Metek TWRF1 SCR Series, Instruction, Operation And Maintenance Manual

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TWRF1 SCR Power Controller Operation
Rev 2 Ametek HDR Power Systems 13
Figure 3.3 Process Controller Input Connections
d. Adjust the ZERO control CW until the output just turns on, then turn the ZERO control CCW just to
the point where the output voltage reading is zero.
e. Set the CUR/PWR potentiometer or Process controller to demand 100% output. Observing the
voltmeter, adjust SPAN CW just to the point where the reading is below the maximum output
voltage. Then adjust SPAN CW just to the point where the meter reading is at maximum.
f. Repeat steps 3.3e and 3.3f as necessary, to ensure proper control adjustments have been made.
g. Turn off the line power to the TWRF1 and disconnect the test equipment. The TWRF1 is now
ready for automatic operation.
h. Adjust the CUR/PWR potentiometer CW until the output trips to the desired level.
3.5 Auto/Manual Control with a Controller and Remote Potentiometer
On closed loop processes it may be desirable to be able to operate the unit manually. The SCR Power
Controller has this capability designed into it. Connect the Command Signal, a Remote Manual control
and an Auto/Manual switch in the Auto position. By switching to the Manual position, the Remote
Manual control operates and the auto signal is disconnected.
With the power to the TWRF1 turned off, connect the switch, potentiometer, and controller as shown in
Figure 3.4 and remove jumper from terminal TB1-7 and TB1-8. Install the
AUTO/MAN switch in the
same general location as the remote manual potentiometer. Note that the full CW position of the
potentiometer is the full-power-output position.
Figure 3.4 Auto/Man Control with Controller and Remote Potentiometer
Place the
AUTO/MAN switch to AUTO and calibrate the system as described in steps 3.3b through
3.3h.