T-NC/16-S NO CONTACT TRANSDUCER
FUNCTION
Transducer T-NC/16/S is used for performing the following measurements:
DIFFERENTIAL EXPANSION (ex.Turbine), i.e. relative movement between the rotor and the
machine casing; the measurement is made by mounting the sensor integral with the
machinery casing in the spot corresponding to the thrust block of known characteristics
prepared on the rotor. The picked up signal should be sent to the CEMB T2 unit for
processing.
AXIAL POSITION, (ex. Turbine Shaft Position with respect to the Thrust Bearing), the
measurement is made by mounting the sensor of each transducer on the machinery casing,
axially facing a block either mounted or obtained on the rotor close to the thrust
bearing, in order to measure the wear on the bearing. The signals picked up should be
sent of the CEMB T3 units for processing.
ECCENTRICITY, (ex.Turbine Shaft), the measurement is made by mounting the sensor of the
transducer on the machinery casing, radially facing a ring mounted or obtained on the
rotor, in order to measure the eccentricity of the rotor at low speed; the signal
picked up should be sent of the CEMB T4 unit for processing.
COMPOSITION
The transducer consists of a field-mounted sensor T-NC/16 and converter box T-NC/S
outside the machinery.
PRINCIPLE OF OPERATION
The T-NC system generates a radio frequency field which is radiated by the sensor
surface.
When the reference surface facing the sensor is invested by such RF field, an eddy
current is generated on it. The energy required to generate such eddy current (which is
proportional to the distance between the reference surface and the sensor surface)
reduces, in proportion, the energy present in sensor. Such difference is then detected
by the converter.
The converter amplifies and processes this signal thus supplying a d.c. output voltage
proportional to the distance under consideration.
TECHNICAL CHARACTERISTICS
Composition : sensor, converter
Type of measurement : differential
Range of measurement : ± 2 mm
Range of application : Temperature (Sensor) = -20°C to +175°C
Sensitivity : 2.5 V/mm
Power supply : + 15÷24 Vdc; GND.
Connection : Connector MIL C-5015, series 3102/16, standard kit
Convert. casing material : Die-cast aluminium
Sensor casing material : Stainless steel
Weight of the converter : ~ 0.7 Kg
Weight of the sensor : ~ 0.2 Kg
Maintenance : None
Drawings enclosed : 17281 = Overall dimensions, mounting, connections.
Temperature (Converter) = -10°C to +70°C
Humidity (Sensor) = max 100%
Humidity (Converter) = max95% with condens
Ambient (Sensor) = IP67 EN 60529/10.91
Ambient (Converter) = IP65 EN 60529/10.91
2
3
TRANSDUCER POSITIONING
ASTD54120
Refer to drawing Nr. 17281
1) Drill holes on the machinery for the sensor support and for any cable protection
devices (sheaths, ducts etc.).
2) Drill a hole to fasten the converter box at a distance from the machinery shorter
than that of the connecting cable (5m).
3) Separate the sensor from the converter by disconnecting the cable from the terminal
board inside the converter (carefully note the polarity of the two leads making up
the cable), then mount the sensor on the support prepared in point 1
4) After checking that the machinery lies in position K (ZERO position with the machine
stationary), perform a preliminary mechanical adjustment of the GAP by acting on
the nut-lock nut device of the sensor. The GAP indicated in the application drawing
refers to the mid point of the measuring range.
5) Fasten the converter box via the holes drilled in point 2, attach protective sheaths
if required, reconnect the sensor cable on the converter terminal board making sure
of the exact polarity of the two leads making up the cable.
6) Proceed to the electrical connection of the converter to the measuring instrument
as indicated in dwg. 17281.
POSITIONING FOR AXIAL POSITION
7A) With the machine in position K and with the measuring instrument operating, use
the nut-lock nut device of the sensor to search for the exact coincidence between
the mechanical gap and the electrical calibration of the converter in one or,
better, both of the following way:
- reading on a voltmeter connected across pins A and D of the converter connector
(or else across the terminals corresponding to the transducer signal input on
the terminal board of the instrument) on the scale 0 to 10 Vdc of the range of
measurement (0Vdc= scale start, 10Vdc=full scale) of the volts corresponding
to the Gap; as the Gap indicated in the application drawing of the transducers
refers to the mid point of the range of measurement, under this condition there
should be a corresponding reading of 5 Vdc.
Hence the sensor position should be adjusted through small displacements along its
longitudinal axis until the value of 5 Vdc on the voltmeter.
POSITIONING FOR ECCENTRICITY
7B) With the machine in position K and with the measuring instrument operating, use
the nut-lock nut device of the sensor to search for the exact coincidence between
the mechanical gap and the electrical calibration of the converter in the following
way:
- reading on a voltmeter connected across pins A and D of the converter connector
(or else across the terminals corresponding to the transducer signal input on
the terminal board of the instrument) on the scale 0 to 10 Vdc of the range of
measurement (0Vdc= scale start, 10Vdc=full scale) of the volts corresponding
to the Gap; as the Gap indicated in the application drawing of the transducers
refers to the mid point of the range of measurement, under this condition there
should be a corresponding reading of 5 Vdc.
Hence the sensor position should be adjusted through small displacements along its
longitudinal axis until the value of 5 Vdc on the voltmeter.
8) Then lock the sensor in position using the nut-lock nut device.
9) Close the converter making sure that it is spray- and dust-proof.
REMARKS REGARDING CORRECT POSITIONING OF TRANSDUCERS T-NC/S
1) Never, under any circumstances, modify the sensor / converter cable length: this
would cause a measuring error.
2) The end part of the sensor must lie at a distance from metal materials different
from the one involved in measuring the distance: at least twice the max. amplitude
of measurement (see application drawing).
3) When mounting the sensor, a reference cone should be prepared at 90° vertex from
the sensor tip. No metallic material must be introduced in the cone apart from the
surface to be measured.
UTS051020
4
Loading...