CG-PY2400 Frequency Control
Pump Points 3-13-92 R. E. Merrill and Assoc. Inc.
Frequency control use with CG-PY2400
Texas Instruments installed two CG-PY2400 pumps on a 1,000-gallon variable flow process waste tank. The flow rates of which, from microprocessor clean rooms, vary with production demands.
The design criteria called for a continuously operating pump as opposed to a stop/start operation. The pump needed to slow as flow rates to the tank decreased and speed up as flow rates increased. To accomplish this, level sensors were installed in the tank that transmit a 4 – 20 mA signal to a motor adjustable frequency drive which regulates the motor rpm.
As a result, the 2400’s operate smoothly over a wide rpm range. The advantage was realized in decreased stress on both the pump bearing and seal, from frequent high torque startups. Additionally, a significant energy cost savings was realized.
Motor frequency drives are a helpful step toward environmental conservation as well as energy reduction. Additionally, higher head ranges could be reached by installing 3600 rpm motors and operating at say 2100 rpm without loss of motor torque.
This would accomplish two things. One, keep the shaft rpm low for long shaft verticals. Two, reduce power consumption. Energy savings often result in a one year pay back for the frequency drive. (Savings can be computed using the affinity laws and customer KW costs.)
Increased head ranges without operating a 3600-rpm motor with trimmed impellers is what attracts users to Vanton pumps. The customer will realize a pay back in energy savings and the prospect of longer pump life (less down time) due to stress reduction on the pump itself.