vibration manual

PART NO. 100076-01 Revision C 19 Dec. 95

VELOMITOR PIEZO - VELOCITY SENSOR

OPERATION MANUAL

Velomitor Operation Manual®

ii

Bently Nevada Corporation has attempted to identify areas of risk created by improper installationand/or operation of this product. These areas of information are noted as WARNING orCAUTION for your protection and for the safe and effective operation of this equipment. Read allinstructions before installing or operating this product. Pay particular attention to those areasdesignated by the following symbols.

CAUTION

A piezoelectric velocity transducer subjectedto a sudden mechanical impulse may generatea low frequency signal that does not representactual machinery vibration. This signal maychange the state of alarm and/or dangerrelays.

Velomitor is a registered trademark of Bently Nevada Corporation®

Proximitor is a registered trademark of Bently Nevada Corporation®

Doc. No. 100076 ## First Printing: June 1991

Copyright Bently Nevada Corporation 1991

All Rights Reserved

No part of this publication may be reproduced, transmitted, stored in a retrieval system or translated into anyhuman or computer language, in any form or by any means, electronic, mechanical, magnetic, optical,chemical, manual, or otherwise, without the prior written permission of the copyright owner,

Bently Nevada CorporationP.O. Box 157

Minden, Nevada 89423 USATelephone 800-227-5514 702-782-3611

Telex 354437Telemail 7400983 BNC UC

Fax 702-782-9253Copyright infringement is a serious matter under

United States of America and foreign copyright laws.


iii

Foreword

This manual describes the Bently Nevada Velomitor , a piezo-velocity sensor, and contains®

instructions for its installation and maintenance. If you need additional assistance contact thenearest Bently Nevada Corporation office.

This manual is intended for technicians and engineers experienced in the use of electronicinstrumentation and machinery monitoring equipment.

Section 1 describes the Velomitor , tells how it works, and lists applications and optional®

accessories. This section also includes information on the Bently Nevada machinery monitoringsystems that are compatible with the Velomitor .®

Section 2 gives instructions for receiving and inspecting the Velomitor , choosing the proper®

monitoring points, and mounting the device. This section also shows how to install connectingcables.

Section 3 tells how to maintain the Velomitor by describing the test procedures and®

equipment needed to verify that the device is operating properly.

Section 4 contains instructions for field testing and troubleshooting problems with theVelomitor and compatible Bently Nevada monitoring systems.®

The Appendix provides detailed specifications and sensitivity curves representing typicalVelomitor operation. It also provides instructions for installing Velomitor to meet CE®

requirements.

RELATED DOCUMENTS

3300/55 Dual Velocity Monitor Maintenance Manual, 83965-01


iv

ContentsSection 1 — Operating Information

Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2Ordering Options and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Velomitor Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4®

Mounting Adapters — Option AA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4Agency Approvals — Option BB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Compatible Monitoring Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Cable Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6Transducer Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Section 2 — InstallationReceiving Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1Installing the Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Positioning the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Installing Interconnect Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2Routing Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2Routing Conduit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Routing Armored Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Sealing the Interconnect Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Power and Signal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Section 3 — MaintenanceTest Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Performance Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3Polarity Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Section 4 — Field Testing and Troubleshooting

AppendixSpecifications

Velomitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 1®

Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 1Environmental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 2Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 2Mechanical Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 3Velomitor Frequency Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 4®

Velomitor Phase Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 5®

Interconnect Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A - 6CE installation notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A -7

Velomitor Operation Manual Section 1 — Operating Information®

1

Section 1 — Operating Information

Application

Velocity sensors measure machinery casing vibration and areused on machines where using eddy current proximitytransducers is not practical. Typical applications includepumps, electric motors, compressors, and fans.

CAUTION

Casing measurements may not be appropriate forsome machinery protection applications.

If you measure the velocity of casing vibration to protectmachinery, evaluate the usefulness of the measurement foreach application. Most common machine malfunctions, suchas unbalance or misalignment, occur on the rotor and originateas an increase (or at least a change) in rotor vibration. In orderfor any casing measurement alone to be effective for overallmachine protection, a significant amount of rotor vibration mustbe faithfully transmitted to the machine casing or mountinglocation of the sensor.

Care should be exercised in the physical installation of thesensor on the bearing housing or machine casing. Section 2tells how to install the sensor.

CAUTION

Improper installation may result in a decrease in thevelocity sensor's amplitude and frequency responseand/or the generation of false signals which do notrepresent actual vibration.

Section 1 — Operating Information Velomitor Operation Manual®

2

Principle of Operation

The Velomitor is a piezoelectric velocity sensor. The sensing®

element of the device is a piezoelectric ceramic compressed,by means of a screw, between a metal base and a seismicmass. When subjected to machinery vibration, thismass/spring system exerts a force on the piezoelectric ceramicwhich generates a signal proportional to that force. This signalis amplified and integrated within the sensor to produce a low-noise output signal proportional to velocity.

