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SCR Power Controllers
For Electrical Resistance Heaters; 40, 60, 80 Amp
SCR19 and SCR39 Series
U Zero Crossing or
Phase Angle Fired
U Single- or 3-Phase
Load Switching
U Extends Heater Life—
Reduces Thermal Shock
U No Maintenance—
All Solid State Components
U Close Control of Low
Mass Heaters
U Phase Angle with
Soft Start for High
Inrush Heaters
U No Relay Noise—Contact
Arc Noise Eliminated
2
U Semiconductor I
T Fusing
U 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
SCR19Z-24-060 shown without fuse shown much smaller than actual size.
Dimensions: mm (inch)
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
U Designed to allow the operation
of multiple units by a single
temperature controller
U Unique circuitry in the 3-phase
units allows any phase
connection—phases cannot
be incorrectly wired resulting in
partial output power on or off
U Optical coupler ensures the
elimination of ground loops, highvoltage potentials, or damage to
drive controller of the SCR power
controller
U 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.
U SCR19 Series SCRs offer smooth,
rapid, proportional heating action.
SCR control proportions only the
power required to maintain exact
temperature.
U 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
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ZERO VOLTAGE
Power = 50%
PHASE ANGLE
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
SCR19Z: 3-phase, 3-wire, delta or
ungrounded wye
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
total cycles. An SCR19 Series
Zero Voltage
2 Second
Time Base
114 Cycles
On
114
= 95% Power Output
120
Time Base
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.
0.2 Second
Time Base
6
Cycles
Off
2 Second
6
Cycles
On
6
= 50% Power Output
12
Cycles
6
Off
OMEGACARESM extended
SM
warranty program is available for
models shown on this page. Ask
Extended Warranty
Program
your sales representative for full
details when placing an order.
OMEGACARE
labor and equivalent loaners.
SM
covers parts,
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
3
Cycles
On
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,
turn-on characteristics, and slowly
117 Cycles
Off
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
180°
Phase Angle of Tr iggering = 180°
Power = 100%
Phase Angle of Tr iggering = 90°
113°
Phase Angle of Tr iggering = 113°
Power = 25%
90°
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(*) Specify Line Voltage
Code Description
02 24 Vac
12 120 Vac
20 208 Vac
24 240 Vac
48 480 Vac
(**) Soft Start or Voltage Limit
Code Description
S9 Soft start 9 seconds
S15 Soft start 15 seconds
S30 Soft start 30 seconds
S60 Soft start 60 seconds
S120 Soft start 120 seconds
V Voltage limit
X No soft start or voltage limit
Note: Soft start with phase angle only.
SCR19Z-24-060 shown
without fuse shown smaller
than actual size.
Replacement Fuses for SCR19 Series
Model No. Current (A)
SCR-210A015U01 40
SCR-210A012U01 60
SCR-210A014U01 80
Phase-Angle Firing Models
To Order Visit omega.com/scr19 for Pricing and Details
Model Number Current Load (A) Weight kg (lb)
Single-Phase Models
SCR19P-(*)-040-(**) 40 1.4 (3)
SCR19P-(*)-060-(**) 60 1.4 (3)
SCR19P-(*)-080-(**) 80 1.4 (3)
3-Phase Models
SCR39P-(*)-040-(**) 40 4.1 (9)
SCR39P-(*)-060-(**) 60 4.1 (9)
SCR39P-(*)-080-(**) 80 4.1 (9)
Comes complete with operator’s manual.
To order a unit with manual input option module and remote pot, add suffix “-M” to model number for an additional cost.
Ordering Examples: SCR19P-24-060-S30, 60 A, 240 V single-phase model with a 30 second soft start option.
OCW-3, OMEGACARESM extends standard 2-year warranty to a total of 5 years.
SCR39P-48-040-S9, 40 A, 480 V single-phase model with a 9 second soft start option.
Zero-Voltage Switching Models
Wt. Current
Model No. Model No. Model No. kg (lb) (A)
120 V Single-Phase 240V Single-Phase 480 Single-Phase
SCR19Z-12-040 SCR19Z-24-040 SCR19Z-48-040 1.4 (3) 40
SCR19Z-12-060 SCR19Z-24-060 SCR19Z-48-060 1.4 (3) 60
SCR19Z-12-080 SCR19Z-24-080 SCR19Z-48-080 1.4 (3) 80
240V 3-Phase 480 3-Phase
— SCR39Z-24-040 SCR39Z-48-040 2.7 (6) 40
— SCR39Z-24-060 SCR39Z-48-060 2.7 (6) 60
— SCR39Z-24-080 SCR39Z-48-080 2.7 (6) 80
All phase-angle and 0 voltage models come complete with operator’s manual and 1 fuse per SCR line controlled.
Note: To order a unit with manual input option module and remote pot, add suffix “-M” to model number for an additional cost.
Ordering Examples: SCR19Z-24-060-M, 60 A, 240V single-phase model with optional manual potentiometer input.
SCR39Z-24-080, 80 A, 240V 3 phase model.
P-121
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