MAKING MODERN LIVING POSSIBLE
Instruction
VLT® FC Series Drives Leakage Current Monitor Module
RCMB20/RCMB35
1.1
VLT® Leakage Current Monitor Module
VLT® Leakage Current Monitor Module
1 1
1.1.1 Intended Use
The AC/DC sensitive leakage current monitoring modules
RCMB20-500-01 and RCMB35-500-01 are used for fault
current monitoring in applications, where frequency
converters are used, and direct and/or alternating fault
currents are likely to occur.
Each module has to be installed and connected in the
cable connection compartment in front of the mains input
of the frequency converter.
Both variants of the modules provide an output signal
4...20 mA proportional to the high frequency leakage
current.
Warning
1.1.2
Only intended for use to protect equipment and not for
personal protection.
Table 1.1 Approval
Device Features
1.1.3
1.1.4
Functional Description
After switching the supply voltage on, the multi-colour LED
shows a green light and the leakage current monitoring
module carries out a self test.
The leakage current monitoring module measures both AC
and DC currents. The r.m.s. value is calculated by summing
up the DC components included in the leakage current
and the AC components that are below 500 Hz. A current
signal of 4…20 mA proportional to the rms value is
provided at the module output. The analogue value is
updated at the latest every 20 ms.
Every two seconds, the leakage current monitoring module
cyclically tests the connection to the measuring current
transformer and the correct functioning of the AC and DC
measurement. In addition, the supply voltage is monitored
continuously. If a fault occurs, the multi-colour LED flashes
red and the analogue DC output current is 20 mA.
LED Indication of Operation Status
1.1.5
LED continuously lights green = normal operating
condition
LED flashes red = fault
Examples of possible faults:
connection fault, current transformer fault, module fault
etc.
AC/DC sensitive measured value acquisition
•
Frequency range 0…500 Hz
•
Measuring current transformer, inside diameter 20
•
mm/35 mm
Measuring range 500 mA
•
Measuring time ≤ 180 ms
•
Supply voltage 24 V DC
•
Analogue output current 4…20 mA
•
CT connection monitoring using cyclical test
•
current
LEDs: power On LED, alarm LED
•
MI38U302 - VLT® is a registered Danfoss trademark 1
RCMB20/RCMB35
VLT® Leakage Current Monitor Module
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1.1.6 Installation and Connection
WARNING
Ensure safe isolation from supply in the installation area.
Observe the installation rules for live working. Failure to
observe the rules may result in physical injury and damage
to property.
Illustration 1.3 Installation Example 3, Enclosure B4
Illustration 1.1 Installation Example 1, Enclosure A2 and A3
Illustration 1.2 Installation Example 2, Enclosure B3
Illustration 1.4 Installation Example 4, Enclosure C3
2 MI38U302 - VLT® is a registered Danfoss trademark
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1
2
2
3
3
4
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RCMB20/RCMB35
VLT® Leakage Current Monitor Module
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Illustration 1.7 Screw Mounting with Mounting Brackets
(diagonal)
Type A B C D
Sensor RCMB20 47 29 63 20.35
Sensor RCMB35 47 48.5 63 12.85
Illustration 1.5 Dimension Diagram
Type A B C D E F G H
Sensor RCMB20 30 56.3 50 76.4 48.5 ø 20 29.8 16.4
Sensor RCMB35 30 79.2 62 99.5 55 ø 35 41.7 20
Table 1.2 Legend to Illustration 1.5
All dimensions are in mm!
Table 1.3 Legend to Illustration 1.7
Illustration 1.8 Position of the Terminals
Control terminal connectors can be unplugged from the
RCWB for ease of installation
Illustration 1.9 Conductor Connection
Illustration 1.6 Fitting the RCMB on the Mounting Plate
MI38U302 - VLT® is a registered Danfoss trademark 3
1. Insert the bared control wire into the contact.
2. Ensure the contact is firmly established and not
loose. Loose control wiring can be a source of
equipment faults or not optimal operation.
Illustration 1.10 Conductor Disconnection
Open the contact by inserting a small screwdriver into the
slot above the contact, as shown in Illustration 1.10.
