37
2. INSTALLATION AND WIRING
2.5 Main circuit terminals (for 6-phase rectification)
1
2
3
4
5
6
7
8
9
10
*1
The cable size is that of the PVC cable with continuous maximum permissible temperature of 70°C. It assumes a surrounding air temperature of
40°C or lower and in-enclosure wiring. (Selection example mainly for use in Europe.)
*2
It is applied to the screws for terminals R/L1, S/L2, T/L3, P/+, and N/-, and a screw for earthing (grounding). Screw size for earthing (grounding)
is indicated in parentheses.
The line voltage drop can be calculated by the following formula:
Line voltage drop [V] =
Use a larger diameter cable (or a bus bar) when the wiring distance is long or when it is desired to decrease the voltage drop
(torque reduction) in the low speed range.
NOTE
• Tighten terminal screws to the specified torque.
A screw that has been tightened too loosely can cause a short circuit or malfunction.
A screw that has been tightened too tightly can cause a short circuit or malfunction due to the unit breakage.
• Use crimp terminals with insulation sleeves to wire the power supply and motor.
• The creepage distance between terminals is 16.3 mm. When more insulation distance is required, secure a sufficient distance
or use insulating material for bus bars.
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, the earthing (grounding) is important to EMI-sensitive equipment that handle low-
level signals or operate very fast such as audio equipment, sensors, computers.
Earthing (grounding) system to be established
As described previously, the purpose of earthing (grounding) is roughly classified into the electrical shock prevention and the
prevention of malfunction due to the influence of electromagnetic noise. 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 the malfunction prevention type earthing (grounding):
• 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).
As leakage currents containing many high frequency components flows into the earthing (grounding) cables of the
converter unit, the converter unit must also be earthed (grounded) separately from the EMI-sensitive equipment described
above.
In a high building, it may be effective to use its iron structure frames as earthing (grounding) electrode for EMI prevention
in order to separate from the earth (ground) system for electric shock prevention.
• Earthing (grounding) must conform to the requirements of national and local safety regulations and electrical code (NEC
section 250, IEC 61140 class 1 and other applicable standards).
• Use the thickest possible earthing (grounding) cable. The earthing (grounding) cable should be the size indicated in the
table on
• 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.
× wire resistance [mΩ/m] × wiring distance [m] × current [A]
1000
Содержание FR-CC2-N Series
Страница 61: ...60 3 PRECAUTIONS FOR USE OF THE CONVERTER UNIT 3 4 Checklist before starting operation MEMO ...
Страница 137: ...136 5 PARAMETERS 5 10 Checking parameters changed from their initial values initial value change list MEMO ...
Страница 153: ...152 6 PROTECTIVE FUNCTIONS 6 6 Check first when you have a trouble MEMO ...
Страница 165: ...164 7 PRECAUTIONS FOR MAINTENANCE AND INSPECTION 7 2 Measurement of main circuit voltages currents and powers MEMO ...
Страница 171: ...170 8 SPECIFICATIONS 8 3 Outline dimension drawings MEMO ...