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Drive set-up

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					Drive set-up
Basic drive set-up and span position limit switch points
      The following is a guideline for setting the variable drives and limit
switches. These set points are intended for a starting point and not an absolute.

Thyristor drives
      1. The drives are normally set for a 25% slip with the secondary resistor
         bank
      2. The full or 100% speed should be at 75% of the full synchronous of the
         motor, as an example this would be 675rpm of a 900 rpm motor
      3. The reduced or 50% speed should be at 37.5% of the full synchronous of
         the motor, as an example cases this would be 337 rpm of a 900 rpm
         motor
      4. The creep speed or seating speed should be based on the speed at which
         the span needs to seat, (the softer the batter) , in many cases this would
         be 120 rpm, of a 900 rpm motor.
      5. The reduced toque or reduce current during the seating sequence should
         be less the 100% of the motor F.L.A.
      6. The ramp time should be set at 10 seconds (full ramp available). The full
         ramp time will aid in minimizing the large start-up current draw.
      7. Speed control should be set soft to allow the span to float in speed. This
         will prevent large surges of current during span motion. There will be
         large current surges during the start of the span motion.
Limit switch set points
      1. Low speed check points should be set as to allow for an emergency stop
         of the span without hitting the full open or full close stop. This point
         should check to see that the span is slowing done, from the slowest run
         speed to seating speed. (One half of the reduced, 50% speed, or 25%
         speed 160r.p.m.)
      2. High speed monitoring should be set to stop span before a speed is
         reached that will cause damage. This point is normally set at 110% of full
         speed ( a round number of 750 rpm is normally used )
      3. The near open and near close deceleration points should be set to allow
         the span to decelerate below the speed check reference rpm.
      4. The near open and near close pilot lights should be set to the same points
         as the decelerate points.
      5. The full open point should be set to allow the span to clear the pier
         without hitting the full open bumper stop. The switch should be set in the
         opening direction only.
      6. The full close or seated switch should be set when the span is moving in
         the seating direction only.

				
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posted:5/5/2011
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