Capacitor Bank/ Automatic Transfer Switch

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fjrivera

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Greetings,

I have encountered a company that has a capacitor bank installed in the load side of the automatic transfer switch. Capacitor bank is always on, indifferent if the service is provided from the electrical utility company or from the generator.

I always though that capacitor banks should be installed:
1) in the electrical utility company side of the automatic transfer switch or
2) in the load side of the automatic transfer switch and turned off when generator is turned on.

Can anyone explain why a capacitor bank should not be installed in the load side of an automatic transfer switch in order to avoid problem when generator is starting or entering in service?

Thanks.
 
fjrivera said:
Greetings,

I have encountered a company that has a capacitor bank installed in the load side of the automatic transfer switch. Capacitor bank is always on, indifferent if the service is provided from the electrical utility company or from the generator.

I always though that capacitor banks should be installed:
1) in the electrical utility company side of the automatic transfer switch or
2) in the load side of the automatic transfer switch and turned off when generator is turned on.

Can anyone explain why a capacitor bank should not be installed in the load side of an automatic transfer switch in order to avoid problem when generator is starting or entering in service?

Thanks.
Click to expand...

I would think that since capacitors store energy period, for a prorated time period that they would be more beneficial after the ATS than ahead of it to allow a gradual incline in the power supply versus a direct inrush from either the normal utility power or the generator source.
Carl
 
Krim said:
I would think that since capacitors store energy period, for a prorated time period that they would be more beneficial after the ATS than ahead of it to allow a gradual incline in the power supply versus a direct inrush from either the normal utility power or the generator source.
Carl
Click to expand...

That would be the case only if the instantaneous charge in the caps happened to match the polarity of first waveform from the power source. Besides, the caps are going to very quickly discharge into the load the instant the source is removed.

I think the cap bank is there for power factor correction. If it's there to make the power company happy, then I'd say it should be ahead on the ATS on the utility side. If the load is such that both the generator and the power company could benefit from it, then I'd say it's good where it is.

Disclaimer: I'm not an electrician. I'm not an electrical engineer. I'm a electronic's hobbyist that enjoys all forms of electrical/electronic 'stuff'.
 
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