Generator and Device For Sequencing Loads On

[Mark]

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

 

[Phil Scott]

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

You would wire a time delay relay into the AC compressor
control circuit... refrigeration and AC wholesale supply
houses sell such time delay relays along with wiring
instructions...in you case you will need to add a magnetic
contactor to the compressor control circuit for that to work.

you need a diagram for the many options,


Phil Scott