Installation Manual

ValveWatch II Hardware Installation and Setup Manual
Page 26 of 34
CRANE
Nuclear
8.2 Pre Installation Strain Sensor Test
• Perform a visual inspection of the sensor. Make sure that it does not have any physical
damage to the sensor mounting face or cable.
• Verify that the cable has not been damaged; there should be 50 feet of cable integral to the
sensor.
• The sensor may be checked for electrical continuity with an ohmmeter by measuring 5000
ohms between the yellow and green wire pair as well as the brown and white wire pair. All
resistances should read infinity between any insulated conductor and both the sensor metal
housing or the cable shield. The cable shield and sensor housing are not electrically connected
and should also read infinity.
• The strain sensor assembly is factory tested to assure 500 volt isolation from ground. No
special installation process is required to assure ground isolation.
8.3 Strain Sensor Mounting Locations
• Mount the strain sensor when the valve yoke is at or above 70°F (25°C). If the valve yoke
temperature is lower than this, an external heating supply such as a heat gun or heat trace
must be used.
• For high temperature applications and non-symmetric yoke designs, the preferred mounting
location is typically closer to the actuator than the valve body. This can be important for long
yokes where oscillations and/or bending may occur. The sensor may sense yoke bending
measurements as the actuator weight shifts at lower loads.
• The sensor was designed to be used for either torque or thrust. There are four mounting
orientations defined for torque and four mounting orientations defined for thrust. The main
reason for the four mounting locations of each is to identify the easiest sensor cable run to the
LDAU enclosure box. A simple rule of thumb is to use the cable angle of the sensor to
determine whether you are measuring torque or thrust. To measure torque, the cable exiting
the sensor will be at a 45 degree angle with the valve stem. To measure thrust, the cable angle
will be parallel or perpendicular with the valve stem. For a more detailed view of the
mounting positions for the sensor, refer to J-53115ExR for Strain Sensor Field Installation.
• Verify that the cable tie length is sufficient for supporting the sensor during epoxy cure time.
If there is not enough cable tie length, multiple cable ties may be connected together.
Caution:
The strain sensor’s Kapton mounting face is very sensitive to strain and exceptionally durable
when installed but can be damaged if handled roughly prior to installation. The Kapton face
mounting material also provides electrical insulation from earth ground. Do not remove the
protective cap except for inspection or in preparation for installation. Do not apply unnecessary
pressure or press on the sensor face during inspection or installation.