SMI21
30
9.1.1.1.
Proposed Ballast Circuit Diagram
The diagram below allows the braking energy to be dissipated into a resistor, thus limiting voltage surges at
the motor terminals.
Figure
5
9.1.1.2.
Determining the Size of the R12 Resistor (R
Ballast
)
The higher the braking current, the lower the resistor value. Typical values are around several Ohms.
With V the rotation speed in revolutions per minute and J the inertia in Kg.m², the energy E in Joules stored
in the inertia is given by: