Transmittal of generator prepurchase specifications, March 1998

NYC 9/11 Public Portal Document

PPS-Generators

b. Manual Paralleling Controls

A selector switch shall be provided to select any generator for manual paralleling. The switch shall simultaneously connect a phase band mopitor, synchroscope and manual paralleling pushbutton switch to the selected generator.

A solid sute Synchronizing Phase band Monitor, Device 25C, shall be furnished a sync check relay for manual paralleling, pushbutton until the oncoming generator is within 15 degrees of synchronism.

Operation shall be arranged so that the operator will depress and hold the manual paralleling pushbutton switch. When the relative phase angle reduces to 15 degrees and is going toward zero degrees. Device 25C will initiate the closing of the respective oncoming generator breaker. The manual paralleling pushbutton switch shall be connected to the selected generator by the synchroscope selector switch. All controls and metering for manual paralleling shall be grouped in a central convenient location on the font of the master control section.

c. DC Control Power Selector - Best Battery System

1) Each generator control unit shall utilize the engine starting batteries, and a DC-to-DC converter for each engine generator to provide a 24 Vdc power supply to the generator control PLC power supply, as backup, during starting and cranking of all engine generator sets "simultaneously".

2) Control power for the system logic shall be derived from the engine starting batteries and a separately supplied DC station battery system. The control logic shall be powered through a suitable means which shall permit continuity of power until the last battery is on longer available. The controls shall be powered from any battery or combination of batteries and prevent feedback to a failing battery. The transition of control logic power from any battery combination to any other battery combination shall be accomplished without disruption in the power flow. A system logic DC-to-DC converter, shall be supplied to provide a 24Vdc power supply to the system logic PLC power supply, as backup, during starting and cranking all engine generator sets "simultaneously". The DC-to-DC converter shall not permit the voltage to drop below the 24Vdc nominal.

OEM PPS-31 Generators 7 WTC March 20, 1998

NYC-WTC_000166906