Rockwell Automation MPAR Electric Cylinders - Manual (Page 6)

6 MP-Series Electric Cylinders
Rockwell Automation Publication MPAR-IN001D-EN-P - September 2012
• Motor feedback, auxiliary feedback, and I/O connector kits are not included, but can be
purchased separately.
• Factory manufactured feedback and power cables are available in standard cable lengths.
They provide environmental sealing and shield termination. Contact your Allen-Bradley
sales office or refer to the selection guide for cables.
Electric Cylinders with Brake Option
The brake option on this servo motor is a spring-set holding brake that releases when voltage is
applied to the brake coil. A separate power source is required to disengage the brake. This power
source can be applied by a servo motor controller or manual operator control.
If system main power fails, holding brakes can withstand occasional use as stopping brakes.
However, this creates rotational mechanical backlash that is potentially damaging to the system,
increases brake wear, and reduces brake life.
An unpowered electric cylinder will require a brake to maintain its position if the force on the
actuator exceeds the Back Drive Force listed in Kinetix Linear Motion Specifications Technical
Data, publication
GMC-TD002.
A brake can be use with the actuator to keep it from backdriving, typically in vertical
applications. A brake may be used for safety reasons or for energy savings allowing the actuator to
hold position when unpowered.
IMPORTANT Holding brakes are not designed to stop rotation of the motor shaft, nor are they intended to be
used as a safety device. They are designed to hold a motor shaft at 0 rpm for up to the rated
brake holding torque.
The recommended method of preventing motor shaft rotation is a four step process: first,
command the servo drive to 0 rpm; second, verify the motor is at 0 rpm; third, engage the
brake; and fourth, disable the drive.
Disabling the drive removes the potential for brake wear caused by a badly-tuned servo system
oscillating the shaft.