Mitsubishi Electric 700 Series, Instruction Manual

Page: 58 / 416

47
EMC and leakage currents
3
P
R
E
CAUTIONS FOR US
E
OF THE
IN
VE
RTE
R
(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:
Example
z
Selection example (in the case of the left figure (400V class connection))
z
Inverter leakage current (with and without EMC filter)
Input power conditions
(200V class: 220V/60Hz, 400V class: 440V/60Hz, power supply unbalance within 3%)
⋅
Breaker designed for harmonic and surge
suppression
Rated sensitivity current:
I
Δ
n
≥
10
×
(Ig1 + Ign + Igi + Ig2 + Igm)
⋅
Standard breaker
Rated sensitivity current:
I
Δ
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
Breaker Designed for
Harmonic and Surge
Suppression
Standard Breaker
Leakage current Ig1 (mA)
×
66
×
5m(16.40feet)
= 0.11
1000m(3280.80feet)
Leakage current Ign (mA) 0 (without noise filter)
Leakage current Igi (mA)
1 (without EMC filter)
Refer to the following table for the leakage current of the inverter*
Leakage current Ig2 (mA)
×
66
×
60m(196.86feet)
= 1.32
1000m(3280.80feet)
Motor leakage current Igm (mA) 0.36
Total leakage current (mA) 2.79 6.15
Rated sensitivity current (mA) 30 100
* Refer to page 15 for the presence/absence of the EMC filter.
Voltage
(V)
EMC Filter
ON (mA) OFF (mA)
200 22(1)* 1
400 30 1
400
1 1
*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
(200V 60Hz)
(200V 60Hz)
1. 5 3. 7
2. 2
7. 5 1522
11
37
30
55
45 5.5 18. 5
0. 1
0. 2
0. 3
0. 5
0. 7
1. 0
2. 0
0
2 0
4 0
6 0
8 0
100
120
2 3.5
5.5
8 1422
30
38
60
80
100
150
Motor capacity (kW)
Example of leakage current of
cable path per 1km during the
commercial power supply operation
when the CV cable is routed in
metal conduit
Leakage current example of
three-phase induction motor
during the commercial
power supply operation
Leakage currents (mA)
Leakage currents (mA)
Cable size (mm
2
)
Motor capacity (kW)
For " " connection, the amount of leakage current is appox.1/3 of the above value.
(Three-phase three-wire delta
connection 400V60Hz)
Example of leakage current per 1km during
the commercial power supply operation
when the CV cable is routed in metal conduit Leakage current example of three-
phase induction motor during the
commercial power supply operation
(Totally-enclosed fan-cooled
type motor 400V60Hz)
0
2 0
4 0
6 0
8 0
100
120
leakage currents (mA) leakage currents (mA) 2 3.5
5.5
8 1422
30
38
60
80
100
150
Cable size (mm 2 )
0. 1
0. 2
0. 3
0. 5
0. 7
1. 0
2. 0
1. 5 3. 7
2. 2
7. 5 1522
11
37
30
55
45 5.5 18. 5
Noise
filter
Inverter
ELB
Ig1 Ign
Igi
Ig2 Igm
IM
5.5mm
2 ×
5m(16.40feet)
5.5mm
2 ×
60m(196.86feet)
400V
2.2kW
(3HP)
3
φ
1
3
1
3
Phase
grounding
Earthed-neutral
system