Maximum Connectable Motor Cable Lengths; Booksize Units - Siemens SINAMICS G130 Engineering Manual

SINAMICS S120
Engineering Information

6.9 Maximum connectable motor cable lengths

6.9.1

Booksize units

The Motor Modules generate an AC voltage to supply the connected motor from the DC link voltage. Capacitive
leakage currents are generated in pulsed operation and these limit the permissible length of the motor cable.
The following maximum motor cable lengths have to be taken into account:
Line supply Output power
voltage
Without reactor or filter
380 V – 480 V 1.6 kW – 4.8 kW
3AC 9.7 kW
16 kW – 107 kW
2*1.6 kW – 2*4.8 kW
2*9.7 kW
Permissible motor cable lengths as standard for SINAMICS S120 Motor Modules in Booksize format
Where a longer motor cable is required, a higher power rating of the Motor Module must be selected or the
permissible continuous output current I
The data for Booksize format Motor Modules are given in the following table:
Length of motor cable (shielded)
Rated output > 50 m to 100 m
current
3 A / 5 A
9 A
18 A
I
I
contin.
30 A
45 A / 60 A
85 A / 132 A
200 A
Permissible motor cable lengths with over-dimensioning for SINAMICS S120 Motor Modules in Booksize format
The permissible cable length for an unshielded motor cable is 150 % of the length for a shielded motor cable.
Motor reactors can also be used on motors operating in vector and V/f control modes to allow the use of longer motor
cables. Motor reactors limit the rate-of-rise and magnitude of the capacitive leakage currents, thereby allowing longer
motor cables to be used. The motor reactor and motor cable capacitance form an oscillating circuit which must not be
excited by the pulse pattern of the output voltage. The resonant frequency of this oscillating circuit must therefore be
significantly higher than the pulse frequency. The longer the motor cable, the higher the cable capacitance and the
lower the resonant frequency. To provide a sufficient safety margin between this resonant frequency and the pulse
frequency, the maximum possible motor cable length is limited, even when several motor reactors are connected in
series.
SINAMICS Engineering Manual – November 2015
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Ó Siemens AG
Rated output
current
3 A – 9 A
18 A
30 A – 200 A
2*3 A – 2*9 A
2*18 A
must be reduced in relation to the rated output current I
continuous
> 100 m to 150 m
Use 9 A
Motor Module Motor Module
Use 18 A
Motor Module Motor Module
Use 30 A
Motor Module Motor Module
or
≤ 1.5 * I
max rated
≤ 0.95 * I
rated
Permissible I
max
I
contin.
Permissible I
max
I
contin.
Permissible I
max
I
contin.
Permissible I
max
I
contin.
Maximum permissible motor cable length
Type of Shielded cable
con-
struction
Single
Single
Single 100 m
Double
Double
> 150 m to 200 m
Use 9 A Not permissible
Use 18 A Not permissible
Use 30 A Not permissible
≤ 1.35 * I I ≤ 1.1 * I
rated max
≤ 0.9 * I I ≤ 0.85 * I
rated contin.
≤ 1.75 * I I ≤ 1.5 * I
rated max
≤ 0.9 * I I ≤ 0.85 * I
rated contin.
≤ 1.35 * I I ≤ 1.1 * I
rated max
≤ 0.95 * I I ≤ 0.9 * I
rated contin.
≤ 1.25 * I I ≤ 1.1 * I
rated max
≤ 0.95 * I I ≤ 0.9 * I
rated contin.
Unshielded cable
50 m 75 m
70 m 100 m
150 m
50 m 75 m
70 m 100 m
rated
> 200 m
Not permissible
Not permissible
Not permissible
Not permissible
rated
rated
Not permissible
rated
rated
Not permissible
rated
rated
Not permissible
rated
rated
.