Dimensioning Of Braking Resistors - Siemens SINAMICS S120 Configuration Manual

6.4.4

Dimensioning of braking resistors

The correct dimensioning ensures an optimum braking time. The braking torques which are
obtained are also listed in the tables. These data apply to braking operations from the rated
speed and moment of inertia J
the braking time cannot be proportionally reduced. However, longer braking times cannot
occur if the speed at the start of braking is less than the rated speed.
The data in the following table is calculated for rated values according to the data sheet.
The variance during production as well as iron saturation have not been taken into account
here. Higher currents and torques can occur than those calculated as a result of the
saturation.
Table 6-15 Dynamic braking for 1FK7 CT
Motor type Braking
resistor,
external
R
1FK7011-5AK71 2.3
1FK7015-5AK71 6.2
1FK7022-5AK71 4.1
1FK7032-5AK71 15.7
1FK7034-5AK71 12.7
1FK7040-5AK71 20.1
1FK7042-5AF71 16.4
1FK7042-5AK71 9.0
1FK7060-5AF71 8.8
1FK7060-5AH71 6.9
1FK7063-5AF71 4.8
1FK7063-5AH71 3.4
1FK7080-5AF71 10.0
1FK7080-5AH71 6.7
1FK7083-5AF71 3.6
1FK7083-5AH71 3.0
1FK7100-5AF71 4.1
1FK7101-5AF71 2.1
1FK7103-5AF71 1.4
1FK7105-5AC71 1.8
1FK7105-5AF71 1.2
Synchronous Motors 1FK7
Configuration Manual, (PFK7S), Edition 12.2006, 6SN1197-0AD16-0BP1
Average braking torque
M [Nm]
br rms
Without
[Ω]
opt
external
braking
resistor
0.13
0.23
1.0
0.7
1.3
0.4
1.3
0.9
1.8
1.5
3.3
2.5
2.0
1.5
4.9
2.8
4.1
5.6
7.3
15.2
11.9
6.4 Brake resistances (armature short-circuit braking)
= J . If the drive is braked from another speed, then
external mot
Max. braking
torque M
[Nm]
With external
braking
resistor
0.14 0.17
0.28 0.35
1.2 1.5
1.1 1.4
2.0 2.5
0.9 1.1
2.2 2.7
2.2 2.7
4.0 5.0
4.1 5.2
8.2 10.2
7.9 9.8
5.5 6.8
5.6 6.9
13.7 17.0
12.5 15.5
13.2 16.4
20.6 25.7
28.3 35.1
44.5 55.3
45.9 57.0
Motor components
RMS braking current
I [A]
br max
br rms
Without
external
braking
resistor
2.5
2.6
5.9
3.7
5.5
3.2
3.6
7.5
7.2
10.3
14.0
20.5
8.1
12.3
21.2
28.0
19.6
34.4
49.4
44.2
68.9
With external
braking
resistor
2.3
2.3
5.4
3.4
4.9
2.9
3.2
6.7
6.4
9.2
12.5
18.3
7.2
11.0
19.0
25.0
17.5
30.8
44.2
39.6
61.6
87