Delaying a distribution panel load
Delaying a distribution panel load
(OP)
Hi,
I need some advice. I am an electrical engineer in charge of a telecom facility electric distribution system. We have a generator that cannot manage the start up load of the facility.
It was suggested that a time delay be used to bring the load online 3 minutes after the generator has started to run. However, I have problem with mechanism the electrical contractor is proposing. The contractor is proposing to use a normally open 320Amp contactor and a time delay relay. My concern has to do with the use of a normally open contactor. I fear that if the normally open contact fails it will disconnect power from the distribution panel feeding the load with power. Quite frankly I would prefer a normally closed contactor. So that if the contactor failed it would fail close thus still keeping power on the panel.
Does anyone know of any good way that the distribution panel maybe delayed using a normally closed contactor or any other feasible solution.
I need some advice. I am an electrical engineer in charge of a telecom facility electric distribution system. We have a generator that cannot manage the start up load of the facility.
It was suggested that a time delay be used to bring the load online 3 minutes after the generator has started to run. However, I have problem with mechanism the electrical contractor is proposing. The contractor is proposing to use a normally open 320Amp contactor and a time delay relay. My concern has to do with the use of a normally open contactor. I fear that if the normally open contact fails it will disconnect power from the distribution panel feeding the load with power. Quite frankly I would prefer a normally closed contactor. So that if the contactor failed it would fail close thus still keeping power on the panel.
Does anyone know of any good way that the distribution panel maybe delayed using a normally closed contactor or any other feasible solution.





RE: Delaying a distribution panel load
RE: Delaying a distribution panel load
But all is not lost. Consider a breaker with a motor operator.Add a shunt trip to trip the breaker before the generator starts and then reclose the breaker with the motor operator.
I don't have numbers but I would think that the standard contactor may have a slight edge on the breaker for reliability if the breaker is being switched often.
My first solutio may be to take David's suggestion;This approach may be cheaper and more dependable.
Bill
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"Why not the best?"
Jimmy Carter
RE: Delaying a distribution panel load
Ideally a bigger generator would be the best option.However, that option is not available. The sequencing of the load is actually what we are doing.
What is ampacity of these latching contactors
RE: Delaying a distribution panel load
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