spark288

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spark 288

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Here it is, I am trying to calculate a load for A/C - Heat combo units. They are being installed in a motel. Here are the facts; I have an existing 200 amp 3 phase disconnect that is supplying a chiller and the chiller will be disconnected. I am installing 58 AC/Heat combo units the FLA is 14.4 amps per unit.
I am looking for the calculation that I can use to tell me if I have enough power. THANK YOU
 
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spark2881

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I was having trouble loging back on so i had to create a new account.

THE VOLTAGE OF THE A/C UNITS IS 22OV SORRY I DIDNT STATE THAT
 
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spark2881

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spark2881

spark2881

I have had a few different answers, But does a demand factor get put into the equation since it is an appliance? Also the service is three phase does that formula get devided by 1.73?? These units are the ones that go through the wall under the window and are pluged in.
 
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iwire

iwire

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OK first off the units are not '220', if your doing calculations you need to use the correct numbers.

I will assume the service is 208Y/120.

To figure the loading of single phase equipment supplied from a 3 phase supply you have to forget amps and think watts.

Base on the little info here is what I get forgetting about power factor etc.

I am installing 58 AC/Heat combo units the FLA is 14.4 amps per unit
Click to expand...

14.4 amps x 208 volts = 2995 watts

2995 watts x 54 units = 161,730 watts or 161 KW of load.


Your 200 amp 208 volt 3 phase disconnect if maxed out can supply just under 72 KW.

208V x 200A x 1.73 = 71,968 watts or about 72 KW

In summery

161 KW of load

72 KW of supply


I think you have a problem.
 
Besoeker

Besoeker

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LarryFine said:
Unless I'm missing something, you need to figure 100% loading. I get 835.2a. (58 x 14.4).
Click to expand...
Wouldn't the aircon units be single phase?
In which case you'd get just about 14 per phase (assuming the single phase is phase to neutral voltage*) or 42 total.
It's still some way short of the 58 units of course, and it takes no account of any other connected load.
*If the single phase is derived from line to line voltage, the feeder is a long way short of meeting kVA loading.
 
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