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4.1.2 Peripheral device list
4.1.3 Selecting the rated sensitivity current for the earth leakage circuit breaker
When using the earth leakage circuit breaker with the inverter circuit, select its rated sensitivity current as follows:
• Breaker for harmonic and surge
Rated sensitivity current: I n 10×(lg1+lg2+lg3+lgm)
• Standard breaker
Rated sensitivity current:
In10×{lg1+lgn+lg2+3×(lg3+lgm)}
where, lg1, lg2, lg3:leakage currents of cable path
during commercial power supply operation
lgn* :leakage current of noise filter on converter
input side
lgm :leakage current of motor during commercial
power supply operation
Note: 1.Install the NV on the primary (power supply) side
of the power return common converter.
2.Ground fault on the output side of the inverter can
be detected at the running frequency of 120Hz or
lower.
3.In the connection neutral point grounded system,
the sensitivity current becomes worse for ground
faults in the inverter secondary side. Hence, the
protective grounding of the load equipment should
be class C grounding (10 Ω or less).
4.When the breaker is installed in the secondary
side of the inverter, it may be unnecessarily
operated by harmonics if the effective value is
less than the rating. In this case, do not install the
breaker since the eddy current and hysteresis
loss increase and the temperature rises.
5.The following models are standard breakers Type BV-
C1, BC-V, NVB, NV-L, NV-G2N, NV-G3NA, NV-2F
type leakage current relay (except for NV-ZHA), NV
with AA neutral wire open-phase protection
The following models are for harmonic surge
NV-C/NV-S/MN series, NV30-FA, NV50-FA, BV-C2, leakage current alarm breaker (NF-Z), NV-ZHA, NV-H
* Note the leakage current value of the noise filter installed on the high power factor converter input side.
(For Mitsubishi’s dedicated filters, see page 71.)
Voltage
High Power Factor
Converter Type
No-fuse breaker (NFB note 1)
or leakage breaker (NV) (note 2)
Magnetic
Contactor (MC)
200V class
FR-HC-7.5K 50AF 50A S-N35
FR-HC-15K 100AF 75A S-N65
FR-HC-30K 225AF 125A S-N125
FR-HC-55K 225AF 225A S-N220
400V class
FR-HC-H7.5K 30AF 30A S-N20
FR-HC-H15K 50AF 50A S-N25
FR-HC-H30K 100AF 75A S-N65
FR-HC-H55K 225AF 125A S-N125
Note: 1.Select the NFB according to the capacity of the high power factor converter and install one NFB
per high power factor converter.
2.For installations in the United States or Canada, the circuit breaker must be inverse time or
instantaneous trip type.
3.When the breaker on the primary side of the high power factor converter tripped, check for wiring
fault (e.g.short circuit), damage to internal parts of the inverter (high power factor converter), etc.
Identify the cause of the breaker trip, then power on the breaker after removing the cause of the trip.
Example of leakage current per
1km in cable path during com-
mercial power supply operation
when the CV cable is routed in
metal conduit (200V 60Hz)
Leakage Current Example of
3-Phase Induction Motor dur-
ing Commercial Power Sup-
ply Operation (200V 60Hz)
120
100
80
60
40
20
0
23.5
5.5
814223880150
30 60 100
Cable size (mm
2
)
2.0
1.0
0.7
0.5
0.3
0.2
0.1
1.5
2.2
3.7
5.5
7.5 15223755
1118.5 30 45
Motor capacity (kW)
(mA)
Leakage current
(mA)
Leakage current
∆
>
∆
>
<Example>
lg1 lgn lg2 lg3
lgm
3
φ
200V 2.2kW
IM
Inverter
Noise
filter
NV
5.5mm
2
×5m 5.5mm
2
×50m 5.5mm
2
×70m
High
power
factor
converter
Selection Example
(for the diagram shown on the left) (mA)
Breaker for
harmonic and surge
Standard
Breaker
Leakage current lg1
(mA)
33× =0.17
Leakage current lgn
(mA)
0 (without noise filter)
Leakage current lg2
(mA)
33× =1.65
Leakage current lg3
(mA)
33× =2.31
Motor leakage
current lgm (mA)
0.18
Total leakage current
(mA)
4.31 7.97
Rated sensitivity cur-
rent ( lg×10) (mA)
30 100
5m
1000m
------------------
50m
1000m
------------------
70m
1000m
------------------
>
=