Specifications are subject to change without notice (09.12.05) 1
Monitoring Relays
3-Phase Load Guard
Types DWB01, PWB01
•TRMS load guard relays for three phase
balanced applications
•Measuring if the power factor is within set limits
•Measure voltage on own power supply
•Measuring ranges: 5A, 10A, MI current transformers
•Power ON delay 1 to 30 s knob adjustable
•Separately adjustable upper/lower level on absolute
scale
•Programmable latching or inhibit at set level
•Automatic and manual start and stop of the system
•Output: 8 A SPDT relay N.D. or N.E. selectable
•For mounting on DIN-rail in accordance with DIN/EN
50 022 (DWB01) or plug-in module (PWB01)
•45 mm Euronorm housing (DWB01) or 36 mm plug-in
module (PWB01)
•LED indication for relay, alarm and power supply ON
Product Description
DWB01 and PWB01 are
precise TRMS power factor
monitoring relays for 3-
phase balanced systems.
They can be used for moni-
toring the actual load of
asynchronous motors and
other symmetrical loads,
wherethe power factor is
almost proportional to the
load.
The relay measures the
power factor (cos ϕ), that is
the ratio between the active
and the apparent power of a
motor.
Start/stop input allows to
use a manual switch to start
and stop the motor, without
the need of an auxiliary
device.
The advantage of using the
latch function is that the
relay can be kept energized
even after the end of the
alarm condition. Inhibit func-
tion can be used to avoid
relay operation when not
desired (maintenance, tran-
sients).
The LED's indicate the state
of the alarmand the output
relay.
Type Selection
Mounting Output Supply: Supply: Supply: Supply:
208 to 240 VAC 380 to 415 VAC 380 to 480 VAC 600 to 690 VAC
DIN-rail SPDT DWB 01 C M23 10A DWB 01 C M48 10A DWB01 C M69 10A
Plug-in SPDT PWB 01 C M23 10A PWB 01 C M48 10A
Input Specifications
Input
Voltage (Own power supply):
3-phase DWB01: L1, L2, L3
PWB01: 5, 6, 7
M23: 208 to 240 VAC ± 15%
DWB01CM48: 380 to 480 VAC ± 15%
PWB01CM48: 380 to 415 VAC ± 15%
DWB01CM69: 600 to 690 VAC ± 15%
1- phase DWB01CM23: L1, L2 (connect pins L2, L3)
PWB01CM23:5, 6 (connect pins 6, 7)
208 to 240 VAC ± 15%
Current: DWB01: 5A, 10A: I1, I2
MI...: U1, U2
PWB01: 5A, 10A: 11, 10
MI...: 9, 8
Measuring ranges Upper level Lower level
Power factor (cos ϕ) 0.1 to 0.99 0.1 to 0.99
AACrms Max. curr.
(30 s)
Direct input: 0.5 to 5A 30A
1to 10A 50A
StandardCT (examples)
TADK2 50 A/5 A 5 to 50 A 60 A
TAD2 150 A/5 A 15 to 150 A 180 A
TAD6 400 A/5 A 40 to 400 A 480 A
TAD12 1000 A/5 A 100 to 1000 A 1200 A
TACO200 6000 A/5 A 600 to 6000 A 7200 A
MI CT ranges
MI 100 10 to 100 A 325 AAC
MI 500 50 to 500 A 1000 AAC
DWB01 PWB01
Ordering key
Housing
Function
Type
Item number
Output
Power Supply
Range
DWB 01 C M48 10A
2Specifications are subject to change without notice (09.12.05)
DWB01, PWB01
Supply Specifications
General Specifications
Power supply Overvoltage cat. III
Rated operational voltage (IEC 60664, IEC 60038)
Through terminals:
DWB01: L1, L2, L3
PWB01: 5, 6, 7
M23 177 to 276 VAC 45 to 65 Hz
DWB01CM48 323 to 552 VAC45 to 65 Hz
PWB01CM48 323 to 477 VAC 45 to 65 Hz
DWB01CM69 510 to 793 VAC 45 to 65 Hz
Dielectric voltage None
Dielectric voltage
supply to output 4kV
Rated operational power
M23: 9 VA @ 230 VAC, 50 Hz
M48: 13 VA @ 400 VAC, 50 Hz
M69: 21 VA @ 600 VAC, 50 Hz
Supplied by L1 and L2
Power ON delay 1to 30 s ± 0.5 s
Reaction time (input signal variation from
-20% to +20% or from
+20% to -20% of set value)
AlarmON delay <200 ms
Alarm OFF delay < 200 ms
Accuracy (15 min warm-up time)
Temperature drift ± 1000 ppm/°C
Delay ON alarm ± 10% on set value ± 50 ms
Repeatability ± 0.5% on full-scale
Indication for
Power supply ON LED, green
AlarmON LED, red (flashing 2 Hz
during delay time)
Output relay ON LED, yellow
Environment
Degree of protection IP 20
Pollution degree 3(DWB01), 2 (PWB01)
Operating temperature
@Max. voltage, 50 Hz -20 to 60°C, R.H. < 95%
@Max. voltage, 60 Hz -20 to 50°C, R.H. < 95%
Storage temperature -30 to 80°C, R.H. < 95%
Housing dimensions
DIN-rail version 45 x 80 x 99.5 mm
Plug-in version 36 x 80 x 94 mm
Weight Approx. 250 g
Screw terminals
Tightening torque Max. 0.5 Nm
acc. to IEC 60947
Approvals UL, CSA
CE-Marking Yes
EMC Electromagnetic Compatibility
Immunity According to EN 61000-6-2
Emissions According to EN 61000-6-3
Output Specifications
Output SPDT relay
Rated insulation voltage 250 VAC
Contact ratings (AgSnO2)µ
Resistive loads AC 1 8 A @ 250 VAC
DC 12 5 A @ 24 VDC
Small inductive loads AC 15 2.5 A @ 250 VAC
DC 13 2.5 A @ 24 VDC
Mechanical life ≥30 x 106operations
Electrical life ≥105operations
(at 8 A, 250 V, cos ϕ=1)
Operating frequency ≤7200 operations/h
Dielectric strength According to EN 60947-1
Dielectric voltage ≥2kVAC (RMS)
Rated impulse withstand volt. 4 kV (1.2/50 µs)
Input Specifications (cont.)
