Rockwell Automation M3575RH Series Instruction Manual

Snubber Braking Kits for AC Drives
Enclosed Resistor Modules, Enclosed Transistor Modules
M3575RH__, M3575RL__, M3575TH__, M3575TL__
ATTENTION: Only qualified electrical personnel familiar with the construction and operation of
this equipment and the hazards involved should install, adjust, operate, and/or service this
!
equipment. Read and understand this manual and other applicable manuals in their entirety
before proceeding. Failure to observe this precaution could result in severe bodily injury or loss
of life.
Product Description
Snubber Braking kits connect to 230 VAC and 460 VAC GV3000/SE, SP120, SP500, and VSM500 drives.
These kits dissipate the power regenerated by the motor during rapid deceleration or during overhauling load
conditions.
The regenerated energy is normally consumed, as shown in figure 1, by mechanical loss, by the motor, and by
the drive. The remaining energy is stored in the drive's DC bus capacitor. If the remaining energy causes the
capacitor voltage to rise above the normal operating range, the Braking Unit will discharge the regenerated
energy before the drive voltage becomes excessive.
Energy
Regenerated
by the Motor
Consumption
by Mechanical
Loss
Power resistors are used to dissipate the energy. When the DC bus voltage rises above normal level, either a
built-in transistor (in GV3000/SE bookshelf drives) or an external transistor (used with NEMA-type GV3000/SE,
SP500, and VSM500 drives) automatically switches the dynamic braking resistors on in
pulse-width-modulation (PWM) mode to absorb the excess energy. The transistor is turned fully on at 375 VDC
for 230 VAC input drives and at 750 VDC for 460 VAC input drives. The snubber resistors are sized to provide
the power dissipating capability required for the duty cycle of the application.
Snubber Braking Kits for AC Drives
Model Numbers
Instruction Manual D2-3439-1
Consumption
in the Motor
Itself (approx.
10 to 20% of
Output
Figure 1 – Dissipation of Energy Regenerated by the Motor
Consumption Storage in
by the Drive Capacitor of
Itself the Drive
Discharge of
Regenerated
Energy at
Braking Unit
1