Bender RCM420 Series Service manual

RCM420 Series
Digital Ground Fault Monitor / Ground Fault Relay
Grounded and High-Resistance Grounded AC Systems
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Technical Bulletin
NAE1042031 / 08.2013

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RCM420 Series Digital Ground Fault Monitor / Relay
for Grounded AC Systems
RCM420
Features
• Ground fault monitoring for AC grounded
systems
• True RMS value measurement (AC)
• External measuring current transformer
• Two separately adjustable response values
• Frequency range 42 - 2000 Hz
• 3 seperately adjustable time delays:
startup, response, and release
• Restart function
• LCD screen with real-time value display
• Latching or non-latching operating mode
• CT connection monitoring
• Power On LED, LED Alarm 1 / 2
• TEST / RESET button, internal / external
• Two separate voltage-free SPDT contacts
• Normally energized or de-energized
operation (selectable)
• Password protection
• Device self monitoring
• Sealable transparent cover
• Small form factor
• Conforms to RoHS
Approvals
Description
The RCM420 monitors for ground faults in grounded and high-resistance grounded AC
systems, both single- and three-phase. The RCM420 is specially designed to provide ad-
vanced warning of developing ground faults without the problems associated with high
sensitivity nuisance tripping.
A digital LCD screen displays real-time measurements of the system's ground fault cur-
rent. Two separately adjustable SPDT contacts allow for information transmission (such
as to a PLC) or power interruption (such as through a contactor or shunt trip breaker).
Since the values are measured with measuring current transformers, the device is nearly
independent of the load current and the nominal voltage of the system.
Applications
• Ground fault detection in single- or three-phase AC systems
• Motor and motor control systems
• Heat tracing systems
• Current monitoring of normally offline single conductors
• Alarm systems, safety devices
• HVAC systems
• Generators, portable and fixed
• Industrial controls
Function
Once the supply voltage USis applied,the starting delay ("t") activates. Alarms during this
delay will not cause the RCM420 to switch over the contacts.
Measurements of the system's ground fault current are taken via an external current trans-
former. All phases (including the neutral if one exists) are placed through the current trans-
former. The measured value is indicated in real-time on the device's LCD display.
If the measured value exceeds one or both response values, the respective response delays
ton1 / 2 activate. If the ground fault still exists after the response delays expire, the respec-
tive contacts switch over and the alarm LEDs activate. If the device is set to non-latching
mode and the ground fault clears, the alarms will clear after the set release time “toff” ex-
pires. If the device is set to latching mode, the alarms will not clear until the device is re-
set manually or the supply voltage is lost. The TEST function allows for an internal opera-
tion testing of the device. The device's easy-to-use onboard menu manages all settings via
the detailed LCD screen. An optional password protection setting protects unauthorized
users from changing settings.
Connection monitoring
The connections between the device and the external current transformer are continu-
ously monitored. If the device detects a connection error, the CT connection monitoring
alarm will activate, and the contacts will switch over without delay. After the connection
error is cleared, the device will reset based on its latching/non-latching setting.
Restart function
If an alarm is pending after resetting the alarm relay and restarting the system being moni-
tored, this reset process is repeated until the preset number of restart cycles is completed.
As soon as the preset number of restart cycles is completed, the fault memory is set to ON
(latching operation). A manual reset will be required.
Latching capability
The RCM420 has the capability to be set to latch on an alarm and require a manual reset, or
automatically reset when the fault has been cleared. Additionally, the "con" setting allows
for latching, and if a power loss to the RCM420 occurs, it will return to a latched state when
power is restored.
BENDER Inc. • 700 Fox Chase, Coatesville PA 19320 • Ph: 800-356-4266 / 610-383-9200 • Fax: [phone]

