WSP12132 - Laserfiche WebLink

Home Browse Search

MAINTENANCE UPDATE How to Avoid Burnout . The Granby Motor Rewind Project What do you do with three large. 6,000 horsepower heavily used pump plant mOlors beginning to show the effects of 40 years of wear and lear? In the case of the NCWCD. wIth the motors in question essential to Colorado-Big Thompson Project operations. you either replace them completely or rejuvenate their life through a process known as motor rewinding. After extensive study the District determined that the latter was the best alternative. So why should water users be concerned? Because by rewinding the motors the NCWCD is not only insuring the continued ability of the system to deliver water to northeastern Colorado, but also is doing so in the most economical way possible. Built almost 40 years ago by General Electric. the three Granby Pump Plant motors are otten referred to as the "heart" of the C"BT system. Without these molors and their ability to pump large Quantities of water into Shadow Mountain Reservoir and Grand Lake. much of the waler collected on the west slope could not be delivered through the Adams Tunnel to northeastern Colorado. Insulation integrlly tests. completed every 5 years to indicate how well the motors have worn, came back In late 1989 shOWing considerable deterioration. Rewinding would be necessary to prevent the motors from failing complelely forCIng an expensive replacement process. In addition, total replacement would warrant substanllally more down time than rewinding. ReplaCing the motors would not only cost significantly more (on the magnitude of twice as much) but would also require substantial reconstruction within the pump plant itself. An evaluation committee was established that determined a motor rewind project to be the best alternative. This committee sent solicltallons of interest to over 20 firms nationwIde. From this. four firms expressed an Interest in bidding on the rewind contract. General Electric, the original pump and motor contractor in 1952, was awarded the $1.8 million contract following a lengthy review process_ personneJ who then were responsible for installing the new components_ The rewind of pump number 1 was completed in September. Acceptance testing and reassembly is anticipated to take approximately two months. The rewind of pump number 2 will begin in January and will last 3-4 months. Pump number 3 is scheduled for rewinding beginning in July With the entire project to be completed by December 1991. Noble Underbnnk, Granby Pump Plant Superintendent. is pleased with the rewind project so far. "All in all it is going Quite well. although some of . GE TechmClan plaCing coli Into slot. Each of the 216 coils are IndJVidually placed and wedged rnto tfle 51015 In order to insure that two pumps will always be available for pumping throughout the rewind prOject il was decided to tear down one pump at a lime. With a contract approved by the Dlslrlct Board of Directors in February. work on the first pump began In July_ NCWCD crews disassembled the motor for GE the work is tedious and can be very time consuming." he said. The reassembly is a painstaking process requiring over 180 different readings to be taken while realigning the motor to the shaft. But as Underbrink points out, '1hat's a small price to pay to extend the motors usefulness another 50-60 years.~ . '0 WATERNEWS FALL 1990