2010 3:14 PM

Give him a break. He got all the letters.

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#5
In reply to #4

Re: power consumed and produced

12/09/2010 6:19 PM

Brake break given...

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#2

Re: power consumed and produced

12/09/2010 10:57 AM

Losses. 11kW / 14.447 kW = about 24% in total losses. Probably 10-15% of that is in the motor conversion (copper losses, iron losses, windage, friction, stray) and the rest is probably losses in the mechancial power transmission devices, i.e. belts, journals bearings etc.

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Guru

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#6

Re: Power Consumed and Produced

12/11/2010 4:48 PM

The mechanical power coming out of the shaft is 11 kW, that is the power produced. The electrical power put in is 15 kW, that is the power consumed. The power consumed is greater than that produced, please drink less vodka before calculating!!

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Guru

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#7
In reply to #6

Re: Power Consumed and Produced

12/12/2010 4:20 AM

Purist .....

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Guru

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#8
In reply to #7

Re: Power Consumed and Produced

12/12/2010 9:50 AM

Yes, but if Yuri calculated right, maybe he would not have asked the question! We would not be "blasting every tree in sight with a chain-gun trying to hit the Predator". Maybe Yuri will turn off his invisibility gismo and let us know if he understands better.......

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Guru

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#9
In reply to #8

Re: Power Consumed and Produced

12/12/2010 9:24 PM

I think your post straighted out the confusion perfectly. No over-unity was harmed by asking about what 'made no sense to him', so hopefully he will be back.

'chain guns'? Predator? I hate it when I miss the fun stuff!

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Anonymous Poster #1
#10

Re: Power Consumed and Produced

02/16/2023 7:08 AM
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#11

Re: Power Consumed and Produced

02/16/2023 7:11 AM

An <...AHU...> does not produce power.

<...el.power consumption 14.447 kW...> is probably sufficient to produce <...shaft power 11 kW...>.

A <...15 kW...>-rated motor is probably the nearest oversize for the application.

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