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Operating and display elements
1 - Power “ON” LED (green): Illuminates when power is received
to the unit. Flashes when the current transformer connection
alarm is active.
2 - Alarm LED “AL1” (yellow): Alarm 1, illuminates when the set
response value IΔn1 has been exceeded. Flashes when the
current transformer connection alarm is active.
3 - Alarm LED “AL2” (yellow): Alarm 2, illuminates when the set
response value IΔn2 has been exceeded. Flashes when the
current transformer connection alarm is active.
4 - Multi-functional LCD display
5 - TEST button: Activates self-test
Arrow up key: Scrolls up inside device's menu
6 - RESET button: Resets device
Arrow down key: Scrolls down inside device's menu
7 - MENU key: Activates device's internal menu
Enter key: Confirm change inside device's menu
Escape key (held > 1.5 s): Goes back a step inside menu
1
4
5
2 3
6 7
Load
GND
1 - External supply voltage used to power device
a 6 A fuse recommended for internal short circuit protection.
2 - Connection to external current transformer. All phases,
including the neutral if one exists, are placed through the
current transformer.
3 - Alarm relay K1: programmable for IΔn1 / IΔn2 / TEST / ERROR
4 - Alarm relay K2: programmable for IΔn1 / IΔn2 / TEST / ERROR
5 - Combined external TEST and RESET button
* - When shielded cabling is used.
Note: Do not route the ground conductor through the mea-
suring current transformer when also routing the power con-
ductors.
Wiring diagram
12
*
3
4
5

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Ground Fault Monitor RCM420
Insulation coordination acc. to IEC 60664-1 / IEC 60664-3
Rated insulation voltage 250 V
Rated impulse voltage / pollution degree 2.5 kV / III
Protective separation (reinforced insulation) between
(A1, A2) - (k / l, T / R) – (11, 12, 14) – (21, 22, 24)
Voltage test according to IEC 61010-1 2.21 kV
Supply voltage
Supply voltage USsee ordering details
Power consumption ≤ 3 VA
Measuring circuit
External measuring current transformer W - , WR - , WS - series
Load 68 Ω
Rated insulation voltage (measuring current transformer) 800 V
Operating characteristic acc. to IEC 62020 Type A
Rated frequency 42 - 2000 Hz
Measuring range 3 mA - 16 A
Relative percentage error 0 - - 20 %
Display accuracy ± 15 %
Response values
Rated residual operating current IΔn1 (prewarning) 50 - 100 % x IΔn2 (50 %)*
Rated resiudal operating current IΔn2 (alarm) 10 mA - 10 A (30 mA)*
Hysteresis 10 - 25 % (15 %)*
Specified time
Starting delay t 0 - 10 s (0,5 s)*
Response delay ton2 (alarm) 0 - 10 s (0 s)*
Response delay ton1 (prewarning) 0 - 10 s (1 s)*
Delay on release toff 0 - 99 s (1 s)*
Operating time tae at IΔn = 1 x IΔn1 / 2 ≤ 180 ms
Operating time tae at IΔn = 5 x IΔn1 / 2 ≤ 30 ms
Response time tan tan = tae + ton1 / 2
Recovery time tb≤ 300 ms
Number of restart cycles 0 - 100 (0)*
Cable lengths for current transformers
Single wire ≥ AWG 20 (0.75 mm2)0 . . . 3.2 ft (0 - 1 m)
Single wire, twisted ≥ AWG 20 (0.75 mm2)0 . . . 32.8 ft (0 - 10 m)
Shielded cable ≥ AWG 22 (0.5 mm2)0 . . . 131 ft (0 - 40 m)
Recommended cable (shielded, shield on one side connected
to terminal l of the RCM420, not connected to earth) J-Y(ST)Y min. 2 x 0.8
Connection screw terminals
Displays, memory
Display range, measuring value 3 mA - 16 A
Relative percentage error 0 - - 30 % / ± 2 digit
Measured-value memory for alarm value data record measured values
Password off / 0 - 999 (off)*
Latching behavior
ON / OFF / CON (Latching / Non-latching / Remains latched on return from power loss)
Inputs / outputs
Cable length for external test / reset button 0 - 32 ft (0 - 10 m)
Switching elements
Number of switching elements 2 SPDT contacts
Operating principle normally energized or normally deenergized(*)
Electrical service life under rated operating conditions 10.000 switching operations
Contact data acc. to IEC 60947-5-1
Utilization category AC-13 AC-14 DC-12 DC-12 DC-12
Rated operational voltage 230 V 30 V 24 V 110 V 220 V
Rated operational current 5 A 3 A 1 A 0.2 A 0.1 A
Minimum contact load 1 mA at AC / DC ≥ 10 V
Environment / EMC
EMC IEC 62020: 2003-11
Operating temperature - 25 °C - + 55 °C
Climatic class acc. to IEC 60721
Stationary use (IEC 60721-3-3) 3K5 (except condensation and formation of ice)
Transport (IEC 60721-3-2) 2K3 (except condensation and formation of ice)
Long-time storage (IEC 60721-3-1) 1K4 (except condensation and formation of ice)
Classification of mechanical conditions IEC 60721
Stationary use (IEC 60721-3-3) 3M4
Transport (IEC 60721-3-2) 2M2
Long-time storage (IEC 60721-3-1) 1M3
Connection
Connection screw terminals
rigid / flexible AWG 24 - 12 / 24 - 14
Multi-conductor connection (2 conductors with the same cross section)
rigid / flexible AWG 24 - 14 / 24 - 14
Stripping length 8 - 9 mm
Tightening torque 0.5 - 0.6 Nm
Other
Operating mode continuous operation
Position of normal use any
Degree of protection, internal components (IEC 60529) IP30, NEMA 1
Degree of protection, terminals (IEC 60529) IP20, NEMA 1
Enclosure material polycarbonate
Flammability class UL94V-0
DIN rail mounting acc. to IEC 60715
Screw mounting 2 x M4 with mounting clip
Standards IEC 62020
Instruction leaflet TGH1410
Weight ≤ 150 g
( )* factory setting
Technical data

