NASA/Lyndon B. Johnson Space Center, Houston Texas, 77058-3696, Mail Code: BE

16 -- BRUSHLESS DC MOTORS SOL 9-BE13-27-8-21P DUE 050198 POC Wendy L. Boudreaux, Contract Specialist, Phone (281) 483-5338, Fax (281) 244-5331, Email wendy.l.boudreaux1@jsc.nasa.gov -- Lisa Rea-Phillips, Contracting Officer, Phone (281) 483-8395, Fax (281) 244-5337, Email lisa.r.phillips1@jsc.nasa.gov WEB: Click here for the latest information about this notice, http://nais.nasa.gov/EPS/JSC/date.html#9-BE13-27-8-21P. E-MAIL: Wendy L. Boudreaux, wendy.l.boudreaux1@jsc.nasa.gov. This Amendment No. 2 provides answers to questions on solicitation 9-BE13-27-8-21P for the Brushless DC Motor Controllers. 1) The requirements of input voltage of 24-130 VDC and max continuous current of 30 amps will drive the design to be sized for 4 KVA. Please clarify whether the input voltage range of 24-130 is the broad requirements or whether the controller can be sized to meet either a nominal 28 VDC or nominal 120 VDC input voltage. The controller will be used to operate a nominal 28 VDC motor, with 30 amp max load. If it can be reasonably achieved, NASA would like to preserve the option to use the same controller to power a nominal 120 VDC motor. If this is done, the load current would decrease proportionally (ie, would drop to 7 amps). If it believed that this desire to extend the input voltage to 130 VDC adds significant complexity/cost to the controller design, please so state and provide a proposal for a controller which operates only with nominal 28 VDC motors (ie, 24 to 32 VDC input range). 2) Define the vehicles power source. Normal power source will be 24 to 32 VDC as supplied by batteries. 3) Define the power interface characteristics; i.e. steady state voltage range, source impedance, abnormal operating voltage, broadband voltage ripple, et. Power source will be in the range of 24 to 32 VDC. The specific source impedance and maximum voltage ripples have not been defined. 4) Please confirm that both the Cabin Fan Motor and the Water Pump Motor can be supplied as GFE for test purposes. NASA can loan a representative fan and pump for testing. 5) How many connectors are on the motor; i.e. power, hall-effects, thermistor, etc. There are a total of 10 connections to the motor (3 winding, 3 hall, hall power, hall return, 2 thermistor). 6) Please define the cable length between the motor controller and the motor for both the cabin fan and water pump applications. Exact cable length is not defined -- assume between 3 and 6 feet. 7) Define the controller envelope (LxWxH). There is no specific envelope required, however it would be desirable to stay within an 8 inch X 8 inch X 6 inch envelope. 8) Please define the LET (latent energy transfer) level for immunity as stated in Paragraph 1.7 radiation. The supplier shall take proper precautions such that a single event effect cannot cause any permanent/un-recoverable damage to the controller. This can be addressed by using components which are completely immune to single event effects, or taking other precautions in the system design such as current limiting for sensitive components, etc.. If controller design is susceptible to transient single event upsets which cause no permanent damage (are either automatically cleared by the controller, or require external power cycle to clear), the corresponding Linear Energy Transfer Threshold (LETth) should be identified by the supplier. 9) Please confirm that EEE part traceability is not a requirement for this procurement of motor controllers. NASA prefers that grade 2 (or better) parts be selected in accordancewith the publication listed in the solicitation. Supplier may propose use of alternate (e.g., commercial) parts, however NASA will require that supplier furnish appropriate environmental and reliability data for the part or parts line, and that some form of traceability exist to verify that the data applies to actual parts being used. (0105)

Loren Data Corp. http://www.ld.com (SYN# 0159 19980417\16-0011.SOL)