Selection Of Rated Sensitivity Current Of Earth (Ground) Leakage Current Breaker; Selection Example (In The Case Of The Left Figure); Inverter Leakage Currents (With And Without Emc Filter) - Mitsubishi Electric FR-A700 Manual

Selection of rated sensitivity current of earth (ground) leakage current 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 currentI∆n≥10 (Ig1+Ign+lgi+Ig2+Igm)
⋅
Standard breaker
×
Rated sensitivity currentI∆n≥10 {(Ig1+Ign+Igi+3
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 : Inverter unit leakage current
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)
2. 0
120
100
1. 0
8 0 0. 7
0. 5
6 0
0. 3
4 0
0. 2
2 0
0 0. 1
2 3.5 8 1422 38 80 150
5.5 30 60 100
Power supply size (mm 2 )
Example
2 2
× 5m × 50m
5.5mm 5.5mm
ELB
Noise
filter
Inverter
Ig1 Ign Ig2
Igi
Note:1. Install the earth leakage current breaker (ELB) on the input side of the inverter.
2. In the connection earthed-neutral system, the sensitivity current is purified
against an earth (ground) fault in the inverter output side. Earthing (Grounding)
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)
.
×
(Ig2+Igm)}
Leakage current example of
three-phase induction motor
during the commercial
power supply operation
(200V 60Hz)
1. 5 3. 7 7. 5 1522 37 55
2. 2 5.5 11 18. 5 30 45
Motor capacity (kW)
3φ
IM
200V
2.2kW
Igm

Selection example (in the case of the left figure)

Breaker Designed For
Harmonic and Surge
Suppression
Leakage current
Ig1 (mA)
Leakage current
0 (without noise filter)
Ign(mA)
1 (without EMC filter)
Leakage current
Refer to the following table for the leakage
Igi(mA)
current of the inverter
Leakage current
Ig2(mA)
Motor leakage
current Igm
(mA)
Total leakage
3.00
current (mA)
Rated sensitivity
current (mA)
30
≥ ×
( Ig 10)

Inverter leakage currents (with and without EMC filter)

Input power conditions
(200V class: 220V/60Hz, 400V class: 440V/60Hz,
power supply unbalance within 3%)
Voltage
Earth (Ground)
(V)
200
Phase
grounding
400
Earthed-neutral
system
400
* For the 200V class 0.4K and 0.75K, the EMC filter is always valid.
The leakage current is 1mA.
Standard
Breaker
5m
×
=0.17
33
1,000m
50m
×
=1.65
33
1,000m
0.18
6.15
100
EMC Filter
ON (mA) OFF (mA)
22 (1) 1
*
30 1
1 1
88