The company I work for has a server room with a Coleman 15Kw backup generator. The window AC unit was replaced with a higher BTU unit (18,000 => 24,000) resulting in approx. a 3 amp (230v) increase in power consumption. Well, this increase was just enough to prevent the generator from taking the load when the transfer switch switches from line to generator. If I do a load test with the AC off and wait for the generator to catch the UPS loads first and then turn on the AC (after waiting a few seconds), the generator can then supply power for both the UPS's and AC without tripping the generator breaker.
My question, is there a device which would automatically delay power to an electrical outlet (in this case the AC unit's receptacle) once power is available again? Ideally this device would act as breaker and delay, thus replacing the breaker (probably no such device is likely) or be installed between the breaker and receptacle. This would then perform the same action as manually delaying the startup of the AC unit. The fact that the AC unit would have a delayed start when switching to generator and again when switching back to line, isn't necessarily a concern.
Another question I have concerns balancing legs and generator capacity. I took a clamp on amp meter and measured 41A on one and 32A on the other. The generator is rated at 103A (with natural gas). How far is too far for balancing the leg loads and how close to rated output can a generator be operated safely?
Thanks in advace, Mark