nonelectrical

Technical
WR-6161, WR-6172
2-Wire HID Relays
2-WIRE RELAY TECHNOLOGY
• Douglas 2-wire relays utilize an ingenious control method that
permits simple and minimal wiring. All functions for low voltage
control: on, off, indication and location are provided with
only a 2-wire connection of which one is often a common. All
Douglas relays manufactured over the past 30 years utilize the
same principle. Thus, any Douglas switching device is
compatible with any model of Douglas relay.
Manual
Lever
Detailed 2-wire Relay / Switch Circuit
Transformer
24VAC
W
B
Blue
White
2-wire Switch
Switch
Operational Principle
• A negative pulse turns the relay ON and a positive pulse turns it
OFF. Using a diode, an AC signal can be rectified to turn the relay
either ON or OFF. Douglas switches have 2 diodes built into the
switch to provide the ON and OFF signals.
• The relay has 2 similar diodes built inside that are in series with the
relay coil. The diodes in the relay act as gates for the switch signal.
• To turn the relay ON or OFF, the rocker switch completes the circuit
by selecting the ON or OFF diode. If the diode selected is in the
same direction as the gate diode in the relay, the relay will switch. If
the gate diode is not in the correct direction, then nothing will
happen since the relay is already in the correct state for the action
selected by the switch. When the switch is released, a spring returns
it to the central neutral position .
• Indication (ON state) and location (OFF state) are obtained by
utilizing LED diodes built into the switch. Only the LED which is
connected in the same direction as the gate diode in the relay will
light. Although the LED current passes through the relay coil, it is
not large enough to cause the relay to trip. However, there is a limit:
the maximum number of LED switches that can be connected to the
same relay is . 6
• For additional convenience (especially during installation) all standard
models have a manual control lever and indicator permitting a nonelectrical
method of switching and status check at the panel.
Latch to lock relay ON
or OFF (actually done
with magnetics)
Tr
Tr
W
B
Relay
W
B
2-wire
Relay
Gate Diodes
Relay Coil
Red
Control Diodes
Switch
Switching ON
Switch pressed to ON position.
ON pulse ( ) sent to relay and
relay begins to switch over to ON .
Switch
Detailed LED Switch Circuit *
Transformer
24VAC
W
B
Blue
White
LED 2-wire Switch
ON
ON
Relay
Switched ON
Relay completed switching to ON position.
OFF gate diode engaged and ON pulse
from switch is stopped by OFF gate diode.
Relay ready for OFF pulse.
2-wire Relay
Red
Gate Diodes
Relay Coil
OFF
OFF
Control
Diodes
LED
Indicator Diodes
Current limiting
Resistor
Tr
W
B
Switch
*
LED Switch circuit actually not
as shown. Switch is functionally
similar except rocker switch is
replaced with single push button.
Relay
Switching OFF
Switch pressed to OFF position.
OFF pulse ( ) sent to relay and
relay begins to switch over to OFF.
Components 1.2
A-1.1,2,3,4 -Relays & Panels, HID
www.DouglasLightingControls.com

Technical
Relay Panels for HID Relays
PWEx Panels
PART No.
PWEx Panels
DESCRIPTION
• Douglas PWEx series relay
panels are a versatile line of
panels used for WR-6161 &
WR-6172 relays.
• Standard sizes range from 6 - 72
relays. (Note:WR-6172= 2 relays).
• A panel consists of the enclosure
(tub), the interior and the cover.
Enclosures are installed in the
rough-in stage and interiors are
installed and connected after
wires are pulled.
• Interior has snap brackets for
mounting relays and DIN rail in
the centre for mounting control
components.
• Box knockouts are located so that
panels of the same horizontal or
vertical dimension can be joined
with conduit nipples.
SPECIFICATION
• Enclosures and covers are made
of steel coated with ANSI/ASA
61 Grey. Coating is heat fused
polyesther epoxy finish applied
on all surfaces.
• Interior insert is made from
aluminum, stell and plastic parts.
Certifications
• UL listed, CSA approved.
EEMAC/NEMA 1 Standard.
Options
• Hinged, surface or flush covers.
Covers are reversable for either
left-to-right or right-to-left door
opening. Driphoods (surface
mount only). NEMA 3 standards.
Special paint colors. Voltage
dividers to divide line voltage
compartment for different line
voltages.
4"
4"
Compartment Style
Barrier Layout
4"
CAPACITY
6 12 24
PART No.
PWE0 - C06M - ** PWE1 - C12M - ** PWE2 - C24M - **
SIZE (H x W x D)
12 x 12 x 4.25 20 x 14 x 4.25 33 x 14 x 4.25
PWEx Panel Numbering System
** Add cover style number at end of P/N
Enclosure
PWEx
C
W
Interior
xx
M
S1
F2
Cover
or
S3
F4
4½"
3"
Box Code
Barrier Layout
Compartment: C
Wireway: W
Capacity
Relay Code
HID relays: M
Screw-on
Surface: S1
Flush: F2
Hinged
Surface: S3
Flush: F4
4½"
3"
4½"
3"
4½"
3"
Symbols
Low voltage area
Line voltage area
HID relay
Transformer
Wireway Style
Barrier Layout
CAPACITY
PART No.
SIZE (H x W x D)
6"
24
PWE3 - W24M - **
27 x 20 x 4.25
6" 6"
36 48 72
PWE4 - W36M - ** PWE6 - W48M - ** PWE8 - W72M - **
33 x 20 x 4.25
** Add cover style number at end of P/N
39 x 20 x 4.25
7"
54 x 20 x 4.25
Components 1.3
A-1.1,2,3,4 -Relays & Panels, HID
www.DouglasLightingControls.com