M
Ia 4-20mA
L1
L2
L3
PE
20
12
B1 (+)
A1 (-)
A4 (-)
A3 (+)
55 (-)
53 (+)
RCMB
FC 300
+ 24 V DC
GND
IT/
High-Z/
TN/TT
Mains
Relay 1
1
0
Analog
Output
Bender
4,2 mA
4 mA
….
….
….
20 mA
RCMB20/RCMB35
VLT® Leakage Current Monitor Module
11
1.1.8 Application Example
The following example shows a typical application for the
use of the VLT® Leakage Current Monitor Module. Follow
Illustration 1.11 Wiring the Plug-in Terminal XK1
Terminal (pin assignment) Colour Sensor
a (A1) black
b (A2) - c (A3) white DC 4...20 mA
d (A4) blue GND (DC 4...20 mA)
e (B1) red
f (B2) - g (B3) - h (B4) - -
GND (US)
+24 V (US)
the installation description as shown in this Installation
Guide.
The following electrical connections are required: 24 V DC
voltage supply of the frequency converter from terminal 12
(+24 V DC) and 20 (common) to terminals B1 and A1 of
the monitoring device.
The analog signal (4-20 mA, A3(+) and A4(-)) of the
monitoring device has to be connected to terminals 53 (+)
and 55(-) to the frequency converter as well as the switch
S201 on the control card selected to „I“. After the entire
application is set to run mode with no faulty residual
currents, the monitoring device’s output is 4mA. An
Table 1.4 Legend to Illustration 1.11
existing earth fault current leads to an increased output
signal, proportional to the value of the fault current. Use
Wiring diagram
Connect the leakage current monitoring module according
to the wiring diagram. The output current in proportion to
the leakage current IA must be made available to the
frequency converter.
the Smart Logic control functions to define a set point for
achieving an alert on time. The example shown here uses
the potential free relay 1 of the frequency converter, to
report the status change to the upper level control system.
A bus system can be used instead or simultaneously.
Illustration 1.12 Wiring Diagram
Commissioning
1.1.7
CAUTION
Before commissioning, ensure that the RCM is properly
connected. A minimum distance of 25 mm between the
primary conductor and the control cable has to be
permanently assured.
Functional description
If the application is operating in good conditions, the
analog input of the frequency converter receives 4 mA out
of the monitoring device. If a threshold of 4.2 mA is
exceeded, a warning signal should be provided by the
frequency converter’s potential free relay 1. To dampen
short time effects, the switching of the relay may be
delayed by 1 second. With this approach, the existing of a
very low level ground earth fault will be alerted. The
threshold should be set close to the advised value, but can
be specified by the user in its entirety.
NOTE
Danfoss can under no circumstance give an advice, how
the signal shall be used, as each application has its specific
requirements. This can vary from just visualizing to cut off.
The required reaction has to be defined by the user.
Illustration 1.13 Relay Output
4 MI38U302 - VLT® is a registered Danfoss trademark
RCMB20/RCMB35
VLT® Leakage Current Monitor Module
Programming examples
The Smart Logic Control provides a comparator for the threshold, see Table 1.5.
