Littelfuse D0920 User manual

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Arc-Detection Unit
D0920
D0920
ARC-DETECTION UNIT
REVISION 0-D-070616
Document Number: PM-1410-EN

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TABLE OF CONTENTS
1 INTRODUCTION............................................................................................................. 5
1.1 General....................................................................................................................... 5
1.2 A0220 Point Sensor................................................................................................... 5
2 OPERATION ................................................................................................................... 6
2.1 Front-Panel Controls and Indication.......................................................................... 6
2.1.1 Sensor Adjust......................................................................................................... 6
2.1.2 ACTIVE and TEST Mode....................................................................................... 6
2.1.3 Power..................................................................................................................... 6
2.1.4 Tripped................................................................................................................... 6
2.2 Auxiliary Relays ......................................................................................................... 6
2.2.1 Trip Indication ........................................................................................................ 6
2.2.2 Remote Signalling.................................................................................................. 6
3 INSTALLATION............................................................................................................... 9
3.1 D0920 Arc-Detection Unit.......................................................................................... 9
3.2 A0220 Point Sensor................................................................................................... 9
4 TECHNICAL SPECIFICATIONS................................................................................... 12
4.1 D0920....................................................................................................................... 12
4.2 A0220 Point Sensor................................................................................................. 14
5. ORDERING INFORMATION......................................................................................... 15
6. WARRANTY.................................................................................................................. 15
7. PERFORMANCE TEST................................................................................................ 15
APPENDIX A D0920 REVISION HISTORY....................................................................... 17
LIST OF FIGURES
1 D0920 Arc Detection Unit .............................................................................................. 5
2 A0220 Point Sensor....................................................................................................... 5
3 D0920 Outline and Mounting Details............................................................................. 7
4 D0920 Typical Wiring Diagram...................................................................................... 8
5 A0220 Outline and Connections.................................................................................. 10
6 A0220 Mounting Details............................................................................................... 11
7 A0220 Detection Range for a 3 kA Fault..................................................................... 11
LIST OF TABLES
1 Test Record.................................................................................................................. 16

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1 INTRODUCTION
1.1 General
The D0920 Arc Detection Unit is a high-speed arc-detection device for electrical power-distribution
systems. The D0920 requires a 230 Vac supply and supports up to three point sensors (A0220)
mounted in a switchboard.
On the occurrence of an arc fault, the D0920 detects the fault and pulses the trip output in less
than 1 ms. The fast trip time reduces the risk of personal injury and equipment damage.
The D0920 is typically supplied from the switchboard main power. The AC voltage may fail when
an arc fault develops. The D0920 uses energy stored in an internal capacitor to trip the circuit
breaker. The storage capacitor is an extremely long-life electrolytic capacitor with a specified life
time of more than 30 years at an ambient temperature of 50°C (121°F). The trip energy stored is
sufficient for circuit breakers with a 220/250 Vdc shunt trip coil.
The D0920 has one output indication relay with an isolated normally-open contact, and one output
indication relay with an isolated normally-closed contact. Additional features include power and
trip indication, test mode, and sensitivity adjustment.
NOTE: Dangerous voltage is present at the storage capacitor (terminals 4, 7, and 8) even after the
relay has been disconnected from the supply voltage. The capacitor has a self-discharge circuit
which will discharge it to a safe voltage level within two minutes after disconnection from the
supply voltage.
1.2 A0220 Point Sensor
The A0220 point sensor is a photoelectric sensor with a sensitivity range of 180 degrees. It has a
transparent polycarbonate enclosure that is IP65 rated. Each point sensor includes 10 m (33 ft) of
shielded 2-wire, 24 AWG (0.2 mm2) cable. The cable length can be extended to a maximum of
50 m (164 ft), however use shielded 2-wire, 20 AWG (0.5 mm2) cable.
FIGURE 1. D0920 Arc Detection Unit.
FIGURE 2. A0220 Point Sensor.

