Original Date: 06/23/1997
Revision Date: 01/18/2007

In an effort to reduce costs and improve turnaround time to the customer, Letterkenny Army Depot (LEAD) developed a repair procedure to facilitate the repair of the coolant pump motor/impeller rotor shaft used on the Phased Array Tracking to Interception of Target (PATRIOT) Radar Set coolant pump assembly. Prior to adopting this procedure, repairs to this unit were limited to the replacement of seals, packing, and motor bearings. Any damage or wear to the motor rotor shaft required the entire motor assembly be scrapped and replaced at a cost of just over $11 thousand, since the rotor shaft was not an individual replacement component.

Through the use of reverse engineering of the coolant pump rotor shaft, a repair procedure was developed by LEAD. This procedure incorporates the use of Tungston Inert Gas welding and/or selective copper plating of the worn or damaged areas of the shaft once these areas are pre-machined. After welding and/or plating (depending on the extent of wear or damage) the repaired areas of the shaft are remachined to required specifications. The rotor shaft is then reassembled into the coolant pump assembly, and the assembled unit is tested to ensure proper operation.

By applying this repair procedure, LEAD reduced the cost of the repairs to the coolant pump assembly from just over $11 thousand to an average of $500 per unit. The Depot also expanded the repairs of this unit to include the rewinding of the pump motor when required.

For more information see the Point of Contact for this survey.