Miniature Centrifugal Compressor Development

• Kevin Finney• Ray Zhou• Xiaoyi Li• Krishna Murty

November 22, 2002

Current Status• Motor

– Motor and controller have been delivered…– Methods to cool motor being considered…

• Compressor Parts– Parts with blades have been sent to machine shop in

California for a price quote. You ask, “why California?”

• Assembly of Compressor– Jig fixtures needed for assembly are ready to be

machined. Waiting to see if the compressor parts can be machined in California.

• Safety Shield– Design and construction of the safety shield complete

Motor Update• Received the motor

– Motor brackets can be designed and built now. Can include integrated cooling jacket.

– Need to obtain an adjustable power supply and solder the wires to the wire leads.

– Motor requirements given in following table…

150,000 rpm no load requires 33 Volts and 6.8 amps150,000 rpm with 300 Watts output requires 27.89 amps

Therefore, to obtain the desirable speed and power…Voltage Current Electrical_Power 33V 27.89 A 920.37W

Electrical_Power Shaft_Power Heat 920.37W 300W 620.37W

Heat 620.37W

Methods to Cool Motor

• Reasonable choices– Use chilled water lines in laboratory– Use external chilling system

• Water jacket being designed now to surround motor and remove heat.

Need to remove 620 Watts of heat.

Compressor Parts• Machine shop in Sanford determined they

weren’t capable of machining the parts with blades.

• Been determined that a five axis simultaneous movement CNC mill required. Recommended to find a company with a Deckel Maho CNC Mill.

• “WHY CALIFORNIA?” – Machine is difficult to locate– When located, difficult to spark interest for such

limited quantity of parts.• Wessdel Manufacturing and Engineering in

Santa Clara, CA showed interest.

Compressor Parts Update• Prepared surface and wireframe iges files of the

three parts with the blades.• Sent the files and the 3 plastic models to

Wessdel Manufacturing and Engineering.• Will have a quote prepared by the first of next

week.• Much more interactive company… Wanted me

to specify:– Radius at root of blade and hub– Scallop height allowable of material between blades– Tolerance allowable of the blades

Status of Jig Fixtures for Assembly

• Parts required for mounting of bearings and assembly of compressor will be machined once the Impeller, Diffuser, and Guide Vane are being machined.

• The jig fixture parts aren’t needed until the compressor parts are acquired.

Safety Shield Status

Project Status• Parts Acquired

– Bearings– Coupler for low RPM– Motor and controller– Non-bladed

compressor parts– Safety shield

• Parts Desired– Adjustable power

supply– Bladed compressor

parts– Cooling system– Coupler for high RPM– Measuring devices for

required measurements