1.3 Wiring (for looms other than towel weaving machine)
39
[ 4 ] Cable selection
Select the cable according to steps [1], [2] and [3].
(1) Obtain the current flowing in cable
①
between the circuit breaker on the switchboard and the inverter.
Select the cable according to the value obtained by the equation below.
(2) Obtain the current flowing in the cable
②
between the inverter and loom.
Obtain the current s at slow operation (3.4
×
In) in [2].
The value in [3] is used for In.
Current value = 3.4
×
In
(3) Select cables
①
and
②
so that the total voltage drop by supply voltage fluctuation and by cables
①
and
②
is within 15 - 20%.
(4) Obtain the current flowing in cable
③
between the circuit breaker on the switchboard and loom.
Obtain the current s at delta starting (20
×
In) in [2].
Use the value in [3] for the In.
Current value = 20
×
In
NOTE:
The electronic shedding loom requires additional current to operate the electronic shedding
motor besides the starting current (20
×
In) as the current used for the loom. The following are the rough
calculation formulas for obtaining the total current value.
•
Shedding motion for 8 frames
Current value = 20
×
In +
•
Shedding motion for 10 frames
Current value = 20
×
In +
•
Shedding motion for 12 frames
Current value = 20
×
In +
•
Shedding motion for 16 frames
Current value = 20
×
In +
(5) Select cable
③
so that the total voltage drop by supply voltage fluctuation and by cable
③
becomes
within 10%.
Current value = inverter rating (kVA)
×
1.5
×
0.2
×
1.7
/ (
×
plant supply voltage [V]) [A]
Coefficient considering the loss by
inverter high harmonic component ,
inverter input/output conversion coeffi-
cient and margin
Inverter output voltage/motor rated volt-
age (Power supply voltage)
Inverter short-time overload capacity
3
6500
×
Power supply voltage (V)
3
7300
×
Power supply voltage (V)
3
8000
×
Power supply voltage (V)
3
9500
×
Power supply voltage (V)
3
