18
4.
Connecting
the
load
4-1
Cables
to
be
used
Selection
of
cables
Use cables having sufficient size in consideration of the allowable current of the
cables and the distance between the machine and the load.
If the load current exceeds the allowable current of cables, the cable may be damaged
by overheat. Also, if the cables are too small in size for the length, the input voltage of
the load drops which lowers the working efficiency or causes failure in operation.
Select the length and size of cable so that the voltage drop "e" obtained by the
following equation is within 5% of the rated voltage.
* Equation to obtain 3-phase, 3-wire system voltage drop "e" from the length and size
of cable and operating current is as follows
e =
58
1
×
L
S
×
I
×
3
