Watlow QPAC Modular SCR Power Control Service - Manual (Page 3)

WATLOW QPAC Service Manual
3 Contents
Contents
Table of Contents
Chapter 1 QPAC Modular SCR Power Control Page
General Description .................................................................... 4
Overview ..................................................................................... 5
Replacement Parts ...................................................................... 5
Indication of Malfunction ............................................................. 5
QPAC Specifications ................................................................... 6
Chapter 2 Preventative Maintenance
Cleaning Cooling Fans, Fins and Filter ....................................... 8
Tightening Connections .............................................................. 8
Periodic Test Runs ...................................................................... 8
Chapter 3 Operation Theory of Base and Firing Cards
Single Phase Model - Q01 .......................................................... 9
Power Base Operation ................................................................ 9
Three Phase, Two Leg - Q32 .................................................... 10
Power Base Operation .............................................................. 10
Three Phase, Three Leg - Q33 ................................................. 11
Power Base Operation .............................................................. 11
Zero Cross Control Cards ......................................................... 13
Chapter 4 Test Procedures
Q01 and Q32 ............................................................................. 15
Q33 Zero Cross Adjustment ...................................................... 15
Bias and/or Gain Adjustments ................................................... 16
Current Limit Adjustments ......................................................... 16
Chapter 5 Troubleshooting
Indications of Malfunction .......................................................... 17
Troubleshooting Guidelines ...................................................... 17
Q01 Troubleshooting ................................................................. 18
Q32 Troubleshooting ................................................................. 21
Q33 Troubleshooting ................................................................. 24
Bench Testing ........................................................................... 27
Testing SCRs in the Unit ........................................................... 28
Installing an SCR Package ....................................................... 28
Troubleshooting the Base and Control Cards ........................... 28
Appendix
Waveforms and Schematics ..................................................... 31