Limitorque L120-85 Installation, Operation and Maintenance FCD LMENIM1202-03-A4 – 06/15
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The OPEN Rotor consists of contacts 1 through 4. These switches are set to change state at the full OPEN position. The switch functions are
as follows:
Contact 1
is the CLOSED Torque Switch bypass circuit. It’s purpose is to allow the electric actuator to apply its full torque to unseat a
backseated valve. When a valve is manually backseated to prevent packing leakage, it may stick momentarily when first operated. To prevent
the CLOSE Torque Switch from stopping the actuator during unseating, this momentary bypass is applied. The OPEN Rotor actuates at the
full OPEN position causing contact 1 to open as soon as the valve moves in the close direction, thus returning the Torque Switch function to
the control circuit.
Contact 2
is normally used for a Remote Valve Position Indication Lamp. As shown in Figure 8, the lamp will be turned ON when the valve
reaches the full OPEN position.
Contact 3
is for the Local Position Indication Lamp; included as part of the actuator assembly when required. This switch turns the green
lamp/LED OFF in the full OPEN position, leaving the red lamp/LED energized and indicating that the valve is OPEN.
Contact 4
is the OPEN Limit Switch which opens the control circuit to de-energize the Motor at full OPEN position.
The CLOSE Rotor consists of contacts 5 through 8. This Rotor is set to change state at the full CLOSE position. Switch functions are as
follows:
Contact 5
is the OPEN Torque Switch bypass. After the valve has been tightly closed, it may stick when it is first opened which would cause
the Torque Switch Contacts to break. To momentarily overcome this sticking, the OPEN Torque Switch is bypassed. This OPEN Torque
Switch bypass is part of the closed valve position rotor so that as soon as the valve moves in the OPEN direction, the bypass contact opens
and the OPEN Torque Switch control function is returned.
Contact 6
is normally used for a Remote Valve Position Indication Lamp. As shown in Figure 8, the lamp will be turned ON when the valve
reaches the full CLOSE position.
Contact 7
is for the Local Position Indication Lamp; included as part of the actuator assembly when required. This switch turns the red
lamp/LED OFF in the full CLOSE position, leaving the green lamp/LED energized and indicating the valve is in the full CLOSE position.
Contact 8
is the CLOSE Limit Switch that opens the control circuit to de-energize the Motor at full CLOSE position.
4.3.2 Adjustment—General
Tools required:
• The cross-slotted Intermediate Shafts A, B, C and D have been designed for use with a 6” No. 2 Phillips screw driver shank chucked into a
variable speed reversible electric drill. (See figure 9 for Limit Switch components).
• Phillips Head or Flat Head screwdriver.
c
WARNING:
Potential Explosion Hazard. Do not use an electric drill for setting the Limit Switch in an explosive environment.
a
CAUTION:
When setting Limit Switch Rotor Cams using a variable speed reversible electric drill, Do Not run drill at speeds higher
than 200 RPM. Operating drill at high speeds can cause damage to gearing within the Limit Switch.