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 is amendment 3 to solicitation 9-BE13-27-8-21P which clarifies the following questions: 1) Please verify the motor speed constants: Cabin Fan Kv=1.8 Volts/KRPM; Water Pump Kv=2.65 Volts KRPM. Answer: The motor speed constants are correct. 2) Is non-hermetic (Gel-filled) hybrid circuit packaging acceptable? Answer: Acceptable if the part is either: A) Listed in the preferred parts list referenced in the solicitation, or B)Vendor can supply data to demonstrate that part is appropriate for the environment specs listed, reliability and traceability data for the part is available, and the gel is both positively contained and non-toxic. 3) Are opto-isolators acceptable? Answer: There are opto-couplers listed in the preferred parts list referenced. 4) Does NASA intend to have a controller and motor operate over the full range or do they expect to have one set at the low end (28 VDC) and one set at the high end (120 VDC)? Appendix A, para. 2.1 Cabin Fan/Water Pump Motor Control Assembly, the max. continuous current is specified without reference to a voltage at the motor. What is the assumed voltage for these current values? Answer: 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). 5)Appendix A, para. 2.1 Cabin Fan/Water Pump Motor Control Assembly, in what form are the Hall Sensor outputs to the motor controller, digital or analog? Answer: Hall sensor ouput is digital. (0114)

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