This listing describes the conversion of Lucas Machines equipped with older style 'ER' (Electronic Relay) speed sensing relays to a unit of a more modern design.
While the newer units are functionally equal to the older units and use many of the same component parts, the primary advantage gained by installing a new unit (instead of repairing the original) is in the machine tool reliability gained by replacing all of the 'aged' components at one time - rather than one piece at a time as they fail.
The newer units are physically smaller than the original units. The older 'ER' units were originally 'built up' on terminal strips with discrete components in a sheet metal enclosure of approximately 8 by 10 inchesThe new 'ER' unit is a printed circuit subassembly, of approximately 3 by 5 inches. This can be of value if you are making other panel changes and additional space becomes necessary.
Materials Required to Implement Conversion:
1 108769-C Printed Circuit Board, consisting of:
1 109779-C (4028-41-01) PC Board
1 910297 Relay
1 912088 Potentiometer
1 912320 Capacitor
1 911737 Resistor
1 912596 Rectifier Bridge
1 912647 Terminal Connector
1 910718 6 Inch Piece, Board Mounting Track
1 108769-C Blueprint ONLY
1 Copy, This Listing
INSTALLATION:
- Remove the existing unit, being certain that all wires are well marked with the appropriate wire numbers.
- Install the new, solid-state replacement unit. (Be certain that the mounting screws for the plastic track cannot contact the back of the printed circuit board of the new sensor assembly.)
- Connect 110-volt power to terminal (7) on the solid-state replacement unit.
- PLEASE NOTE that terminal (5) is 'skipped' on the new unit.
- Connect the (2) input wires from the tachometer to terminals (1) and (2) on the solid-state unit.
- Connect the contact of the new relay into the existing machine tool control circuit at the same location that the relay of the older unit was connected. Be careful to observe if the contact originally used was Normally-Open (N.O.) or Normally-Closed (N.C.) and wire the new relay the same way.
- The additional terminal connections of the new, solid-state unit are not used.
- Be certain that all wires are labeled, and that any unused wires are safely removed all the way back to the closest terminal point.
ADJUSTMENT:
- Select the SLOWEST Spindle Speed.
- Start and stop the Spindle Rotation several times and observe the reaction (during motor stop only) of the vertical splined drive shaft (the largest splined shaft) that carries rotational drive power to the machine headstock.
- Adjust the small control mounted on the new, solid-state unit so that the splined shaft stops without coasting or 'kick-back'. Please note that as spindle speed is increased, coasting of the shaft is normal.
