Quote:
Originally Posted by Chance
The reason I asked is that some or many air conditioners are rated under severe conditions expected in the desert, and at least for Coleman A/Cs, the severe cooling is combined with low voltage of 103.5 Volts. That happens to be 90% of 115 Volts, their standard rating.
No doubt lower voltage will cause higher current, but so do other conditions. The question for me is whether high temperature will occur often enough and at an elevated level that will shorten the A/Cs life significantly?
I’ve never used one, and also never replaced an A/C, so I’m not sure if the added “insurance” premium is worth it.
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My Progressive Industries EMS shuts down at 103 volts. It will come back on if the voltage rises to 104 for 40 seconds.
As for a motor's temperature, it is power is equal to amperage squared times resistance. In electric motors the resistance is not fixed but varies with temperature because copper wire more resistant the hotter it gets until it melts. The compressor is usually oil cooled, sealed unit with an internal heat cutoff at about 150 degrees. So the 1500 watt A/C is using 12.5 amps@ 120 volts and has a resistance 9.6 ohms. Drop the voltage to 104 volts and the amperage draw is 14.4 amps or 33% more heat. Now the resistance increase and the compressor struggles to maintain pressure causing more heat. What happens next depends on the outside temperature and your A/Cs design parameters.
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