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Compressor Amp Draw #34522
02/14/04 01:24 PM
02/14/04 01:24 PM
G
golf junkie  Offline OP
Member
Joined: Apr 2001
Posts: 507
York, NE
Does anyone have a chart for rule of thumb amperage draws on HVAC and refrigeration compressor based on tonnage??

For instance how many amps does a 208v, 3ph, 5 ton compressor draw?

GJ

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Re: Compressor Amp Draw #34523
02/14/04 02:05 PM
02/14/04 02:05 PM
J
Jps1006  Offline
Member
Joined: Jan 2004
Posts: 615
Northern IL
Obviously you are looking for a way to estimate site unseen for ball-parking a bid or having some idea for sizing something. Just thought I'd say that before you get "You really should size it off the nameplate rating".

I don't know off hand for your example, but I've found for single phase 240 volt, about 10 amps per ton. That's breaker size. 5 ton 50 amp breaker, etc.

Re: Compressor Amp Draw #34524
02/14/04 03:02 PM
02/14/04 03:02 PM
G
golf junkie  Offline OP
Member
Joined: Apr 2001
Posts: 507
York, NE
Jps,
You are correct, I'm looking for a ballpark estimate. The final circuit sizing will be done from the nameplate info.

We are running to more and more requests where people are trying to save on the engineering. Tough to bid when it's all rather undefined.

I found a conversion that says 1 ton=4.71HP. Going back to my example then I calculate;

5 ton = 5 x 4.71 = 23.55hp

The amp draw for that doesn't come close to matching carrier's data for a 5 ton RTU. Carrier says that a 5 ton RTU 208v, 3ph, has a FLA of 32A.

????????????????

Re: Compressor Amp Draw #34525
02/14/04 04:57 PM
02/14/04 04:57 PM
W
wolfdog  Offline
Member
Joined: Oct 2001
Posts: 135
Dallas,TX
12,000 BTU (1 ton) = 4.7161 horsepower hour as a raw calcultion with formulas.

It does not translate into hp/ton on small equipment.


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