PROXIMITYTRANSDUCERSYSTEM OPERATION

CopyrightBently Nevada CorporationAll Rights Reserved, 1996

The following marks are Bently Nevada Corporation’s Registered Trade Names:

MicroPROX ADRE REBAMKeyphasor Proximitor SeismoprobeKey Velomitor TorXimitorTrendmaster Smart Monitor Data ManagerDynamic Data Manager Transient Data Manager Bently Nevada

OUTERSCREEN

CENTERCONDUCTOR

INNERSCREEN

INSULATION

TRIAXIAL CABLE

PROBE NUMBERING

CABLE FIXEDLOCK NUT

TIPASSEMBLY

P/N 330106-05-30-10-02-00

S/N APRS 416567

EXTENSION CABLE NUMBERING

HEAT SHRINK SLEEVING

CONNECTOR

P/N 330130-080-00-00

PROXIMITOR

SIGNAL OUTPUT

SIGNAL COMMON

TRANSDUCER POWER

ELECTRICAL LENGTH

PROXIMITOR OPERATION

<100mil

RF SIGNAL

EXTENSION CABLEAND PROBE

PROXIMITOR

DEMODULATOR

OSCILLATORBENTLY

NEVADA

CONDUCTIVE MATERIAL

EDDY CURRENTS

RF SIGNAL

BENTLY

NEVADA

EDDY CURRENT FLOW

R

RF SIGNAL

SMALL GAP

0

LARGE GAP

RF SIGNAL 0

RF SIGNAL

CHANGING GAP

0

DEMODULATOR OPERATION

DEMODULATOR INPUT

PROXIMITOR OUTPUT

0

0

RADIAL MOVEMENT

AXIAL MOVEMENT

RADIAL AND AXIAL MOVEMENT

NOTCH

GAPCHANGE

ONEREVOLUTION

TIME

VOLTAGE CHANGE

PROBE OVER SURFACE

PROBE OVERNOTCH

KEYPHASOR WITH NOTCH TARGET

BENTLY

NEVADA

VOLTAGE CHANGE

PROJECTION

TIME

ONEREVOLUTION

PROBE OVERPROJECTION

PROBE OVERSURFACE

KEYPHASOR WITH PROJECTION TARGET

GAPCHANGE

BE

NT

LY

NE

VA

DA

CH

AN

GE

IN

VO

LT

AG

E

CHANGE IN GAP

24O

UT

PU

T I

N V

OL

TS

- D

C

PROBE GAP

mils 00

10 20 30 40 50 60 70 80 90 100 110 120 130 140

2

4

6

8

10

12

14

16

18

20

22

PROXIMITOR CALIBRATION GRAPH

Average Scale Factor (ASF)

equals:

change in gap voltage

change in gap

(-18.0Vdc) - (-2.0Vdc)

0.08in or 2.0 mm

= 200 mV/mil

or

= 7.87 mV/um

-24V SUPPLY

POWER SUPPLY VOLTAGE EFFECTS

PROBE GAP

-16V SUPPLY

OU

TP

UT

IN

VO

LT

S -

DC

24

22

20

18

16

14

12

10

8

6

4

2

0

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140mils

COMPONENT MISMATCH EFFECTS

PROBE GAP

OU

TP

UT

IN

VO

LT

S -

DC

SHORT

CORRECT

LONG

24

22

20

18

16

14

12

10

8

6

4

2

0

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140mils

TARGET MATERIAL EFFECTSO

UT

PU

T I

N V

OL

TS

- D

C

PROBE GAP

4140 STEEL

TUNGSTEN

ALUMINUM

COPPER

24

22

20

18

16

14

12

10

8

6

4

2

0

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140mils

CROSSTALK

SIDEVIEW

TARGET SIZE

YES

NO

PROXIMITOR CALIBRATION EQUIPMENT SET-UP

PROXIMITOR CALIBRATION EQUIPMENT SET-UP

DC VOLTMETER

-VTINPUT

PROXIMITOREXTENSION CABLE

SPINDLE MICROMETER

TARGET

PROBE

BENTLY

NEVADA

out

comvt

Q1. The three parts of a proximity transducer system are:a. b. c.

Q2. The ruggedised coaxial cable used in the system has a center conductor and .

Q3. What is the electrical length of the following probe? 330106-05-30-05-02-00 .

Q4. What is the electrical length of the following extension cable? 330130-045-00-00 .

Q5. What is the total electrical length required by the following Proximitor? 330100-50-00 .

ProbeExtension cableProximitor

two screens

0.5M

4.5M

5.0M

APPLICATION EXERCISE

Q6. The Proximitor must be supplied with a dc voltage between ____________ and .

Q7. An field is created around the probe. It extends away from the face of the probe for linear range of at least .

Q8. When a conductive material is within range of the probe _____________ flow in the surface of that material.

Q9. A Proximitor must be calibrated to suit the it has as a target.

Q10. The dc output from the Proximitor will go more as the target moves closer to the probe.

Q11. A proximity system frequency response is from to and its output may contain an and a component.

-17.5 Vdc-26.0 Vdc

RF80 mils

eddy currents

material

positive

0Hz(dc) 10KHzac dc

APPLICATION EXERCISE

Q12. Name three applications for a proximity transducer system. a.

b.

c. _____________________

Q13. Calculate the scale factor (sf) from the following: 90mils = 18.5Vdc, 10mils = 2.25Vdc. Is it within tolerance?

Q14. Name three reasons why a proximity system could be out of tolerance.

a.

b.

c.

Thrust measurementVibration measurementKeyphasor

203mV/mil Yes, 1.5% error

Incorrect supply voltage

Mismatched components

Incorrect target material

APPLICATION EXERCISE