Rockwell Automation MPL-xxxx Low-inertia Servo Motors 75 mm or Smaller - Manual (Page 8)

8 MP-Series Low-inertia Brushless Servo Motors with 75 mm or Smaller Frame Sizes
Rockwell Automation Publication MP-IN006C-EN-P - January 2014
Power Cable Shielding
Brake Control and Power Regulation
The DC power source for a permanent magnet brake, such as that on the MP-Series servo motor
with 75 mm (2.95 in.) or smaller frame, requires a DC power supply with low ripple voltage.
A motor brake requires relay contacts to open and remove power to the brake coil. Removing
power causes the brake to mechanically engage, but it also can cause electrical arcing to occur at
the contacts until the residual brake power sufficiently dissipates. A customer supplied diode is
recommended to prevent electrical arcing at the brake relay contacts. Substituting a metal oxide
varistor (MOV) for the diode can reduce the time to mechanically engage the brake. The
following diagram shows typical customer supplied components for brake control, including an
arc suppressing diode or MOV.
Arc Suppression in the Motor Brake Circuit
The Kinetix 6000 drive from Rockwell Automation has a brake control relay that includes a
MOV arc suppressor. Customer-supplied arc suppression is not required in this case, unless
power consumption by the brake requires an external brake relay.
Shielded Signal Wires (two) within Power Cable
Overall Power Cable Shield
Loop signal shield (one of two) to overall
power cable shield.
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Factory Supplied
Field Modified
Verift that the power cable ground clamp on the drive
contacts all (three) cable shields.
BR+
BR-
+
-
DC Power
Supply
Customer
Supplied
Components
Brake Relay
Diode or MOV Arc Suppressor