The electric capacity control actuator is an accessory that is available on simplex and duplex mRoy A and B pumps. For
both models, the actuator mounts directly to the pump drive housing in place of the conventional micrometer capacity
adjusting knob. Figure 1 shows actuator assemblies mounted on the pumps. The actuator is attached to (and positions)
the pump capacity control spool. Although both assemblies are the same size, spool coupling hardware and the pulley
ratio for positioning the feedback potentiometer differ (see Figures 3 and 4). Details are noted in Figure 6.
The actuator adjusts and maintains pump delivery by responding to a forward, off, or reverse signal received from a
controlling instrument. The components are connected as shown in the functional block diagram (Figure 2). Milton Roy
offers five standard controllers with a variety of manual and automatic control options, as described on the following
page. Actuator-controller wiring interconnection details are shown in Figures 7, 8, 9, 10. and 11; actuator installation
dimensions are shown in Figure 12.
Figure 2. Operating Principle Block Diagram