Countermeasures Against Inverter-Generated Emi - Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual

Example
2
5.5 mm 5 m
ELB
Noise
filter
Inverter
Ig1 Ign
Igi
Inverter leakage current (with and without EMC filter)
Phase
earthing
(grounding)
Earthed-neutral
system
NOTE
• Install the earth leakage circuit breaker (ELB) on the input side of the inverter.
• In the
Earthing (Grounding) must conform to the requirements of national and local safety regulations and electrical codes. (NEC
section 250, IEC 61140 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 within 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, NV-2F, earth leakage relay
(except NV-ZHA), and 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, and NV-H.
3.1.2

Countermeasures against inverter-generated EMI

Some electromagnetic noises enter the inverter to cause the inverter malfunction, and others are radiated by the inverter to
cause the peripheral devices to malfunction. Though the inverter is designed to have high immunity performance, it handles
low-level signals, so it requires the following basic techniques. Also, since the inverter chops outputs at high carrier frequency,
that could generate electromagnetic noises. If these electromagnetic noises cause peripheral devices to malfunction, EMI
countermeasures should be taken to suppress noises. These techniques differ slightly depending on EMI paths.
 Basic techniques
• Do not run the power cables (I/O cables) and signal cables of the inverter in parallel with each other and do not bundle
them.
• Use shielded twisted pair cables for the detector connecting and control signal cables and connect the sheathes of the
shielded cables to terminal SD.
• Ground (Earth) the inverter, motor, etc. at one point.
116
3. PRECAUTIONS FOR USE OF THE INVERTER
3.1 Electro-magnetic interference (EMI) and leakage currents
2
5.5 mm 50 m
3φ
M
200 V
2.2 kW
Ig2 Igm
EMC filter
Voltage
(V)
ON (mA)
200 22
400 35
400 2
connection earthed-neutral system, the sensitivity current is blunt against a ground fault in the inverter output side.
Item
Leakage current Ig1 (mA)
Leakage current Ign (mA)
Leakage current Igi (mA)
Leakage current Ig2 (mA)
Motor leakage current Igm
(mA)
Total leakage current (mA)
Rated sensitivity current (mA)
(≥ Ig × 10)
OFF (mA)
1
2
Input power conditions
220 V/60 Hz (200 V class) or 440 V/60 Hz
(400 V class), within 3% of power supply
unbalance
1
Breaker designed
for harmonic and
surge suppression
5m
33 × = 0.17
1000m
0 (without noise filter)
1 (without EMC filter)
For the leakage current of the inverter, refer to
the following table.
50m
33 × = 1.65
1000m
0.18
3.00
30
Remarks
Standard breaker
6.66
100