Mitsubishi Electric FR-F720-00046 Instruction Manual page 56

(3) Selection of rated sensitivity current of earth leakage circuit breaker
When using the earth leakage current 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:
IΔn ≥ 10 × (Ig1 + Ign + Igi + Ig2 + Igm)
⋅ Standard breaker
Rated sensitivity current:
IΔn ≥ 10 × {Ig1 + Ign + Igi + 3 × (Ig2 + Igm)}
Example of leakage current of
cable path per 1km during the
commercial power supply operation
when the CV cable is routed in
metal conduit
(200V 60Hz)
120
100
8 0
6 0
4 0
2 0
0
2 3.5 8 1422 38 80 150
5.5 30 60 100
Cable size (mm 2 )
Example
2 × 2
5.5mm 5.5mm
5m(16.40feet) 60m(196.86feet)
ELB
Noise
filter
Inverter
Ig1 Ign Ig2
Igi
Inverter leakage current (with and without EMC filter)
Input power conditions
(200V class: 220V/60Hz, 400V class: 440V/60Hz, power supply unbalance within 3%)
Phase
grounding
Earthed-neutral
system
*For the FR-F720-00046 and FR-F720-00077, the EMC filter is
always valid. The leakage current is 1mA.
CAUTION
⋅ Install the earth leakage circuit breaker (ELB) on the input side of the inverter.
⋅ In the
connection earthed-neutral system, the sensitivity current is blunt against an ground fault in the inverter output side.
Grounding must conform to the requirements of national and local safety regulations and electrical codes. (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 example of
three-phase induction motor
during the commercial
power supply operation
(200V 60Hz)
2. 0
1. 0
0. 7
0. 5
0. 3
0. 2
0. 1
1. 5 3. 7 7. 5 1522 37 55
2. 2 5.5 11 18. 5 30 45
Motor capacity (kW)
Selection example (in the case of the left figure (400V class
×
Leakage current Ig1 (mA)
Leakage current Ign (mA)
3φ
400V
IM
Leakage current Igi (mA)
2.2kW
(3HP)
Igm
Leakage current Ig2 (mA)
Motor leakage current Igm (mA)
Total leakage current (mA)
Rated sensitivity current (mA)
* Refer to page 15 for the presence/absence of the EMC filter.
Voltage
(V)
200
400
400
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 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 38 80 150
5.5 30 60 100
Cable size (mm 2 )
For " " connection, the amount of leakage current is appox.1/3 of the above value.
Breaker Designed for
Harmonic and Surge
Suppression
1
× 66 ×
3
Refer to the following table for the leakage current of the inverter*
1
× 66 ×
3
2.79
30
EMC Filter
ON (mA) OFF (mA)
22(1)* 1
30 1
1 1
EMC 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
1. 5 3. 7 7. 5 1522 37 55
2. 2 5.5 11 18. 5 30 45
Motor capacity (kW)
connection))
Standard Breaker
5m(16.40feet)
= 0.11
1000m(3280.80feet)
0 (without noise filter)
1 (without EMC filter)
60m(196.86feet)
= 1.32
1000m(3280.80feet)
0.36
6.15
100
3
47