Lumber/Paper - Special Needs
Processing trees into lumber and paper requires large motors. The motors must handle heavy trees, drive conveyor belts and saw blades, and pump thousands of gallons per minute. They must stir pulp mixtures and roll up miles of paper products.
Most of the time, they are controlled by computers. In these conditions, voltage stability becomes very important, and often, very difficult to maintain. If the computer controlling a process has a glitch, then the entire process may shutdown costing tens of thousands of dollars.
As more variable speed drives replace standard motors, voltage levels and current harmonic distortion increase. This can cause excessive motor vibration, stress on the motor shafts, and premature failure on standard motors nearby. The current distortion can cause overheating of transformers and conductors. If these symptoms are seen, a harmonic study is in order.