Mitsubishi Electric F700 Instruction Manual page 37

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(3) Selection of rated sensitivity current of earth (ground) 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
* Note the leakage current value of the noise filter installed on the inverter input side.
Example
2
× 5m
5.5mm 5.5mm
ELB
Noise
filter
Inverter
Ig1 Ign
Igi
CAUTION
⋅ Install the earth leakage breaker (ELB) on the input side of the inverter.
⋅ A ground fault on the output side of the inverter can be detected at the running frequency of 120Hz or less.
⋅ 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
30
Leakage current Ig1 (mA)
2
× 60m
Leakage current Ign (mA)
3φ
IM
400V
2.2kW
Leakage current Igi (mA)
Ig2 Igm
Leakage current Ig2 (mA)
Motor leakage current Igm (mA)
Total leakage current (mA)
Rated sensitivity current (mA)
* Refer to page 34 for the presence/absence of the EMC filter.
Inverter leakage current (with and without EMC filter)
Phase
grounding
Earthed-neutral
system
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
Power supply size
For " " connection, the amount of leakage current is 1/3
Breaker Designed
for Harmonic and
Surge Suppression
1
3
Refer to the following table for the leakage
1
3
EMC Filter
Voltage
(V)
ON (mA)
400 30
400 1
Leakage current example of
3-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
8 1422 38 80 150 1. 5 3. 7 7. 5 1522
5.5 30 60 100 2. 2 5.5 11
(mm 2 ) Motor capacity (kW)
Standard Breaker
5m
× 66 ×
= 0.11
1000m
0 (without noise filter)
1 (When there is no EMC filter)
current of the inverter*
60m
× 66 ×
= 1.32
1000m
0.36
2.79 6.15
30 100
OFF (mA)
1
1
37 55
18. 5 30 45