Flowserve SMB Series Electric Actuators - Manual (Page 15)

15
SMB Series/SB Series Installation and Maintenance FCD LMENIM1401-04-AQ – 01/15
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4.4.1 Two-Train Geared Limit Switch
The rotor-type, two-train geared limit switch employs two rotors. Each rotors contains four contacts.
When the rotor is properly set to trip at the desired position, two of these contacts open electric
circuits and two of the contacts close electric circuits. One rotor is normally set to trip at the full open
position of the valve, and the other rotor is normally set to trip at the full close position of the valve.
Each rotor may be adjusted independently of the other:
• First rotor—one circuit is used to open the “open” holding coil circuit of the motor controller, one
circuit is used to control the “open” indicating light.
• Second rotor—one circuit is used to open the “close” holding coil circuit of the motor controller,
one circuit is used to control the “closed” indicating light.
For the geared limit switches to trip at any desired position, follow the setting procedure below.
Piece numbers refer to Figure 4.2 and Table 4.4.
1. Verify all power is OFF.
2. Using the handwheel, manually open the valve to the full open position. See Section 5.2 Manual
Operation. Note the direction of rotation of the Intermittent Gear Shaft (piece #42), located over
the Rotor (piece #49) to be set.
3. Using a screwdriver, turn the Set Rod (piece #48) clockwise until it reaches a stop position.
4. If the Rotor (piece #49) you are setting has not turned 90° to open the contacts that should trip
open at this position, insert screwdriver on the Intermittent Gear Shaft (piece #42). Turn in the
direction noted in Step No. 4 until the Rotor (piece #49) turns and opens the contacts to be set.
5. If the Rotor (piece #49) has turned so that the contacts are already open, turn the Intermittent
Gear Shaft (piece #42) in the opposite direction as previously noted in Step No. 4 until the
contacts close. Turn the Intermittent Gear Shaft (piece #42) slightly in the direction noted in Step
No. 4 until the contacts open. The Rotor (piece #49) is set at the correct position for contact
opening.
Note: In the contact “Close” position, ensure a gap exists between the contact finger and the
L-bracket as seen in figure 4.2
6. Back off the Set Rod (piece #48) until it stops. Place the screwdriver on the Intermittent Gear
Shaft (piece #42) to ensure that the shaft is tight and will not rotate. Do not force.
7. Close the valve completely. Repeat Step No. 1 through 6 to set the tripping position for the other
Rotor (piece #49).