Mitsubishi Electric FR-CC2-P, Инструкция по эксплуатации

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Main circuit terminals (6-phase rectification)
38
INSTALLATION AND WIRING
2.5.4
Earthing (grounding) precautions
• Always earth (ground) the converter unit.
 Purpose of earthing (grounding)
Generally, an electrical apparatus has an earth (ground) terminal, which must be connected to the ground before use.
An electrical circuit is usually insulated by an insulating material and encased. However, it is impossible to manufacture an
insulating material that can shut off a leakage current completely, and actually, a slight current flows into the case. The
purpose of earthing (grounding) the case of an electrical apparatus is to prevent operators from getting an electric shock from
this leakage current when touching it.
To avoid the influence of external noises, this earthing (grounding) is important to audio equipment, sensors, computers and
other apparatuses that handle low-level signals or operate very fast.
 Earthing (grounding) methods and earthing (grounding) work
As described previously, earthing (grounding) is roughly classified into an electrical shock prevention type and a noise-
influenced malfunction prevention type. Therefore, these two types should be clearly distinguished, and the following work
must be done to prevent the leakage current having the converter unit's high frequency components from entering for
malfunction prevention:
• Whenever possible, use the independent earthing (grounding) for the converter unit.
Establishing adequate common (single-point) earth (ground) system (II) shown in the following figure is allowed only in
cases where the separate earth (ground) system (I) is not feasible. Do not make inadequate common (single-point) earth
(ground) connection (III).
A leakage current containing many high frequency components flows into the earthing (grounding) cables of the converter
unit. Because of this, the converter unit must be earthed (grounded) separately from EMI-sensitive devices.
In a high building, it may be effective to use the EMI prevention type earthing (grounding) connecting to an iron structure
frame, and electric shock prevention type earthing (grounding) with the independent earthing (grounding) together.
• 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).
A neutral-point earthed (grounded) power supply in compliance with EN standard must be used.
• Use the thickest possible earthing (grounding) cable. The size of the earthing (grounding) cable should be the same or
larger than the one indicated in the table on page 37 .
• The earthing (grounding) point should be as close as possible to the converter unit, and the earth (ground) wire length
should be as short as possible.
• Run the earthing (grounding) cable as far away as possible from the I/O wiring of equipment sensitive to noises and run
them in parallel in the minimum distance.
NOTE
• To be compliant with the EU Directive (Low Voltage Directive), refer to page 172 .
Inverter/
converter
unit
Other equipment
(incl. inverter /
converter unit)
(I) Separate earthing (grounding).......Good
(II) Common (single-point) earthing (grounding).......OK
Inverter/
converter
unit
Other equipment
(incl. inverter /
converter unit)
(III) Inadequate common (single-point) earthing(grounding).......Bad
Inverter/
converter
unit
Other equipment
(incl. inverter /
converter unit)