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2. OPERATION
2.1 Front-Panel Controls and Indication
2.1.1 Sensor Adjust
The D0920 sensitivity default is 6 mA of sensor output current to cause a trip. This is equivalent to
a light intensity of 12,000 lux on a single sensor or 6,000 lux on each of two sensors. This means
that the total light intensity on all sensors installed has to exceed 12,000 lux to cause a trip.
The sensitivity is adjustable from 1 to 12 mA (2,000 to 24,000 lux) using the SENSOR ADJUST
dial.
2.1.2 ACTIVE and TEST Mode
The D0920 has a two-position switch, marked ACTIVE and TEST.
The green LED labelled ACTIVE indicates that the ACTIVE mode has been selected. In the
ACTIVE mode, the D0920 is configured for normal operation and will trip the trip coil if an arc flash
occurs. In ACTIVE mode, the relay K2 contact (terminals 11 and 12) will be open unless supply
voltage is removed. Ensure that the D0920 is normally set to the ACTIVE mode.
The red LED labelled TEST indicates that the TEST mode has been selected. In the TEST mode,
the D0920 and any connected point sensors can be tested without tripping the trip coil. In TEST
mode, relay K2 will be closed. See Fig. 4.
2.1.3 Power
The green LED labelled POWER indicates the presence of supply voltage.
2.1.4 Tripped
The red LED labelled TRIPPED indicates a trip.
A trip remains latched until the RESET button is pressed. External circuit breakers or other
devices will have to be reset manually.
2.2 Auxiliary Relays
2.2.1 Trip Indication
The D0920 has one normally-open contact (K1, terminals 9 and 10) that closes during a trip. It can
be used for trip indication.
2.2.2 Remote Signalling
The D0920 has one normally-closed contact (K2, terminals 11 and 12) that closes during loss of
supply, or when the D0920 is in the TEST mode. It can be used for remote signalling.

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FIGURE 3. D0920 Outline and Mounting Details.

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FIGURE 4. D0920 Typical Wiring Diagram.
POINT
SENSORS
12 3
RED
GREEN
SHIELD
9
10
11
12
K1
K2
NOTE 2
NOTE 3
TRIP
INDICATION
TEST AND
LOSS OF
SUPPLY
ABC
230 VAC
56
L1 L2/N
4
7
8
NOTE 1
NOTE 1
NOTE 1
TRIP
COIL
EXTERNAL
TRIP
TRIP COIL
(+)
TRIP COIL/
NEUTRAL
D0920
SENSOR SHIELD
NOTES:
1. CAUTION: DANGEROUS VOLTAGE IS PRESENT AT TERMINALS 4,7, AND 8, SOURCED FROM AN INTERNAL STORAGE CAPACITOR. A SELF-
DISCHARGE CIRCUIT WILL DISCHARGE THE STORAGE CAPACITORTO A SAFE LEVEL WITHIN TWO MINUTES AFTERTHE AC SUPPLY HAS
BEEN DISCONNECTED.
2. RELAY CONTACT IS SHOWN DE-ENERGIZED.
3. RELAY CONTACT IS CLOSED WHEN TEST MODE IS SELECTED, OR DURING LOSS OF SUPPLY.

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3 INSTALLATION
3.1 D0920 Arc-Detection Unit
Outline and connection details are shown in Fig. 3. The D0920 can be DIN-rail mounted only. A
typical wiring diagram is shown in Fig. 4.
Connect supply voltage to terminals 5 (L1) and 6 (L2/N). The nominal supply voltage is 230 Vac.
Connect the 230/250 Vdc trip coil from a circuit breaker to terminals 7 (TRIP COIL +) and 8 (TRIP
COIL NEUTRAL). The trip coil output is not isolated from the 230 Vac supply input. To initiate an
external trip, install a normally-open momentary (250-Vac-rated) switch between terminals 4
(EXTERNAL TRIP) and 7 (TRIP COIL +). Limit the time the switch is closed to one second.
Do not install modules or sensors which have been damaged in transport.
NOTE: Dangerous voltage is present at the storage capacitor (terminals 4, 7, and 8) even after the
relay has been disconnected from the supply voltage. The capacitor has a self-discharge circuit
which will discharge it to a safe voltage level within two minutes after disconnection from the
supply voltage.
3.2 A0220 Point Sensor
Outline and connection details are shown in Fig. 5. Connect the red wire to terminal 1, the green
wire to terminal 2, and the shield to terminal 3. If more than one sensor is connected, do not mix
wire colors. Each sensor has an adhesive-backed drill template for surface-mount installation.
Place the drill template where the sensor is to be mounted. See Fig. 6.

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FIGURE 5. A0220 Outline and Connections.