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Old 07-21-2012, 11:20 AM   #1
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Generator AC unit


Hi

I have a 15 kw singel phase generator at home, the generator powers the house plus one 1,5 ton windows ac units and a 1,5 ton spilt unit.

The problem is when the generator is on the window ac is turned on 3 min after the gen has started after 3 min from the start of the window ac the siplit unit goes on and when it does that the generator stall and the voltage protections that is installed on the ac unit's turns of the ac unit's

is there any thing that can be done to solve this problem ?

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Old 07-21-2012, 11:37 AM   #2
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Generator AC unit


What brand generator and transfer switch?

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Old 07-21-2012, 11:54 AM   #3
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Its a perkins generator and the transfer switch is home made
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Old 07-21-2012, 12:16 PM   #4
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Quote:
Originally Posted by quanchai View Post
Its a perkins generator and the transfer switch is home made
nuff said
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Old 07-21-2012, 12:45 PM   #5
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Quote:
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Its a perkins generator and the transfer switch is home made
Im sorry, what?
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Old 07-21-2012, 02:26 PM   #6
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is there any thing that can be done to solve this problem ?
Hard start kit for some of the ACs; it's a $40 gamble.

So, how did you make the transfer switch?
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Old 07-21-2012, 06:00 PM   #7
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Magnetic relays it's made to transfer the power betwin 3 power sources, It does around 20 transfers a day has been working for 2 years now without a single problem

I can take a picture of it an show you ?
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Old 07-21-2012, 07:00 PM   #8
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That's not exactly homemade. I think what most are thinking is some hand welded giant switch you pull. Had me worried there.
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Old 07-21-2012, 07:22 PM   #9
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It could simply be that you are maxing out the power capabilities of the generator with other loads in the house when the second A/C is trying to start. A/C units and motors draw quite a bit of current for a short time when they are first starting.

Is this a new A/C install or has this configuration been running ok in the past?
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Old 07-22-2012, 09:31 AM   #10
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Magnetic relay
Assuming it costs less than $400 or so, I'm interested in the maker and part number for this relay that has been proven to work in this application.
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Old 07-22-2012, 01:28 PM   #11
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the house alone just need's 7 amps so i dont think its a problem for the generator
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Old 07-22-2012, 01:29 PM   #12
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the spilt unit is 6 years old but works fine
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Old 07-22-2012, 01:31 PM   #13
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it cost me 50 dollars to buy all the parts that i needed to build the ATS
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Old 07-22-2012, 01:34 PM   #14
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It's the surge/rated watts ratio for the gen (probably 1.6:1 or less) vs
the surge/rated watts for your loads (could be 10 to 1).

15kw @240 gives you 63A steady state capability.
The surge for my 2.5 ton central air is 4x or 5x the steady state amp value, probably going to 2x steady state within 0.1 second of startup and to 1x within one second.

Last edited by Yoyizit; 07-22-2012 at 01:40 PM.
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Old 07-22-2012, 01:41 PM   #15
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so is there any way to reduce the surge ?

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