MITSUBISHI ELECTRIC FR-S520E User Manual
Page 33
23
1
WI
RING
2) Calculation of outgoing harmonic current
Outgoing harmonic current = fundamental wave current (value converterd from
received power voltage) × operation ratio × harmonic
content
• Operation ratio: Operation ratio = actual load factor × operation time ratio during
30 minutes
• Harmonic content: Found in Table 4.
3) Harmonic suppression technique requirement
If the outgoing harmonic current is higher than; maximum value per 1kW (contract
power) × contract power, a harmonic suppression technique is required.
4) Harmonic suppression techniques
Table 5
Rated Capacities and Outgoing Harmonic Currents for Inverter Drive
Applied
Motor
(kW)
Rated
Current [A]
6.6kV
Equivalent of
fundamental
wave input
current (mA)
Input
rated
capacity
(kVA)
Outgoing Harmonic Current Converted from
6.6kV (mA)
(without reactor, 100% operation ratio)
200V 400V
5th
7th
11th 13th 17th 19th 23rd 25th
0.4
1.61 0.81
49
0.57
14.7 6.37 4.12 2.45 2.30 1.57 1.47 1.08
0.75
2.74 1.37
83
0.97
24.9 10.76 6.97 4.15 3.90 2.66 2.49 1.83
1.5
5.50 2.75
167
1.95
50.10 21.71 14.03 8.35 7.85 5.34 5.01 3.67
2.2
7.93 3.96
240
2.81
72.00 31.20 20.16 12.00 11.28 7.68 7.20 5.28
3.7
13.0 6.50
394
4.61
118.2 51.2 33.10 19.70 18.52 12.61 11.82 8.67
No.
Item
Description
1
Reactor installation
(ACL, DCL)
Install a reactor (ACL) in the AC side of the inverter or a reactor
(DCL) in its DC side or both to suppress outgoing harmonic
currents.
2
Installation of power
factor improving
capacitor
When used with a series reactor, the power factor improving
capacitor has an effect of absorbing harmonic currents.
3
Transformer multi-
phase operation
Use two transformers with a phase angle difference of 30
°
as in
-
∆
,
∆
-
∆
combination to provide an effect corresponding to 12 pulses,
reducing low-degree harmonic currents.
4
Passive
(AC filter)
A capacitor and a reactor are used together to reduce impedances
at specific frequencies, producing a great effect of absorbing
harmonic currents.
5
Active filter
This filter detects the current of a circuit generating a harmonic
current and generates a harmonic current equivalent to a difference
between that current and a fundamental wave current to suppress
a harmonic current at a detection point, providing a great effect of
absorbing harmonic currents.