Technical
Relay Panels for HID Relays
PWEx Panels
PWEx Panels: Exploded View
Drip Shields
Optional, surface cover
panels only.
Screw-on
Covers
Hinged Covers
Surface (S1) or
Surface (S3) or Flush (F4). Flush (F2)
Install right side up or upside down
for right-to-left or left-to-right door.
The inner trim of the hinged cover
covers over all of the line voltage wiring.
Access to the relay's manual control
levers is in the low voltage compartment.
Relay Interior
Relays mount to HID snap rails.
Barriers are located to provide the
line / low voltage division.
Transformers mount to 1/2" knock
outs located in the barrier.
Control components are mounted
to DIN rail in center of interior.
Pre-assembled PWEx panels will
have panel schedules completed
according to information provided
and all low voltage control
connections pre-wired.
INSTALLATION & ASSEMBLY
PWEx series relay panels for Douglas HID relays are supplied
with a separate interior. All of the components and barriers are
mounted to the interior.
Stacking Panels
Panels of equal dimension on a
side have matching KO pattern
to provide easy stacking.
PWEx panels are primarily intended for projects where the interior
is factory pre-assembled. To install the relay panel the following
sequence is recommended:
1) Mount the empty enclosure onto the wall and pull wires. It is
recommended that all (or most) of the wires be pulled prior to
installing the interior. This will prevent component damage
from the wire pulling operation.
2) Relay line voltage terminals are sized for a maximum of
12AWG wire.
For low voltage wiring 18AWG solid is recommended.
3) Once the wires have been pulled, install the interior and bolt it
into place. Make line connections to relays according to the
panel schedule provided. If there is no schedule, identify
circuits on a blank schedule.
4) To test circuit, turn circuit breaker off, use manual lever to turn
relay on and then turn on the circuit breaker. This will help
prevent relay contact welding due to dead shorts.
5) Verify that the schedule matches the lights operated by the
relay.
6) Once the line circuits are connected and verified, connect low
voltage switch wiring to relays or devices.
Components 1.4
A-1.1,2,3,4 -Relays & Panels, HID
www.DouglasLightingControls.com

Technical
WR-4075, WR-4040
Transformers
CONNECTIONS
Lights
H
Breaker
Transformer
24VAC
W
B
Relays
Number of Relays
per Switch
White
Blue
Red
PART No.
WR-4075-
120/277
WR-4075-
120/347
WR-4075-240
Wire Length
One way measure
in feet (meters)
WR-4040-120
WIRE DISTANCE CHART - 18Ga Wire
120/277V Primary
: 24VAC* Secondary
120/347V Primary
: 24VAC* Secondary
240V Primary
: 24VAC* Secondary
One-way Measurement - feet (meters)
Wire Gauge
American
Wire Gauge
DESCRIPTION
The transformer supplies the
switching for Douglas 2-wire relay
control. 2-wire relays are latching
type and only require power to
switch on or off. One transformer is
sufficient to service many relays
and devices.
WR-4075 Series: Standard Duty
• 40VA steady draw, 75VA pulsed draw.
• Current limiting and internally fused with an
automatically resetting thermal fuse.
* Secondary voltage varies from
24V to 29V depending upon load.
WR-4040 Series: Light Duty
• 40VA steady draw, 40VA pulsed draw.
• Current limiting and internally fused with a one
time event fuse.
120V Primary : 24VAC Secondary
Sw
SPECIFICATION
Input
• Line voltage 120,240,277 or
347V. Select correct model fo
line voltage.
Output
• 24VAC at full load. At no or low
loads, the voltage is 29V. As the
current draw increases, the
transformer voltage decreases. A
fully loaded class 2 transformer
will output 24V.
• Douglas products are designed to
operate correctly over the entire
range of voltages provided by th
transformer.
Class 2 - Current Limiting
• Transformers that are approved
for powering Class 2 circuits are
current limited to prevent
excessive currents caused by
shorts. This is a key safety feature
to help prevent fires from shorts.
• The Class 2 current limiting
feature permits the use of wire
that is of a light gauge and has
less stringent insulation
requirements.
Environment
• Indoors, stationary, non-vibrating,
non-corrosive atmosphere and
non-condensing humidity.
• Ambient temperature:
-20°F to +120°F (-28°C to +50°C)
Approvals & Certifications
• UL Approved
• CSA Certified
DIMENSIONS & MOUNTING
Douglas transformers have a
nipple & mounting nut suited for a
7/8" hole (1/2" pipe hole & tread size)
3.15
WR-4075
Series
Transformers
1.5A & 3.0A rated switches
(WR-8001, WR-8501, WR-8503)
1
2
3
4
2000 (600)
1500 (450)
1000 (300)
500 (150)
18 AWG
18 AWG
18 AWG
18 AWG
2.56
2.38
6"wire
3.15
WR-4040
Series
Transformer
3.0 A rated switches
(WR-8001, WRK-8201)
6
8
300 (90)
160 (50)
18 AWG
18 AWG
2.00
6"wire
2.87
Components 2.1
A-2.1,2 -Relays & Panels, Transformers
www.DouglasLightingControls.com

