Mitsubishi Electric FR-A520-0.4K -55K Instruction Manual page 51

( 2 ) Selection the rated sensitivity current for the earth leakage circuit breaker
When using the earth leakage circuit breaker with the inverter circuit, select its rated sensitivity current as
follows, independent of the carrier frequency setting:
• Progressive Super Series (Type SP, CP)
Rated sensitivity current:
l∆n ≥ 10 × (lg
+ lgn + lg + lgm)
1 2
• Conventional NV series (Type CA, CS, SS)
Rated sensitivity current:
l∆n ≥ 10 × {lg + lgn + 3 × (lg
1
lg , lg : leakage currents of cable path
1 2
during commercial power supply
operation
lgn* : leakage current of noise filter on
inverter input side
lgm : leakage current of motor during
commercial power supply operation
<Example>
2 2
5.5mm • ~ 5m 5.5mm • ~ 70m
(16.40 feet) (229.66 feet)
NV
Noise
filter
Inverter
Ig1 Ign Ig2
Note 1. The NV should be installed to the
primary (power supply) side of the
inverter.
2. Ground fault in the secondary side of the
inverter can be detected at the running
frequency of 120Hz or lower.
3. If the Y connection neutral point ground
fault in the inverter secondary side.
The protective ground resistance of the
load equipment should be 10Ω or less.
4. When the breaker is grounded on the secondary side of the inverter, it may be unnecessarily
operated by harmonics if the effective value is less than the rating. In this case, note that the eddy
current and hysteresis loss increase and temperature rises.
* For the leakage current value of the noise filter installed on the inverter input side, contact the
corresponding filter manufacturer.
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Example of leakage current
per 1kW in cable path during
commercial power supply
operation when the CV
cable is routed in metal
conduit (200V 60Hz)
+lgm)}
2
120
100
80
60
40
20
0
2 3.5
3ƒ Ó
IM
200V 2.2kW (3HP)
Igm
Leakage current Ig1
Leakage current Ign
Leakage current Ig2
Motor leakage current Igm
Total leakage current
Reted sensitivity current
( ≥Ig × 10)
40
INSTALLATION AND WIRING
Leakage current example
of 3-phase induction motor
during commercial power
supply operation
(200V 60Hz)
2.0
1.0
0.7
0.5
0.3
0.2
0.1
8 14 22 38 80 150 1.5 3.7
5.5 30 60 100 2.2
2
Cable size (mm ) Motor capacity (kW)
Progressive Super
Series
(Type CA, CS, SS)
(Type SP, CP)
5m (16.40 feet)
33 ×
1000m (3280.80 feet)
0 (without noise filter)
70m (229.66 feet)
33 ×
1000m (3280.80 feet)
0.18
2.66
30
7.5 15 22 37 55
5.5 11 18.5 30 45
Conventional NV
= 0.17
= 2.31
7.64
100