Siemens SINAMICS S150 - Maximum Connectable Motor Cable Lengths; Booksize Units

SINAMICS S120
Engineering Information
SINAMICS Engineering Manual – November 2015
Ó Siemens AG
378/528
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:
Maximum permissible motor cable length
Line supply
voltage
Output power Rated output
current
Type of
con-
struction
Shielded cable Unshielded cable
Without reactor or filter
380 V – 480 V 1.6 kW – 4.8 kW 3 A – 9 A Single 50 m 75 m
3AC 9.7 kW 18 A Single 70 m 100 m
16 kW – 107 kW 30 A – 200 A Single 100 m 150 m
2*1.6 kW – 2*4.8 kW 2*3 A – 2*9 A Double 50 m 75 m
2*9.7 kW 2*18 A Double 70 m 100 m
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
continuous
must be reduced in relation to the rated output current I
rated
.
The data for Booksize format Motor Modules are given in the following table:
Length of motor cable (shielded)
Rated output
current
> 50 m to 100 m > 100 m to 150 m > 150 m to 200 m > 200 m
3 A / 5 A Use 9 A
Motor Module
Use 9 A
Motor Module
Not permissible Not permissible
9 A Use 18 A
Motor Module
Use 18 A
Motor Module
Not permissible Not permissible
18 A Use 30 A
Motor Module
or
I
max
≤ 1.5 * I
rated
I
contin.
≤ 0.95 * I
rated
Use 30 A
Motor Module
Not permissible Not permissible
30 A Permissible
I
max
≤ 1.35 * I
rated
I
contin.
≤ 0.9 * I
rated
I
max
≤ 1.1 * I
rated
I
contin.
≤ 0.85 * I
rated
Not permissible
45 A / 60 A Permissible
I
max
≤ 1.75 * I
rated
I
contin.
≤ 0.9 * I
rated
I
max
≤ 1.5 * I
rated
I
contin.
≤ 0.85 * I
rated
Not permissible
85 A / 132 A Permissible
I
max
≤ 1.35 * I
rated
I
contin.
≤ 0.95 * I
rated
I
max
≤ 1.1 * I
rated
I
contin.
≤ 0.9 * I
rated
Not permissible
200 A Permissible
I
max
≤ 1.25 * I
rated
I
contin.
≤ 0.95 * I
rated
I
max
≤ 1.1 * I
rated
I
contin.
≤ 0.9 * I
rated
Not permissible
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.