Increasing refiner production by using motor thermal capacity for protection and control
- Grainger Electrical Research Ltd., Edmonton, Alberta (Canada)
- Alberta Energy Co., Calgary, Alberta (Canada)
Industrial motors are typically controlled and operated by closely monitoring the stator winding temperatures and limiting the phase currents within the motor manufacturer`s full-load ampacity rating. A different approach to motor operation and control was implemented at the Blue Ridge Lumber medium density fiberboard (MDF) plant at Whitecourt, Alta., Canada. The capacity control of the refiner is based on using the remaining thermal capacity of the motor as the primary control parameter. In this installation, a 4,000-hp totally enclosed water air cooled (TEWAC) squirrel-cage induction motor is continuously operating above the manufacturer`s rated full-load current, but is being controlled by maintaining thermal capacity at 50%. Temporary current loadings well above this are permitted for up to several minutes to accommodate variations in the wood feed stock to the refiner. This was implemented by installing a modern motor protection relay, communication with a programmable logic controller (PLC) system, and the development of operator interface displays to provide plant operators with the necessary information to monitor the motor parameters. Factors which needed to be considered were the electrical power system limitations, the motor cooling effectiveness, and mechanical limitations imposed by the refiner shaft design.
- OSTI ID:
- 522381
- Journal Information:
- IEEE Transactions on Industry Applications, Vol. 33, Issue 3; Other Information: DN: Paper presented at the 1996 IEEE pulp and paper industry conference, June 10--14, Birmingham, AL (US); PBD: May-Jun 1997
- Country of Publication:
- United States
- Language:
- English
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