Ametek ZF2 SCR Series, Instruction, Operation And Maintenance Manual

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Options ZF2/ZF3 SCR Power Controller
6 Ametek HDR Power Systems Rev 3
CHAPTER 2 - Options
2.1 Option UB (Unbalance Alarm)
This option provides a Form C relay output for monitoring the balance of the 3 phase currents. This
options require current transformers (CTs). If the load currents become unbalanced by more than the
preset percentage, a Form C relay is actuated. Diagnostic indicators are also provided to indicate
operating conditions.
The load unbalance required to trigger an alarm is switch selectable and may be quickly reconfigured
in the field. Typical usage requires no field calibration, although precision trimming adjustments are
included to enhance the circuit’s sensitivity if small current unbalances are to be detected under
controlled conditions. Five light emitting diodes (LEDs) are provided to give a visual indication of the
board’s operation.
On models rated from 60 through 225 amperes the CTs are mounted in the controller and on models
rated from 350 amperes and higher, the CTs are shipped separately.
2.2 Option SF (Shorted SCR Failure Alarm)
This optional circuit monitors each SCR pair’s voltage drop and detects when an SCR is shorted.
Three green LEDs are lit when the SCRs are not shorted. If an SCR shorts, the respective green LED
will go out and the red alarm LED will light and the Form C relay will energize. Relay output and
terminals for connection are provided.
If the Unbalance alarm is provided Shorted SCR Alarm is a “piggy-back” board that mounts on the
Unbalance Alarm.
2.3 Option LG (Lug Kit)
Option LG will provide compression lugs for the 350-1200 A Power Controllers.
2.4 Additional Options
The options described above are the ones most commonly used. Additional options are available. For
more information, contact Ametek HDR Power Systems.