GE Masoneilan 4700P Maintenance Manual

Also see for Masoneilan 4700E: Instruction manual

Contents

Masoneilan 4700P/E & 4800P/E Positioners Manual =| 49© 2015 General Electric Company. All rights reserved.Cam Lobe ChangeIf it is necessary to change the cam lobe only (without changing actuator action or positioner ac-tion) then proceed as follows:NOTE Do not disturb cam holder (36) setting on rotary actuators. [i.e. donot touch set screws (35)].CAUTION If cam is not at low signal line on lobe (low end of range), do notattempt to remove cam. The cam must be at low signal line. Selectcorrect actuator and positioner action and proceed as follows.Air to Open / Direct Acting PositionerSee Figure 19 on page 68 and Figure 20 on page 71.1. Shut off supply pressure and signal to positioner. Valve is now closed and cam (26)is at low signal line on lobe.2. With cam at low signal line remove screw (28) and washer (27). Note the relativeposition of the cam lobe being changed and then remove the cam (26).3. Select the desired cam lobe and replace cam (26) on cam shaft with low signal lineof desired lobe against cam follower. Ensure the newly selected cam lobe is in thesame relative position as the lobe noted in Step 2.4. Replace washer (27) and screw (28). Turn on supply pressure and signal topositioner. Check zero and span adjustment. Refer to “Zero Adjustment” onpage 48 and “Span Adjustment” on page 48.Air to Open / Reverse Acting PositionerSee Figure 19 on page 68.1. Shut off supply pressure and signal to positioner. Valve is now closed and cam (26)is at high signal line on lobe. Do not remove.2. Run an independent regulated air line to the valve actuator in place of positioneroutput line. Slowly apply proper air pressure through the regulator to open thevalve. Do not exceed designated supply pressure. (Handwheel may be used toopen the valve in place of regulated air line). Align the travel indicator with theopen end of travel scale. Do not over travel. Cam is now at low signal line on lobe.3. With cam at low signal line remove screw (28) and washer (27). Note the relativeposition of the cam lobe being changed and then remove the cam (26).