Section 5: Multi-Turn Actuators; Calibration - Emerson EIM E796 M2CP Installation And Maintenance Manual

Section 5: Multi-turn Actuators

August 2017
Section 5: Multi-turn Actuators
Multi-turn top-mounted and side-mount bevel gear actuators require use of Gear
Reduction Assembly part no. 84055-0000 for Mechanical Dial Position Indication MDPI and
1-turn Pot. N-number replaces -0000 to complete part no. For 1-turn Pot only without Dial
Indication part no. is 84117-0000. Refer to EIM JOB SPEC SHEET for MDPI furnished.
MDPI Mechanical Dial Position Indication is a gear reduction assembly to convert multi-turn
valve stem nut turns to 270 degrees (.75 turn) for viewing position indication arrow thru
glass window on actuator electric switch compartment cover. Point of rotation reference
has been designated as N-number. N is the total number of electric actuator 12-tooth gear
limit spring-load pinion rotations for full valve stroke.
Figure 11
5.1

Calibration

MDPI & POT Drive is calibrated after LSC and LSO are properly set (Pg. 4). Move valve to
Close position. Manually rotate MDPI arrow to indicate Close. Calibration is now complete.
Open valve to check that MDPI arrow goes to Open, indicating that N is correct for full
valve travel. Potentiometer, if included, has been calibrated. Mechanical dial travel is 270°.
Approximately 5% of total Pot resistance is left on each end for total valve travel.
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Installation and Maintenance Manual
E2K-402-0817 Rev. 2
Multi-turn Actuators