Digitax HD M75X Series Installation and Technical Guide
55
Issue Number: 5
Use 105 °C (221 °F) (UL 75 °C temp rise) PVC-insulated cable with copper conductors having a suitable voltage rating, for the following power
connections:
•
AC supply (or external EMC filter) to drive.
•
Drive to braking resistor.
Input cable sizes should generally be regarded as a minimum, since they have been selected for co-ordination with the recommended fuses.
The drive power terminals are designed for a maximum cable size of 10 mm
²
(8 AWG), (minimum 0.05 mm / 30 AWG). Where more than one cable
per terminal is used the combined diameters should not exceed the maximum. The terminals are suitable for both solid and stranded wires.
An MCB (miniature circuit breaker) may be used in place of fuses under the following conditions:
•
The fault-clearing capacity must be sufficient for the installation
•
The I
²
T rating of the MCB must be less than or equal to that of the fuse rating listed above.
A fuse or other protection must be included in all live connections to the AC supply.
For a parallel DC bus system the maximum AC input fusing is shown in Table 4-7.
Table 4-7 Maximum AC input fusing
on page 84 for further information regarding DC bus paralleling.
4.7 Output circuit and motor protection
The output circuit has fast-acting electronic short-circuit protection which limits the fault current to typically no more than five times the rated output
current, and interrupts the current in approximately 20 µs. No additional short-circuit protection devices are required.
The drive provides overload protection for the motor and its cable. For this to be effective,
Rated Current
(
05.007
) must be set to suit the motor
There is also provision for the use of a motor thermistor to prevent over-heating of the motor, e.g. due to loss of cooling.
4.7.1
Motor cable types
Since capacitance in the motor cable causes loading on the output of the drive, ensure the cable length does not exceed the values given in Table 4-
8.
Cable sizes are given for guidance only and may be changed depending on the application and the method of installation of the cables.
The mounting and grouping of cables affect their current capacity, in some cases a larger cable is required to avoid excessive temperature or voltage
drop.
The recommended output cable sizes assume that the motor maximum current matches that of the drive. Where a motor of reduced rating is used the
cable rating may be chosen to match that of the motor. To ensure that the motor and cable are protected against overload, the drive must be
programmed with the correct motor rated current (Pr
05.007
).
•
Cable lengths in excess of the specified values may be used only when special techniques are adopted; refer to the supplier of the drive.
Model
Fuse rating
Fuse rating
Input cable size
IEC class gG
UL class J
mm
2
AWG
All
40
40
6
8
Rated Current
(
05.007
) must be set correctly to avoid a risk of fire in the event of motor overload.
NOTE
WARNING
NOTE
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