Ametek SHPF3 Series, Instruction, Operation And Maintenance Manual

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SHPF3 SCR Power Controller Description
Rev 2 Ametek HDR Power Systems 3
CHAPTER 1 - Description
1.1 General Description
The SHPF3 is a Three-phase, phase-fired power controller, and can operate with a wide variety of
input signals and line voltages up to 575 Vac and currents ranging from 15 through 225 amperes. The
SHPF3’s output voltage is proportional to its input signal. The SHPF3 features pulse-train firing which
provides high immunity to possible SCR firing disturbances, and phase-lock loop circuitry which
ensures line frequency synchronization. Other features are input isolation from ground, soft-start, and
automatic restart circuitry. Terminals are provided to permit connection of a variety of external control
methods. A more detailed description of the features mentioned above is provided in Chapter 6 of this
manual.
1.2 Application
Phase-Fired SCR Power Controllers provide infinitely variable firing angles for precise control of three-
phase power to resistive or inductive loads. This precise control is essential for transformer coupled
loads or loads with great resistance changes due to temperature or start-up. Phase-Fired units may
also be used on straight resistive loads as well, but the lower power factor and higher harmonics may
present a problem to other equipment mounted nearby. A zero fired model would be a better choice.
1.3 Operation
The SHPF3 accomplishes power control by the switching action of a pair of inverse-parallel power
SCRs. The switching, or gating, of the SCRs is controlled by a digital firing control circuit synchronized
“in phase” with line frequency (either 50 or 60 Hz). A soft-start (approximately a 12 cycle ramp)
feature is standard that allows the Power Controller to fire into the primary of a transformer or to
control power to heating elements which have a large resistance change during start-up. The output
may be adjusted by the on-board multi-turn potentiometers or by a voltage or current signal from a
process controller. ZERO and SPAN controls allow the user to calibrate the SCR unit's output to the
process command signal. Terminals are available for connection of a remote manual potentiometer.
1.4 Specification
Specifications for the SHPF3 SCR power controller are given in Tables 1.1 and 1.2.
Table 1.1 SHPF3 Model Number Breakdown
SHPF3 – 480 – 180 – CR – UB – 01
NOTE:
N.O. Thermostat is included in current ratings above 60 A.
120 Vac -
120
240 Vac -
240
400 Vac -
400
480 Vac -
480
575 Vac -
575
15 A rms -
60
25 A rms -
60
30 A rms -
60
60 A rms -
60
90 A rms -
90
120 A rms -
120
180 A rms -
180
225 A rms -
225
N.O. Thermostat -
NO
N.C. Thermostat -
NC
RMS Current Limit/OC -
CL
RMS Current Reg/OC -
CR
Over Current Trip -
OC
True Power Reg/CL –
PR
Load Unbalance Alarm –
UB
Extended Ramp -
ER
Can have multiple selections
4-20 mA -
01
0-10 Vdc -
02
0-5 Vdc -
03
Auto/Man -
04
Manual Pot input -
05
Others -
xx