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Dimensions
Dimensions in inches (mm)
1.42” (36)
2.78”
(70.5)
1.87”
(47.5)
1.22” (31.1)
2.66” (67.5)
1.77” (45)
3.54” (90)
Supply voltage 1) USOutputs Type Ordering No.
DC AC
9.6 - 94 V 16 - 72 V (15 - 460 Hz) 2 SPDT contacts RCM420-D-1 B 9401 4001
70 - 300 V 70 - 300 V (15 - 460 Hz) 2 SPDT contacts RCM420-D-2 B 9401 4002
Ordering Information
Description Ordering No.
Mounting clip for screw mounting
(1 piece per device) B 9806 0008
Accessories Compatible Current Transformers
CT Type Opening Size
in inches (mm) Part No. Ordering No.
circular,
closed
1.35" (35) W1-S35 B 911 731
2.75" (70) W2-S70 B 911 732
4.1" (105) W3-S105 B 911 733
5.5" (140) W4-S140 B 911 734
8.25" (210) W5-S210 B 911 735
rectangular,
closed
2.75" X 6.9" (70 x 175) WR70X175S B 911 738
4.5" x 12" (115 x 305) WR115X305S B 911 739
5.9" x 13.8" (150 x 350) WR150X350S B 911 740
rectangular,
split-core
2" x 3.1" (50 x 80) WS50X80S B 911 741
3.1" x 3.1" (80 x 80) WS80X80S B 911 742
3.1" x 4.7" (80 x 120) WS80X120S B 911 743
exible,
open type*
6.7" (170)* WF170-2 B 9808 0201
9.8" (250)* WF250-2 B 9808 0203
19.7" (500)* WF500-2 B 9808 0205
31.5" (800)* WF800-2 B 9808 0207
47.2" (1200)* WF1200-2 B 9808 0209
Notes on WF series flexible current transformers:
• The listed dimension is the length of the flexible cable, not
the opening size when closed. Closed circumference must be
calculated appropriately.
• WF series current transformers additionally utilize the
RCC420 signal converter, which requires supply voltage. See
WF series datasheet for more information.
• When WF series current transformers are used with the
RCM420, CT connection monitoring must be disabled. Refer
to RCM420 manual for more information.

Document NAE1042031 / 08.2013 / © Bender Inc.
T M
Canada • Mississauga, ON
Toll-Free: 800-243-2438 • Main: 905-602-9990
Fax: [phone] • E-mail: [email protected]
USA • Coatesville, PA
Toll-Free: 800-356-4266 • Main: 610-383-9200
Fax: [phone] • E-mail: [email protected]
bender.org • bender.org/mobile