CAUTION

A piezoelectric velocity sensor subjected to a suddenmechanical impulse may generate a low frequencysignal that does not represent actual machineryvibration. This signal may change the state of alarmand/or danger relays.

The Velomitor is designed to monitor vibration in frequencies®

ranging from 4.5 Hz to 5 kHz. It has a calibrated sensitivity of100 mV/in/s (4 mV/mm/s) and can measure velocities up to 50in/sec pk (1270 mm/s pk). Its stainless steel casing protects itin highly corrosive environments. The operating temperaturerange is from -67 to 250 F (-55 to 121 C). B B B B

The Velomitor is more durable and accurate then traditional®

seismic transducers. The sensing element of the traditionaldevice is composed of a moving wire coil surrounding a fixedmagnet. Because the Velomitor contains no moving parts, it is®

more durable and less sensitive to transverse motion thantraditional seismic transducers. Its piezoelectric sensingelement and solid state circuitry let the Velomitor withstand®

years of continuous use.

The Velomitor is a two wire device which requires an external®

power supply. The power supply must provide a DC voltage of22 to 30 Volts and a current of 10 mA. A constant currentdiode must be used to limit the current to the sensor to 2.5 to 6mA. A simple block diagram of the Velomitor system appears®

in Figure 1-1.


3

Figure 1-1 Velomitor Block Diagram®

The Velomitor internal circuitry automatically sets the DC®

output bias when a constant current is supplied. The DC biasand AC signal appears between pins "A" and "B".

CAUTION

A constant current diode or other current regulating circuitry must be used to provide power to theVelomitor . Failure to do so may reslut in damage to®

the device and/or improper operation.

Compatible Bently Nevada monitoring systems provide thepower required by the Velomitor without the need for®

additional external circuitry.


4

Ordering Options and Accessories

Velomitor Options®

When ordering a Velomitor you may choose from the following®

list of options.

Table 1-1Ordering Information

Part Number: 330500 - AA - BB

Part Number Options

330500 AA BB Description

01 1/2 - 20 UNF P/N 89409-01

02 M8 X 1 P/N 89410-01

03 1/4 - 28 UNF P/N 89411-01

04 1/4 - 20 UNC P/N 89412-01

05 1/4 - 18 NPT P/N 89413-01

00 None Required

01 Pending Canadian Approval

02 Pending British Approval

03 Pending American Approval

Mounting Adapters — Option AA

The base of the Velomitor is machined with a 3/8-24 internal®

thread that will accommodate a variety of purchased orcustomer-manufactured mounting studs. Bently Nevada offersthe 5 adapter studs listed in Table 1-1. You can order one studwith each transducer or purchase the studs separately. TheBently Nevada part numbers used for ordering separateadapter studs also appear in Table 1-1.


5

Figure 1-2 Dual Velocity Monitor System 3300/55

Agency Approvals — Option BB

Agency approvals are currently pending. Consult with your localBently Nevada sales representative for information regardingapprovals status.

Compatible Monitoring Systems

The Velomitor is compatible with the Bently Nevada 3300/55®

Dual Velocity Monitor. This system continuously monitorsmachinery vibration on two channels and can accept inputsfrom one or two velocity sensors. The 3300/55 Monitor with theVelomitor option may be used in any 3300 System Rack that®

provides a -24 volt DC transducer output voltage.


6

The flexibility of the 3300/55 Dual Velocity Monitor makes itideally suited for use with piezoelectric velocity sensors. Youcan adjust the Alert and Danger setpoints and filtering toisolate, eliminate, or emphasize specific vibration frequencies.The monitor can also be configured to integrate both channelsin order to provide output in terms of displacement. OK circuitrycontinuously monitors field wiring and detects open circuits andsensor malfunctions.

The monitor is ready for computer interfacing. No additionalhardware is required to enhance the system for computerizeddata access using Bently Nevada standard on-linecomputerized monitoring hardware and software.

Cable Options

The Velomitor requires a two-conductor cable. We®

recommend using shielded cable to minimize noiseinterference. Table 1-2 describes the Bently Nevada cablesused with the Velomitor . Figures 1-3 and 1-4 show the®

configuration of the cable and connector. You may use eitherBently Nevada cable or other comparable cable. If you useanother cable, be sure it is compatible with the environment.

TABLE 1-2INTERCONNECT CABLE AND ACCESSORIES

APPLICATION P/N CABLE DESCRIPTION

Standard TemperatureUnarmored Cable

9571 - AA Shielded 22 AWG (0.325 mm ) cable with2

moisture resistant female socket connector attransducer end, ring lugs at monitor end.Temperature range -20 to 250° F (-29 to 121° C).

Standard TemperatureArmored Cable

84661 - AA Same as the 9571 - AA but with flexible stainlesssteel armored cable.

Bulk Cable 02173006 Two-conductor shielded bulk cable. 18 AWG.Specify number of feet.