Note:
The input voltage cannot
raise over 300 VAC with
respect to ground (PWB01
only)
Contact input
DWB01 Terminals Z1, U1
PWB01 Terminals 2, 9
Disabled > 10 kΩ
Enabled < 500 Ω
Pulse width > 500 ms
Hysteresis PF approx 0.1
Mode of Operation
DWB01 and PWB01 can be
used for monitoring the actu-
al load of asynchronous
motors.
The relay measures the
absolute value for the power
factor of the system PF=
Active Power/Apparent Pow-
er that is for balanced sys-
tem with sinus waveforms
the cosine of the angle
between motor current and
motor voltage (cos ϕ).
As cos ϕvaries with the load
of the motor, underload and
overload can be indirectly
detected by DWB01 and
PWB01.
The relation between the
load and cos ϕdepends on
the type of motor.As a
guideline to ensure correct
working conditions for a
motor, the upper level could
be set above the cos ϕ
marking on the motor,and
the lower level under this val-
ue. It is anyway recommend-
ed to make the adjustment in
connection with a practical
test. The relay has an
adjustable power ON delay
in order to avoid overload
detection during motor start.
Example 1
Latching mode, relay NE
In this application DWB01 or
PWB01 areconnected to an
external current metering
transformer, type MI..., (con-
nected between U1 & U2) as
Specifications are subject to change without notice (09.12.05) 3
Select the desired function
setting the DIP-switches 1
to 4 as shown on the right.
Toaccess the DIP-switches
open the plastic cover using
ascrewdriver as shown on
the right.
If DIP switch 3 is set to ON
(start/stop) the position of
DIP-switch 4 does not affect
the products working mode.
Centre knobs:
Setting of upper and lower
level of cos ϕ0.1 to 0.99.
Lower left knob:
Setting of delay on absolute
scale: 0.1 to 30 s.
Lower right knob:
Setting of power ON delay
on absolute scale: 1 to 30 s.
DWB01, PWB01
Function/Range/Level/Time Setting
Working mode
ON: Contact input for start/stop functions
OFF: Contact input for latch/inhibit functions
Relay status
ON: Relay de-energized in normal condition
OFF: Relay energized in normal condition
Input current range (terminals I1, I2 or 10, 11)
ON: 10A
OFF: 5A/MI input
Contact input (SW4 does not affect the
working mode if SW3 is ON)
ON: Latch function enable
OFF: Inhibit function enable
Mode of Operation (cont.)
well as to a 3-phase asyn-
chronous motor. The relay
energizes as soon as the
power supply is applied.
After the power ON delay,
the unit starts measuring cos
ϕ.If cos ϕis within the set-
points the relay is energized.
As soon as the power factor
drops below the lower set-
point or exceeds the upper
setpoint the output relay
releases and the red LED
turns on after the set time
has expired. To restart the
cos ϕmeasurement, connect
Z1 and U1 (2 and 9) or inter-
rupt the power supply for at
least 1 s.
Example 2
Non-latching mode, relay NE
DWB01 and PWB01 react as
described in the previous
example 1 except for the
automatic reactivation of the
relay as soon as cos ϕis
back within the two set-
points. When the measured
cos ϕexceeds the set upper
level, the red LED starts
flashing. The output relay
releases after the set time
period. When the measured
cos ϕdrops below the set
lower level, the red LED
starts flashing, and the out-
put relay releases after the
set time period. When the
output relay releases there
will be no LED indication.
