Motor Specification Query

Tis is the rating plate on a dewalt saw. Can anyone suggest the meaning of P1 and P2?

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The only interpretation I could guess at is electrical power in =P1 and mechanical work out is =P2 but this would mean 3.4 hp input and about 700 watts waste heat.

It is a 3 phase induction motor.

I want to see what rating inverter I will need to use to run the saw.

TIA

Bob

Reply to
Bob Minchin
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Consumption wired as Star or Delta ?

AWEM

Reply to
Andrew Mawson

Hi Andrew,

I'd have expected star and Delta powers to be the same. the two current ratings are in the correct ratio for star & delta I also note that the product of the voltage & current in either star or delta is roughly the P2 figure which suggests this is the VA rating which should be greater than the true power consumed.

Hmm!

Confused of Romsey

Bob

Reply to
Bob Minchin

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Star and delta power will vary if the voltage stays the same. This is why big motors use star/delta starters

AWEM

Reply to
Andrew Mawson

True but I don't think this is the meaning in this instance as the ratio of the powers quoted is not the same as the ratio of the currents quoted.

I have just seen elsewhere a saw of the same brand with Power in and Power out quoted in similar proportions.

If i end up buying the thing I'll just have to make some measurement to satisfy my curiosity!

Bob

Reply to
Bob Minchin

My guess is that you're right. Rating plates for stuff like welding sets uses that convention,of a suffix (1) for input and (2) for output.

OK, so it's inefficient

Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Reply to
Tim Leech

Bob,

I think you're missing out the famous square root of 3 in your calculations. Taking this into account, the apparent power will be about 2.8 kVA in either case. I think it's possible that the lower power figure is a continuous rating, and the higher figure an intermittent rating.

Best wishes,

Chris

Reply to
Christopher Tidy

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