Transmittal of generator prepurchase specifications, March 1998

NYC 9/11 Public Portal Document

PPS-Generators

Hz), the frequency detector shall lockout the circuit breaker closing relay and simultaneously generate a DC voltage proportional to the frequency difference to cause the engine governor to bring the frequency within the preset acceptable limit. When the oncoming engine generator frequency is within the acceptable limit, the lockout shall be removed.

When the voltage and frequency limits are satisfied, and the relative phase angle between the oncoming unit and the bus reduces to 5 degrees approaching zero degrees, the synchronizer shall hold (phase lock) the generator output in synchronism with the bus, the circuit breaker closing relay shall close to initiate breaker closing and paralleling. DC control of the governor and voltage control shall be terminated simultaneously with breaker closure. The complete system shall function in such a manner as to insure that the maximum relative phase angle at the instant of paralleling does not exceed 5 electrical degrees.

6) Control Circuit Status Indicators

Color-coded, light-emitting diodes shall be provided on the generator sensing panel to indicate the control circuit status of the following conditions:

DC Input Power On Red Color Generator voltage and frequency acceptable Green Color Synchronizer Energized Green Color Selector Relay On Yellow Color Reverse power trip setting exceeded Yellow Color Generator Voltage Too High Red Color Generator Voltage Too Low Red Color Synchronizing Output Relay On Yellow Color Reverse Power Trip Setting Exceed for 2.0 sec; RPR Latched On Red Color

7) Engine Cooldown and Failure to Synchronize Time Delay Relays

OEM PPS-39 Generators 7 WTC March 20, 1998

NYC-WTC_000166914