Ametek SHPF3 Series, Инструкция по эксплуатации и техническому обслуживанию

Страница: 11 / 40

SHPF3 SCR Power Controller Options
Rev 2 Ametek HDR Power Systems 5
CHAPTER 2 - Options
2.1 General
Several options are available from Ametek HDR Power Systems, and are described below. Most
options require current transformers (CTs), which are optional. 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 OC (Three-Phase Overcurrent Trip)
The Three-Phase Overcurrent Trip Option (OC) provides circuit protection from output current
overloads by serving as a fast-gate shutdown. (Option OC functions similar to an electronic fuse.)
Trip point is adjustable from 30% to 200% of the SCR Power Control’s current transformer rating.
Current transformers on the SCR Power Control’s output lines allow Option OC to monitor
instantaneous peak current. When the peak current level exceeds the preset trip level, SCRs are
gated off, and the load current is shut down within 1/2 cycle. The TRIP RESET pushbutton must be
manually reset to resume operation.
Another feature of the overcurrent trip is an automatic reset. This is included with the current limit and
current regulation. Open the unit and locate the auto reset switch and reset pushbutton. With this
switch in the on position, the unit will continue to reset until the fault clears. If in the off position, the
unit will remain shut off until the reset PB is operated. The auto reset switch will always be in the off
position unless specified on the order.
The overcurrent trip option includes a Form C relay output and provisions for a remote overcurrent
reset push button. The relay output terminals are 39 and 40 for the N.C. and 40 and 41 for the N.O.
The remote reset terminals are 37 and 38. Reference Figure 5.1.
2.3 Option CL/OC (Current Limit/Overcurrent Trip)
The Three-Phase Current Limit Option (CL) prevents the output current of an SCR Power Control from
exceeding a preset maximum current level, as determined by the current limit control setting (30% to
125%). This option also includes an OC trip with Form C relay output contact and terminals for
connection of a remote OC reset pushbutton. The current limit adjustment is on the front of the unit,
while the overcurrent trip adjustment is located on the current regulation PCB on the inside of the unit.
A current transformer monitors the true RMS current, and feeds the information to Option CL, which
limits the true RMS current regardless of the process control signal. Current Limit is adjustable from
30% to 125% of the CT rating.
2.4 Option CR/OC (Current Regulation/Overcurrent Trip)
The Current Regulation option is much like the Current Limit. It includes an overcurrent trip feature, but
regulates the RMS current rather than limiting it. The adjustment range is 30 to 125% of the unit's
rating for the current regulation and 30 to 200% for the overcurrent trip. This option also includes an
OC trip with Form C relay output contact and terminals for connection of a remote OC reset
pushbutton. The current regulation adjustment is on the front of the unit, while the overcurrent trip
adjustment is located on the current regulation PCB on the inside of the unit.
The Three-Phase Current Regulation Option (CR) compares the feedback signal to the control signal,
so the line current will be linear to the control signal, and regulated to maintain a constant level at the
controller output despite load changed. Current regulation is adjustable from 30% to 125% of the CT
rating.