Siemens SIMOTICS S-1FT7 User Manual

Configuration
5.4 Brake resistances (armature short-circuit braking)
S-1FT7 synchronous motors
124 Configuration Manual, 09/2018, A5E45099423B AA
5.4.2
Dimensioning of braking resistors
Correct dimensioning of the braking resistors determines the optimum braking time.
The braking torques that are obtained are listed in the tables. The data applies for braking
from the rated speed and moment of inertia J
external
= J
Mot
.
If you brake the drive from another speed, the braking time cannot simply be reduced
proportionally.
In this case, calculate the braking time using the formula provided in Chapter "Description of
function braking resistor (Page 120)".
If the speed at the start of braking is less than the rated speed, the braking times will be
shorter or remain the same.
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 considered. Due to
saturation, currents and torques can be higher than calculated.
1FT7 Compact, natural cooling
Table 5- 3 Armature short-circuit braking with/without external braking resistors
Motor type
External brak-
ing resistor
R
opt
/ Ω
Average braking torque M
Br rms
/
Nm
Max. braking
torque M
Br max
/
Nm
rms braking current I
br rms
[A]
Without external
braking resistor
With external
braking resis-
tor
Without exter-
nal braking
resistor
With external
braking resis-
tor
1FT7034-☐AK7
6.7
2
3
4
9
8
1FT7036-☐AF7
4.2
3
5
6
15
14
1FT7042-☐AF7 6.6 3 4 5 7 7
1FT7042-☐AK7
5.0
2
4
6
14
12
1FT7044-☐AF7
4.8
7
10
12
13
12
1FT7044-☐AK7
3.3
5
10
12
25
22
1FT7046-☐AF7
3.6
10
14
17
18
17
1FT7046-☐AH7
1.6
8
14
17
36
32
1FT7062-☐AF7
10.4
2
4
5
7
6
1FT7062-☐AK7
5.0
1
4
5
15
13
1FT7064-☐AF7
7.0
3
7
9
11
10
1FT7064-☐AK7
6.1
2
7
9
17
15
1FT7066-☐AF7
3.8
4
11
13
18
16
1FT7066-☐AH7
2.5
3
10
13
27
24
1FT7068-☐AF7
4.5
6
15
18
20
18
1FT7082-☐AC7
9.6
4
9
11
8
8
1FT7082-☐AF7
6.7
3
9
11
13
11
1FT7082-☐AH7
3.9
2
9
11
21
19
1FT7084-☐AC7
3.9
7
16
20
18
16
1FT7084-☐AF7
4.4
5
16
20
21
19

Siemens SIMOTICS S-1FT7 Specifications

General

Brand	Siemens
Model	SIMOTICS S-1FT7
Category	Engine
Language	English