Omega Products SCR-210A012U01 User Manual
SCR Power Controllers
For Electrical Resistance Heaters; 40, 60, 80 Amp
SCR19Z-24-060 shown without fuse, $310, shown much smaller than actual size.
SCR19 and SCR39 Series
Starts at
$
300
Zero Crossing or
Phase Angle Fired
Single- or 3-Phase
Load Switching
Extends Heater Life—
Reduces Thermal Shock
No Maintenance—
All Solid State Components
Close Control of Low
Mass Heaters
Phase Angle with
Soft Start for High
Inrush Heaters
No Relay Noise—Contact
Arc Noise Eliminated
2
Semiconductor I
T Fusing
Optically Isolated
4 to 20 mA Control
Signal Input
The SCR19 Series power controllers
are designed to proportion electric
power to resistive loads only, such
as ovens, furnaces, heat sealers,
etc. The controllers consist of power
semi-conductors (SCRs), properlysized heat sinks, trigger circuitry, and
fuses supplied on panels for surface
mounting.
drive transformers or any inductive load.)
The power controller accepts a
4 to 20 mAdc output from a
temperature controller or can be
supplied with manual option using
a remote potentiometer.
(Note: They are not designed to
Operation
The SCR19 Series controllers offers
2 methods of proportional control—
0-voltage-switched and phaseangled fired. With the 0 voltage
switching mode, the controller
switches on complete cycles of the
AC supply voltage. The trigger circuit
Dimensions: mm (in)
Model No. Height Width Depth
SCR19Z 178 (7) 121 (4.8) 102 (4)
SCR19P 178 (7) 121 (4.8) 102 (4)
SCR39Z 178 (7) 244 (9.6) 102 (4)
SCR39P 178 (7) 365 (14.4) 102 (4)
Note: When fuses are added to unit, add 83 mm (3.3") to height.
is designed to turn on the SCRs as
close as possible to the point where
the AC sine wave crosses through
zero. In effect, the line voltage
is turned on and off and applied to
the heaters in whole cycles. With an
input of 4 to 20 mA, the output will be
off below 4 mA and full on at 20 mA.
Proportioning action is obtained by
varying the number of cycles on to
the number of cycles off. The output
will vary from one cycle on and
9 cycles off at low input, to all cycles
on at maximum input. This output is
integrated by the heaters which
produce a smoothly proportioning
heat output that varies directly with
the input signal. With the phaseangle-fired mode, the power to the
load is controlled by governing the
point of turn-on (firing) of each half
cycle of the full AC sine wave.
Features
Designed to allow the operation
of multiple units by a single
temperature controller
P-119
Unique circuitry in the 3-phase
units allows any phase
connection—phases cannot be
incorrectly wired resulting in
partial output power on or off
Optical coupler ensures the
elimination of ground loops, highvoltage potentials, or damage to
drive controller of the SCR power
controller
Completely solid-state, SCR19
Series SCRs have no moving
parts to wear out. They are as
effective as new, even after
100,000,000 operations.
SCR19 Series SCRs offer smooth,
rapid, proportional heating action.
SCR control proportions only the
power required to maintain exact
temperature.
SCR19 Series SCRs eliminate
high/low cycling and, because the
temperature of the heating
element is constant, thermal shock
is eliminated. Heater life may be
increased by up to 7 times
6
Cycles
On
6
Cycles
Off
6
Cycles
Off
114 Cycles
On
117 Cycles
Off
114
120
= 95% Power Output
6
12
= 50% Power Output
0.2 Second
Time Base
2 Second
Time Base
2 Second
Time Base
3
Cycles
On
90°
Phase Angle of Triggering = 90°
Power = 50%
180°
Phase Angle of Triggering = 180°
Power = 100%
113°
Phase Angle of Triggering = 113°
Power = 25%
Extended Warranty
Program
SM
Specifications
Supply Voltage: 24 to 600 Vac
Frequency: 50 to 60 Hz
Current Rating: 40, 60, and 80 A
Control Signal Isolation: 2500 Vac
Transient Voltage Protection:
MOV and RC suppression
Ambient Temperature Range:
0 to 50°C (32 to 122°F) for listed
current rating
Load: Resistive, 3-phase, 3-wire, delta
or ungrounded wye SCR19Z
SCR19P: 1-phase, 1-line control
SCR39Z: 3-phase, 2-line control
SCR39P: 3-phase, 3-line control
Diagnostic Indicators: Shorted or open
SCR reversed signal input (mA/V)
Zero-Voltage Switching
Power is controlled by governing the
percentage of complete sine waves
to the load. The point of turn on in
the sine wave is at (or very near)
zero voltage, thus no RFI is
generated. SCR19 Series units
feature an infinitely variable time
base. They provide the ultimate
resolution in power proportioning to
the load. Also, because there are
no time base adjustments to make,
they are easy to use. The time base
is infinitely and automatically
adjusted while the SCR Power
Controller is operating from a
minimum 0.2 second time base at
half power output to a maximum
2 second time base at the 5% and
95% power outputs. See graphical
representation below. Power to
load = ratio of cycles absent to
cycles present in any number of
Zero Voltage
total cycles. An SCR19 Series
0-voltage-switched SCR power
controller with infinitely variable time
base provides maximum closeness
in temperature regulation by offering
higher power resolution than fixed
time base units, i.e., 20 cycle
fixed = 1⁄20 = 5% power change
minimum step change. Infinitely
variable time base units also
produce less power line disturbances.
OMEGACARESMextended
warranty program is available for
models shown on this page. Ask
your sales representative for full
details when placing an order.
OMEGACARE
labor and equivalent loaners.
Phase-Angled Fired
Power to load is controlled by
governing the point of turn on (firing)
of each half cycle of the full AC sine
wave (see example). After triggering,
the remainder of the AC cycle is
applied to the load. Phase-anglefired controllers are recommended
when controlling temperatures of
low-mass heating elements that
require high switching speeds, such
Phase Angle
SM
covers parts,
as tungsten elements, quartz lamps,
hot wires and other loads requiring
high inrush currents.
(Note: Some RFI can be generated from the
phase angle units.)
A soft-start timing circuit is available
that provides ramp to peak voltage
to limit the power to the load at
startup. Soft start action is required
for loads having high current, turnon characteristics, and slowly
P-120
changes the input signal from 4 to
20 mA when full output is required.
It is selectable from 9, 15, 30, 60 or
120 seconds. A voltage limit option
is also available which “clamps”
output power to a level lower than
supply power. The output power
is adjustable from approximately
20% to full output.
P
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