Dimensioning Of The Construction Of Braking Resistors - Siemens SIMOTICS S-1FK2 Configuration Manual

Figure 5-6
5.4.2

Dimensioning of the construction of braking resistors

Rating
NOTICE
Destruction of the braking resistors
Braking from the rated speed is not permitted any more frequently than every 2 minutes;
otherwise the resistors will be destroyed.
• Maintain a time interval of at least 2 minutes or longer between braking operations.
• When required, specify other braking cycles when ordering.
You can dimension the braking resistor so that a surface temperature of 300 °C can occur briefly
(max. 500 ms).
The external moment of inertia and the intrinsic motor moment of inertia are decisive when
dimensioning the braking resistors.
When ordering the braking resistors, determine the kinetic energy involved.
Kinetic energy W = ( ω
Angular velocity ω = ( 2 • π / 60 ) • n
Coordinate the braking resistor ratings to the I
1FK2 Synchronous Motors for SINAMICS S120
Configuration Manual, 02/2022, A5E46927724B AD
Circuit (schematic) with brake resistors
• J ) / 2 W / Ws = kinetic energy
2
J / kgm
ω / 1/s = angular velocity
n / r/min = speed
5.4 Brake resistances (armature short-circuit braking)
= moment of inertia
2
t load capability.
2
Configuration
75