41
EMC and leakage currents
3
PRE
CAU
TI
ONS
FOR
USE
OF
T
HE
INV
E
R
T
ER
(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
(400V class: 440V/60Hz, power supply unbalance within 3%)
Breaker designed for harmonic and surge
suppression
Rated sensitivity current:
I
'
n
t
10
u
(Ig1 + Ign + Igi + Ig2 + Igm)
Standard breaker
Rated sensitivity current:
I
'
n
t
10
u
{Ig1 + Ign + Igi + 3
u
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)
u
66
u
5m
= 0.11
1000m
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)
u
66
u
60m
= 1.32
1000m
Motor leakage current Igm (mA)
0.36
Total leakage current (mA)
2.79
6.15
Rated sensitivity current (mA)
30
100
*
Refer to page 13
for the presence/absence of the EMC filter.
Voltage
(V)
EMC Filter
ON (mA)
OFF (mA)
400
30
1
400
1
1
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
earth fault in the inverter output side. Earthing
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
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
5.5mm
2
×
60m
400V
2.2kW
3
φ
1
3
1
3
Phase
earthing
Earthed-neutral
system
Summary of Contents for F700
Page 327: ...318 MEMO ...
Page 340: ...331 MEMO ...
