General Question and Answer for FBO.doc

REQUEST FOR PROPOSAL (RFP) FA8533-08-R-25855

250 kW MOTOR GENERATOR PROGRAM

QUESTION AND ANSWER FOR

INTERESTED SOURCES

The 642d Combat Sustainment Group Major Programs Contracting Office received the following question on the above referenced RFP. Recognizing the answer’s benefit for all interested sources, the following information is provided on FedBizOpps.

Question:

Paragraph 4.5.2.4 of the PD requires the MG set to be tested in accordance with MIL-STD-70C Method 505.3c for over speed verification.

Since the Motor on the MG set is a synchronous motor, the speed is determined by the incoming frequency. Since utility power is at 60HZ, this would translate to 1200 RPM of the MG. In order to do the over speed test the MG needs to be at 1500 RPM which would require the incoming utility power to be 75HZ. No one can control the incoming utility frequency, except the utility.

Please advise if the Air Force still requires the test?

Answer:

Paragraph 4.6.2.4 (Overspeed) states, "The generator shall be tested in accordance with MIL-STD-705C, Method 505.3c to verify compliance with 3.2", which is 125% for 15 minutes (reference paragraph 3.2). Note this is a test of the generator only, not the motor, and the premise of the test is to verify correct balance of the rotating parts of the generator. This test (along with the other tests and inspections of 4.6.2.1 of 4.6.2.7) does not have to be performed at the prime contractors facility on the completed motor generator set but may be performed at the motor/generator manufacturers facility on the subcomponents. Note that the motor may or may not be attached (depending on the design configuration) for the test and that test requires the generator to produce 115/200 VAC at 400 Hz but there is no electrical load applied for the entire test duration. A variable frequency electrical or mechanical power source connected to the generator rotor is highly recommended, because as stated below, the utility power source frequency will not be changing 25%.

Point of Contact: Kyle Hering, 642 CBSG/GBKBB, Robins AFB GA (478) 222-1891