Rockwell Automation SP600 AC Drive User Manual Version 1.0 - Manual (Page 79)

Installing Power Wiring 6-9
6.4 Dynamic Braking Connections
A dynamic brake consists of the 7th internal braking transistor and
an optional dynamic brake resistor. Reference “SP600 AC Drive
Dynamic Braking Guide,” manual number D2-3489, for a more
detailed discussion of dynamic braking.
The internal dynamic braking circuit senses rising DC bus voltage
and shunts the excess energy to the dynamic brake resistor. The
7th transistor is either ON or OFF, connecting the dynamic brake
resistor to the DC bus, or isolating the resistor from the DC bus. It is
important to properly size the braking resistor value. To determine
the minimum resistance value possible based on drive rating, see
table 6.3.
Note that the resistor wattage is application-dependent and should
be sized to inertia, deceleration, and duty cycle requirements.
Figure 6.7 shows a simplified dynamic braking schematic.
Figure 6.7 – Simplified Dynamic Braking Schematic
BR1
BR2
+DC Bus
-DC Bus
Dynamic Braking
Resistor
Chopper
Transistor
Chopper Transistor
Voltage Control
To Voltage Dividers
*
*
*BR1 and BR2 are the connection points
on the terminal block for braking resistors. These
terminals may be labeled DC+ and BRK on
earlier drive models.