Transmittal of generator prepurchase specifications, March 1998

NYC 9/11 Public Portal Document

PPS-Generators

g- System Test Switch a Provide a system no-load test switch to initiate a complete automatic system operation by simulating the closure of the remote engine start signal. This switch shall be mounted inside the master section to limit access to authorized personnel only.

h. Master Audible Alarm

Provide a master audible alarm. The alarm horn shall be the DC vibration type, adjustable from 78 to 102db. Include an alarm silencing pushbutton and circuitry to allow subsequent malfunctions to resound the alarm if the horn had been previously silenced following an initial malfunction.

i. Load Demand Control

Load demand control logic shall be provided to sense the load connected to the bus and establish the proper number of sets to operate to maintain the connected load with the minimum on-line reserve generating capacity of 10% of the rating of a single set. The load demand control logic shall initiate the disconnection of a generator from the bus whenever the on­ line reserve generating capacity exceeds 120% of a single generator.

The load demand control logic shall have adjustable set points for initiating the addition to, and removal from, the bus of the generator sets. The load demand control logic shall be designed to maximize field economy while maintaining sufficient capacity to service the load.

Upon sensing that the on-line reserve capacity has increased to 120% or more, a 180 second time delay (adjustable 0-300 seconds) shall be initiated. If the reserve capacity stays above 120% for the duration of the time delay, the circuit breaker of the last set that went on line shall be opened. The engine shall run for its cooldown period, then shutdown.

j- Bus Load Optimization

If a generator fails while operating in the emergency mode, it is disconnected form the bus and shutdown. The lowest priority loads are shed. Audible and visual alarms will be activated to indicate the condition.

OEM PPS-33 Generators 7 WTC March 20, 1998

NYC-WTC_000166908