Selecting Rated Sensitivity Current For Earth Leakage Circuit Breaker - Mitsubishi Electric FR-XC-18.5K-PWM Instruction Manual

1.4.3
Selecting the rated sensitivity current for the
earth leakage circuit breaker
To install the earth leakage circuit breaker on the inverter circuit, select its rated sensitivity current as follows.
• Breaker designed for harmonic and surge suppression
Rated sensitivity current
I∆n ≥ 10 × (Ig1 + Ign + Ig2 + Ig3 + Igm)
• Standard breaker
Rated sensitivity current
I∆n ≥ 10 × {Ig1 + Ign + Ig2 + 3 × (Ig3 + 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
(200 V 60 Hz)
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
2
5.5 mm ×5 m 5.5 mm
[Example]
ELB
Noise
filter
FR-XC
converter
lg1 lgn
• Multifunction regeneration converter leakage current
Input power conditions
: 220 V/60 Hz (200 V class) or 440 V/60 Hz (400 V class), within 3% of power supply unbalance
Voltage
(V)
200
Phase
earthing
400
(grounding)
Earthed-neutral
400
system
Leakage current example of
three-phase induction motor
during the commercial
power supply operation
(200 V 60 Hz)
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)
2 2
×5 m 5.5 mm ×70 m
3φ
Inverter IM
200 V 2.2 kW
lgm
lg2 lg3
Leakage
current
(mA)
2
4
4
Precautions for selecting peripheral devices
Ig1, lg2, lg3: Leakage currents in wire path during
commercial power supply operation
Ign: Leakage current from noise filters on the input side
of the converter
Igm: Leakage current from the motor during
commercial power supply operation
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 400 V 60 Hz)
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.
Selection example (diagram shown on the left) (mA)
Leakage current lg1 (mA)
Leakage current lgn (mA)
Leakage current lg2 (mA)
Leakage current lg3 (mA)
Leakage current lgm (mA)
Total leakage current
(mA)
Rated sensitivity current
(≥ Ig × 10) (mA)
Leakage current example of three-
phase induction motor during the
commercial power supply operation
(Totally-enclosed fan-cooled
type motor 400 V 60 Hz)
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)
Breaker
designed for
Standard
harmonic and
breaker
surge
suppression
5 m
33 × = 0.17
1000 m
0 (without noise filter)
5 m
33 × = 0.17
1000 m
70 m
33 × = 2.31
1000 m
0.18
2.83 7.81
30 100
OUTLINE
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