ID Name Setup 1 Setup 2 Setup 3 Setup 4 Default value Unit
1310.0 Comparator Operand Analog input 53 Analog input 53 Analog input 53 Analog input 53 Disabled
ID Name Setup 1 Setup 2 Setup 3 Setup 4 Default value Unit
1311.0 Comparator Operator > > > > ≈ equal
ID Name Setup 1 Setup 2 Setup 3 Setup 4 Default value Unit
1312.0 Comparator Value 21 21 21 21 0.000
Table 1.5 Comparator for Threshold
The comparator value is calculated by: 1312.0 = I
[mA * 5 // 21,000 for 4.2 mA]
limit
The relay is linked to comparator 0, see Table 1.6
ID Name Setup 1
540.0 Function relay Comparator 0
Table 1.6 Comparator 0
The dampening of 1 second leads to suppressing of short term effects, see Table 1.7
ID Name Setup 1 Setup 2 Setup 3 Setup 4 Default value Unit
541.0 On Delay, Relay 1 0.01 0.01 0.01 0.01 s
ID Name Setup 1 Setup 2 Setup 3 Setup 4 Default value Unit
542.0 Off Delay, Relay 1 0.01 0.01 0.01 0.01 s
1 1
Table 1.7 Dampening
MI38U302 - VLT® is a registered Danfoss trademark 5
RCMB20/RCMB35
VLT® Leakage Current Monitor Module
11
1.1.9 Technical Data for Sensor RCMB20/RCMB35
Insulation coordination acc. to IEC 60664-1/IEC 60664-3
Rated insulation voltage AC 800 V
Rated impulse voltage/pollution degree 12 kV/2
Overvoltage category CAT III
Protective separation (reinforced insulation) between primary conductor and the measurement electronics
Voltage tests according to IEC 61010-1 6.88 kV
Supply voltage
Supply voltage U
s
Operating range of U
Ripple U
s
s
24 V DC
20.4...28.8 V
≤ 1 %
Power consumption ≤ 2.5 VA
Measuring circuit
Measuring current transformers RCMB20/RCMB35, inside diameter 20 mm/35 mm
Rated insulation voltage (measuring current transformer) 800 V
Operating characteristics according to IEC 62020 and IEC/TR 60755 AC/DC sensitive, Type B
Rated frequency 0...500 Hz
Measuring range AC/DC 0...500 mA
Nominal current at 3 N AC 32 A/80 A
Relative uncertainty for DC (RCMB20/RCMB35) ± 5%
Relative uncertainty for 10...30 Hz ± 10 %
Relative uncertainty for 30...400 Hz ± 3.5%
Relative uncertainty for 400....500 Hz ± 20%
Resolution measuring circuit 2 mA
Test winding yes
Time response
Response delay t
Delay on release t
on
off
Operating time tae at I
Response time t
an
Δn
0 s
≤ 1 s
≤ 180 ms
= tae + t
Recovery time tb ≤ 300 ms
Displays
LED constantly illuminated in green = operation indicator flashes red = fault (output current > 20 mA
Outputs
Current output 4...20 mA proportional to the leakage current
Current output, resolution IΔn = 31.25 x (analogue output current - 4 mA)
Load ≤ 300 Ω
Environment/EMC
EMC IEC 60947-2
Operating temperature -25...70 ºC
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-term storage (IEC 60721-3-1) 1K4 (except condensation and formation of ice)
on
6 MI38U302 - VLT® is a registered Danfoss trademark
RCMB20/RCMB35
VLT® Leakage Current Monitor Module
Classification of mechanical conditions acc. to IEC 60721
Stationary use (IEC 60721-3-3) .3M4
Transport (IEC 60721-3-2) 2M3
Storage (IEC 60721-3-1)
Chemical stresses acc. to IEC 60721 1M3
Stationary use (IEC 60721-3-3) 3C4
1.1.10 Connection
Primary conductor
RCMB20 ≤ 4 x 10 mm2 or 3 x 16 mm
RCMB35 ≤ 4 x 35 mm2 or 3 x 50 mm
Connector XK1
Connection type pluggable spring-cage terminals
Connection properties
Rigid 0,2...2,5 mm2 ( AWG 24...14)
Flexible without ferrules 0,2...2,5 mm2 ( AWG 24...14)
Flexible with ferrules 0,2...1,5 mm2 ( AWG 24...16)
Stripping length 10 mm
Opening force 50 N
General data
Operating mode continuous operation
Position any position
Degree of protection, internal components (DIN EN 60529) IP40
Degree of protection, terminals (DIN EN 60529) IP20
Enclosure material polycarbonate
Flammability class UL94 V-0
Screw mounting M5 with mounting brackets
DIN rail mounting acc. to IEC 60715
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1.1.11 Standards
The leakage current monitoring module is designed in accordance with the DIN EN 62020 standard
Code number
130B5645 A2-A3 20 mm DC 20.4...28.8 V
130B5764 B3 20 mm DC 20.4...28.8 V
130B5765 B4 35 mm DC 20.4...28.8 V
130B6226 C3 35 mm DC 20.4...28.8 V
130B5647 C4 35 mm DC 20.4...28.8 V
Table 1.8 Ordering Details
* Absolute values of the voltage ranges
Enclosure Inside diameter Supply voltage US*
MI38U302 - VLT® is a registered Danfoss trademark 7
www.danfoss.com/drives
130R0426 MI38U302 Rev. 2013-04-04
*MI38U302*
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