Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual page 106

ELECTRIC CONTROL FUNDAMENTALS
Series 90 Control Circuits
Motor Control Circuits
............................................................................................................ 107
Application ........................................................................................... 107
Equipment ........................................................................................... 107
Controllers ....................................................................................... 107
Actuators ......................................................................................... 107
Operation ............................................................................................. 108
General ........................................................................................... 108
Bridge Circuit Theory ...................................................................... 108
Basic Bridge Circuit .................................................................... 108
Bridge Circuit in Balanced Condition ...................................... 108
Bridge Circuit on Increase in Controlled Variable ................... 108
Bridge Circuit on Decrease in Controlled Variable ................. 109
Bridge Circuit with Limit Controls ........................................... 109
Bridge Circuit with Low-Limit Control ..................................... 110
Bridge Circuit with High-Limit Control ..................................... 110
Control Combinations .......................................................................... 111
Low-Limit Control ............................................................................ 111
High-Limit Control ........................................................................... 111
Two-Position Limit Control ............................................................... 112
Manual and Automatic Switching .................................................... 112
Closing the Actuator with a Manual Switch ................................. 112
Transferring Actuator Control from
One Thermostat to Another .................................................... 112
Reversing for Heating and Cooling Control ................................ 112
Transferring Controller from
One Actuator to Another ......................................................... 113
Unison Control ..................................................................................... 113
Manual Minimum Positioning of Outdoor Air Damper ......................... 113
Step Controllers ................................................................................... 114
............................................................................................................ 114
Application ........................................................................................... 114
Equipment ........................................................................................... 114
Starters ........................................................................................... 114
Contactors and Relays .................................................................... 114
Operation ............................................................................................. 115
Momentary Start-Stop Circuit ......................................................... 115
Hand-Off-Auto Start-Stop Circuit .................................................... 115
Momentary Fast-Slow-Off Start-Stop Circuit ................................... 116
Control Combinations .......................................................................... 117
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ENGINEERING MANUAL OF AUTOMATIC CONTROL