Example 3
1-Phase load monitoring
DWB01CM2310A and
PWB01CM2310A can be
used for monitoring the pow-
er factor of a 1-Phase load
with 208 to 240 V AC mains
voltage. In this case the pow-
ersupply has to be connect-
edbetween L1, L2 (or 5, 6),
L2and L3 (or 6 and 7) have
to be connected.
Example 4
Start/stop mode, relay NE
In this application DWB01 or
PWB01 are directly connect-
edto a 3-phase asyn-
chronous motor. The relay
energizes as soon as the
power supply is applied and
the start/stop contact is
closed. After the power ON
delay, the unit starts measur-
ing cos ϕ.If cos ϕis within
the setpoints the relay ener-
gizes. As soon as the power
factor drops below the lower
setpoint or exceeds the
upper setpoint the output
relay releases and the red
LED turns ON after the set
time has expired. When the
start/stop contact is opened
the relay de-energizes imme-
diately. To restart the system
just connect the start/stop
contact.
Note 1: to use the start/stop
function the output relay has
tocommand a contactor
connected in series to the
load (see last two wiring dia-
grams).
Note 2: in case of current
below the minimum level the
alarm is conventionally ON.
Note 3: (3-phase voltage):
connect the 3-phase power
supply to the terminals L1,
L2 and L3 (DWB01) - 5, 6
and 7 (PWB01) taking care of
the sequence.
Contact input working mode
CLOSED OPEN
LATCH NOT ACTIVE ACTIVE
INHIBIT ACTIVE NOT ACTIVE
START/STOP START STOP
L2 L3L1
15
16 18
cos j
cos j
U1
U2
Z1
I2I1
Contact input
DWB01
675
1
43
cos j
cos j
9
8
2
1011
Contact input
PWB01
Notes
1.DIP-switch 3 set ON enables the start/stop
function that is managed by the closing-
opening of the contact input.
2.DIP-switch 3 set OFF enables the input
contact for the latch/inhibit functions: the
selection between these is allows by the DIP
switch 4.
The following table shows how the input con-
tact manages the mode of operation:
4Specifications are subject to change without notice (09.12.05)
DWB01, PWB01
L2 L3L1
N
L
m
15
16 18
U1
U2
Z1
I2I1
cos j
cos j
675
N
L
m
1
43
9
8
2
1011
cos j
cos j
PWB01CM2310A - Direct connection - 1-Phase LoadDWB01CM2310A - Direct connection - 1-Phase Load
L2 L3L1
L1
L2
L3
m
15
16 18
Grey U1
U2
Z1
I2I1
cos j
cos j
675
L1
L2
L3
m
1
43
Grey 9
8
2
1011
cos j
cos j
DWB01 - MI CT PWB01 - MI CT
L2L3L1
L1
L2
L3
m
15
1618
U1
U2
Z1
I2I1
cos j
cos j
I1
675
L1
L2
L3
m
1
43
9
8
2
1011
cos j
cos j
I1
DWB01 - Standard CT PWB01 - Standard CT
Wiring Diagrams
L2 L3L1
L1
L2
L3
m
15
16 18
I1
cos j
cos j
U1
U2
Z1
I2I1
675
L1
L2
L3
m
1
43
I1
cos j
cos j
9
8
2
1011
DWB01 - Direct connection PWB01 - Direct connection
Latch/Inhibit
Contact
Latch/Inhibit
Contact
Latch/Inhibit
Contact
Latch/Inhibit
Contact
Latch/Inhibit
Contact
Latch/Inhibit
Contact
Latch/Inhibit
Contact
Latch/Inhibit
Contact
Specifications are subject to change without notice (09.12.05) 5
Operation Diagrams
T T T
Latch function - NE relay
Inhibit function - ND relay
L2L3L1
m
15
1618
L1
L2
L3
cos j
cos j
U1
U2
Z1
I2I1
I1
N
675
m
1
43
L1
L2
L3
cos j
cos j
9
8
2
1011
I1
N
PWB01 - Direct connection - Manual start and stop (NE relay)
DWB01 - Direct connection - Manual start and stop (NE relay)
DWB01, PWB01
Wiring Diagrams (cont.)
Start/stop
Contact
Power supply
Latch contact
(Closed = latch not active)
Upper Level
Hysteresys
Hysteresys
Power
ON Power
ON
Lower Level
Relay ON
Power supply
Inhibit contact
(Closed = inhibit active)
Upper Level
Hysteresys
Hysteresys
Power
ON Power
ON
Lower Level
Relay ON
Start/stop
Contact
With the start/stop function enabled, it’s necessary to use the following wiring diagrams (which are two examples among
many others). It is possible for both 3-phase loads and 1-phase loads, either through direct connection or external current
metering transformer.
T T
Start and stop function - NE relay
Power supply
Start/Stop contact
(Closed = Start; Open = Stop)
Upper Level
Hysteresys
Hysteresys
Power
ON
Lower Level
Relay ON
6Specifications are subject to change without notice (09.12.05)
DWB01, PWB01
45
80
83.5
99.5
63
28.5
36
80
94
28.5
63
90
Plug-inDIN-rail
Dimensions
