Owner's manual

ManualsBrandsRosemount ManualsOtherHAGAN 4 x 5 Torque Type Power Positioner-Rev J

SECTION III. REVERSE OPERATION

3-1. OPERATIONAL DESCRIPTION.

In reverse

action positioners, piston and piston rod movement

react opposite as direct acting positioners (Figure

l-2). An inverse cam is installed and supply air hoses

to the cylinder are reversed. ‘Ihe switched hoses cause

supply air to pressurize below piston for increasing

signal air pressures and above piston for decreasing

signal air pressures. In this case, piston movement is

inversely related to the signal. A falling input signal

pressure causes piston to raise and an increasing input

signal pressure lowers piston.

3-2. PROCEDURES FOR REVERSING OPERATION.

To reverse power positioner operation, refer to Figure

3-1 and use the following procedures.

a. Reversing Action Procedure.

WARNING

Before performing any maintenance,

adjustment, or repair action cm power

positioner, shut off supply air, signal air,

and any electrical supply or electronic

signals to power positioner. Isolate power

positioner from all systems connected to the

power positioner. Severe injury or death

may result from large torque power

positioner is capable of producing, or from

electrical shock.

1. Remove power positioner from service.

2. Disconnect increasing signal supply air hose

from 90” elbow (3, Figure 3-1) at top of

cylinder (4).

3. Disconnect decreasing signal supply air hose

from 90’ elbow (3) at bottom of cylinder (4)

and connect to 90” elbow at top of cylinder.

4. Connect increasing signal supply air hose (1)

to lower cylinder 90” elbow (3).

5. Remove lock screw (5). adjustment screw

(6) and washers (7) securing cam (8) to cam

huh (9). Remove cam from hub.

6. Open bypass valve (10).

7. Using manual lever, position piston (11) at

bottom of cylinder (4). Piston will lx at

bottom of cylinder when clevis head is at

lowest pint.

8. Install inverse cam (8) on cam hub (9).

Align cam so adjustment screw hole is in

center of adjustment slot. Secure inverse

cam to cam hub with lock screw (5),

adjustment screw (6) and washers (7).

9. Lwsen socket head cap screws (12) securing

cam hub (9) to shaft assembly (13).

10. Adjust cam hub (9) so compensator lever

roller (14) is in pocket of inverse cam. Tbii

point is cam’s zero position.

11. Tighten socket head cap screws (12)

securing position of cam huh (9) on shaft

assembly (13).

12. Loosen lock screw (5) and adjustment screw

(6) searing cam (8) to cam hub (9).

13. Make minor adjustments to position of cam

(8) and zero compensator roller. Make sore

roller is perfectly aligned to zero point on

cam.

b. Calibrate Stroke. This procedure is to be used

only for power positioners with an inverse acting