Technical
WR-4075, WR-4040
Transformers
Lights
H
Breaker
Relay Panel Schematic
Transformer
24VAC
W
B
Relay
Relay Panel
Switching from
many Locations
Sw
Sw
Sw
TRANSFORMER LOADS
Douglas relays do not use any power while in the latched on or off
state. Power is only used when the relay switches over.
In the vast majority of cases, only 1 transformer per relay panel
will be all that is required. Theoretically, there is no limit to the
amount of relays that can be switched by 1 transformer.
There are Douglas devices other than relays that do use low
amounts of steady state power. For example, the LEDs of the LED
style switches use power. Relay scanners, time clocks, and other
electronic devices also use power. If a large number of these
devices are powered by one transformer, do a "LOADING
CALCULATION" to ensure that there is no overload. In the rare
case there is an overload, split the circuits and use more than 1
transformer.
Relays
Relay
Scanner
Electric current available for
switching relays and for losses
due to wiring lengths.
W B
Switching
Large Loads
Sw
Switching from
a Distance
Sw
Switching
Control Devices
(Group Switching)
Sw
Switching
Individual Loads
Sw
Sw
Transformer Loading Diagram
Steady loads are deducted from current limit to determine
momentary current available relay switching.
3000mA
1600 mA
700 mA
0 mA
Momentary
Switching
current limit
(75VA or 3000mA)
(WR-4075 series only)
Steady state
current limit
(40VA or 1600mA)
300mA 400mA
100 LED
Switches
2 Scanners &
1 Photocell
LOADING CALCULATIONS
If a large number of devices are being connected to a transformer,
check to ensure that the transformer loading is correct. The
example shown below illustrates the method of calculation.
EXAMPLE: A system has the following components.
100 LED switches
48 2-wire relays
2 Relay scanners
1 Photocell controller
Check how many relays can be switched at one time.
A) Calculate the maximum number of relays that can be switched
at one time ignoring wiring distance:
1) Total the steady state current requirement
Led Switches 100 x 4mA = 400mA
Relays 48 x 0mA = 0mA
Relay Scanners 2 x 100mA = 200mA
Photocell Controller 1 x 100mA = 100mA
700mA
2) Check that the steady state current requirement does not
exceed 1.6 Amperes. In the rare cases that the steady state
current exceeds 1.6 A, extra transformers will have to be
added and circuitry will have to be split.
For this example, the steady state current is 700mA which
is less than 1.6 amperes (1600mA).
3) Subtract the steady state current from the total momentary
current available to obtain the amount of current available
for switching relays.
Total current available form a WR-4075 series transformer
for a momentary switching pulse is 3000mA (75VA).
For this example, the current available for switching relays
is 2300mA (3000 - 700).
4) Divide the total available relay current by the current draw
of a relay (350mA) to obtain the maximum number of relays
that can be switched at one time.
2300 ÷ 350 = 6.57 - Round the answer down to 6 relays.
B) The maximum number of relays that can be switched at one
time is either the value obtained by the above calculation or
the value determined by the maximum wiring distance allowed
- WHICHEVER IS LESS.
If the wire distance is 600 feet and the wire gauge is #18 AWG,
then the limit is 4 relays, not 6 relays (see wire distance chart).
Components 2.2
A-2.1,2 -Relays & Panels, Transformers
www.DouglasLightingControls.com