
8.2 Racking to 'full in' or 'full out' Limits
The MDSR1 electronically limits the amount torque
that is applied to the racking mechanism. By
observing the torque bargraph on the right side of the
video display, the operator should notice an increase
in torque as the breaker stabs are engaging the
switchgear bus, as well as when the breaker is racked
to either extreme limit (racked in or racked out).
Anytime the racking motor drives to a stalled
condition, the control system will stop the motor and
then reverse direction to back-off the racking
mechanism by approximately 1/2 turn of the racking
mechanism -- provided both, the Enable button and
Racking rocker switch are held. The video display will
then indicate "Complete".
Additionally, the racking motor is equipped with a
stall-sensor to sense motor stall. DO NOT be hesitant
to run the racking motor to 'full stall' in either
direction. To protect the racking motor, the control
system limits the amount of time the motor can
remain in a stalled condition, as well as limiting the
motor current to a safe level.
9.0 Sequence of Operation:
Connect the control cable to the power supply and
handheld control unit. 4.1
If AC power is used, test the GFCI. 4.2
Power-up the power supply by turning toggle switch
ON. The green 'DC' light should illuminate. If the
unit is plugged into AC power, the red 'AC' should
illuminate too. The cooling fan should be running.
If the yellow 'Low DC' light comes on, plug the unit
into an AC power source.
7.0
Observe the screen on the handheld controller.
Press the Enable button to acknowledge you have
read the warnings and to advance to the next
screen.
6.0
Install the racking head. 8.0
Standing outside the arc-flash boundary zone,
depress the Enable button while simultaneously
depressing the Racking rocker switch in the desired
direction, i.e. Rack IN or Rack OUT.
6.0
Observe the video display to monitor the breaker
position indicator as well as the torque that is being
applied. 6.3
Release either, the Enable button or the Racking
rocker switch to stop the racking motor at any time. 6.0
If the Enable button and Racking rocker switch are
held continuously, once the motor drives to a
stalled condition, it will automatically stop, and
reverse directions until the racking nut (socket)
turns approximately 1/2 turn. The display will then
say "Complete".
8.2
Steps
See
Section