Mitsubishi Electric FR-F740-00023-EC Instruction Manual page 46

(3) Selection of rated sensitivity current of earth leakage breaker
When using the earth leakage circuit breaker with the inverter circuit, select its rated sensitivity current as follows,
independently of the PWM carrier frequency:
⋅ Breaker designed for harmonic and surge suppression
Rated sensitivity current:
I∆n ≥ 10 × (Ig1 + Ign + Igi + Ig2 + Igm)
⋅ Standard breaker
Rated sensitivity current:
I∆n ≥ 10 × {Ig1 + Ign + Igi + 3 × (Ig2 + Igm)}
Ig1, Ig2: Leakage currents in wire path during commercial power
supply operation
Ign: Leakage current of inverter input side noise filter
Igm: Leakage current of motor during commercial power supply
operation
Igi: Leakage current of inverter unit
Example
2 2
× 5m
5.5mm 5.5mm
ELB
Noise
filter
Inverter
Ig1 Ign Ig2
Igi
Inverter leakage current (with and without EMC filter)
Input power conditions
(400V class: 440V/60Hz, power supply unbalance within 3%)
Earthed-neutral
system
CAUTION
⋅ Install the earth leakage breaker (ELB) on the input side of the inverter.
⋅ In the
connection earthed-neutral system, the sensitivity current is purified against an earth fault in the inverter output side.
Earthing must conform to the requirements of national and local safety regulations and electrical codes. (JIS, NEC section 250,
IEC 536 class 1 and other applicable standards)
⋅ When the breaker is installed on the output side of the inverter, it may be unnecessarily operated by harmonics even if the
effective value is less than the rating.In this case, do not install the breaker since the eddy current and hysteresis loss will
increase, leading to temperature rise.
⋅ The following models are standard breakers....BV-C1, BC-V, NVB, NV-L, NV-G2N, NV-G3NA and NV-2F earth leakage relay
(except NV-ZHA), NV with AA neutral wire open-phase protection
The other models are designed for harmonic and surge suppression....NV-C/NV-S/MN series, NV30-FA, NV50-FA, BV-C2,
earth leakage alarm breaker (NF-Z), NV-ZHA, NV-H
Leakage current Ig1 (mA)
× 60m
Leakage current Ign (mA)
3φ
IM
400V
2.2kW
Leakage current Igi (mA)
Igm
Leakage current Ig2 (mA)
Motor leakage current Igm (mA)
Total leakage current (mA)
Rated sensitivity current (mA)
* Refer to page 5 for the presence/absence of the EMC filter.
Voltage
(V)
Phase
400
earthing
400
Example of leakage current
per 1km during the commercial
power supply operation when
the CV cable is routed in
metal conduit
(Three-phase three-wire delta
connection 400V60Hz)
120
100
8 0
6 0
4 0
2 0
0
2 3.5 8 1422
5.5
Power supply size
For " " connection, the amount of leakage current is 1/3
Breaker Designed for
Harmonic and Surge
Suppression
1
× 66 ×
3
Refer to the following table for the leakage current
1
× 66 ×
3
2.79
EMC Filter
OFF (mA)
ON (mA)
30 1
1 1
Noise and leakage currents
Leakage current example of
Three-phase induction motor
during the commercial
power supply operation
(Totally-enclosed fan-cooled
type motor 400V60Hz)
2. 0
1. 0
0. 7
0. 5
0. 3
0. 2
0. 1
38 80 150 1. 5 3. 7 7. 5 1522 37 55
30 60 100 2. 2 5.5 11 18. 5 30 45
(mm 2 ) Motor capacity (kW)
Standard Breaker
5m
= 0.11
1000m
0 (without noise filter)
1 (without EMC filter)
of the inverter*
60m
= 1.32
1000m
0.36
6.15
30 100
2
35