Attachments to CAT Chat Minutes - March 15, 2004
W. Wesolowski
Attachment 2


img1Minimum Generator Start and Transfer Times

Greg Markovich     1/15/2004

Voltage event below ~80% of nominal for ?? milliseconds triggers ATS to start generator. (ATS has the programmable equipment that monitors the voltage and starts the generator)


Generator ready for load

If the voltage is still below the threshold setting, the ATS will transfer the loads to the generator. The loads will remain on the generator until the utility has been verified stable for 10 minutes at which point the ATS will transfer the loads back to the utility. If the utility stabilized itself before this time, the loads will not transfer, the generator will run through its minimum run period and shut itself down.

How long does the power have to be off before generators are started?
Voltage must be below ~80% nominal for ?? mS (note the mS. Not seconds)

Is that basically how long the normal power has to be off   before generators kick on?
Generator starts immediately but isn't ready for load for a minimum of 10 seconds

Also what if there is transients where normal power flickers on and off several times before it stays off?
Once the generator gets a signal to start, it runs a minimum of 15 minutes at voltage. So, if another event occurs below the threshold during this 15 min period, the transfer to e-power is 0.5 seconds, the time it takes to mechanically switch over.