Spare Connector 00531061 Velomitor Connector®

Spare Connector Clamp 00530574 Connector Clamp


7

Figure 1-3 Standard Temperature Unarmored Interconnect Cable

TABLE 1-2 INTERCONNECT CABLE AND ACCESSORIES

APPLICATION P/N CABLE DESCRIPTION

Cable for use withweather proof housing

89477-AA Two-conductor shielded cable with a connectoradapted for use with the 21128 VelocityTransducer Housing Assembly.

AA - Specifies the length of cable required


8

Figure 1-4 Standard Temperature Armored Interconnect Cable


9

Transducer Accessories

ACCESSORY BENTLY NEVADA PART NO.

Velocity TransducerHousing Assembly

Requires a1/2 - 20 UNFVelomitor®

adapter stud.

21128

Quick ConnectSemi-permanentmounting methodusing permanentlymounted bolts.Several bolts can bemounted and a singlevelocity transducercarried from bolt tobolt to measurevibration.


adapter stud.

46122-01

Super Mag 100Quick temporarymethod for mounting avelocity transducer.


adapter stud.

46000-01

Junction Boxes

Weather proof or explosion proofhousing for making electricalconnections to interconnect cables.

03818016 (Body and Cover)03818022 (Cavity extension)03818065 (1/2 inch Conduit) (1.27 cm)03818066 (3/4 inch Conduit) (1.91 cm)

Flexible Conduit 1/2 in. (1.27 cm) 3/4 in. (1.91 cm)

A convenient way to protect cablesfrom moisture and abrasion.

14847 - AA14848 - AA

AA - Specifies required length

(See Bently Nevada Catalog or your Local Bently Nevada Sales Representative fordetails.)


10

Velomitor Operation Manual Section 2 — Installation®

12-1

Section 2 — Installation

Receiving Inspection

Inspect the components of the order as soon as you receivethem to see if there was any damage during shipping. Keep allshipping forms and invoices. If any shipping damage isapparent, file a claim with the carrier and submit a copy toBently Nevada Corporation. Include all model numbers andserial numbers with the claim. We will either repair or replacedamaged parts according to the terms and conditions of thesale.

The velocity sensor is shipped in a foam filled package and theconnector will be protected with a red screw-on plastic cap.The Velomitor is a sensitive instrument and these precautions®

help to prevent damage during shipping.

Installing the Transducer

Positioning the SensorFor optimum performance and accurate measurements the velocitysensor should be placed at a position on the machine casing that is most responsive to vibration.Proper placement is often dependent on the application. Bently Nevada offers MachineryDiagnostic Services which can help determine the best place to mount the sensor for yourapplication.

MountingFollow these steps to install the Velomitor :®

Step 1— Check that the ambient temperature and the temperature of the installation surface iswithin the temperature rating of the transducer.

Step 2— Decide if you need a protective housing for the sensor. We recommend using theVelocity Transducer Housing Assembly (P/N 21128) if the Velomitor or its connecting cable will®

be exposed to possible physical damage during maintenance operations or by operating in anenvironment containing solvents, corrosives, or excessive moisture.

Step 3— Check that the mounting site is flat, clean, and dry. The sensor requires a flat surface

Section 2 — Installation Velomitor Operation Manual®

2-2

at least 1.25 inches in diameter. For the best results the roughness of the mounting surfaceshould be no more than 32 microinch RMS and its flatness should be at least .0008 inches TIR.

Step 4— Drill and tap the mounting hole to the dimensions required by the adapter stud. Drillthe hole so that the sensitive axis of the transducer will be perpendicular to a tangential plane onthe machine casing. For the best results the perpendicularity of the hole should be no more then± 6 minutes.

Step 5— Apply one drop of Loctite 242 or an equivalent adhesive to both ends of the mountingstud.

Step 6— Apply a small portion of Sperry Multi Purpose Ultrasonic Couplant (P/N 04567900) tothe mounting surface.

Step 7— Using the adapter stud tighten the Velomitor to the mounting surface with maximum®

torque of 40 in-lb (4.5 N.m).

Installing Interconnect Cable

Routing CableBently Nevada Corporation supplies interconnect cables with ring lugs ormilitary-type circular connectors. The cable connector must be compatible with the Velomitor®

connector.

When installing the interconnect cable, route it away from the moving components of themachine and avoid sharp corners. To minimize noise, avoid routing cables in the same cable traywith high voltage power lines. Tie the cable to a stationary part of the machine to prevent it fromwhipping and eventual failure. Prevent the cable from bending sharply, twisting, kinking, knotting,or straining. To prevent physical damage route the cable through conduit. Before pulling cablethrough conduit, protect the connector or terminals by wrapping them with tape or a similarcovering. Be sure that the cable does not rub against rough or sharp surfaces.

CAUTION

Improper routing of cables through conduit can cause frayed wiring which may result in a short or loss ofsignal.

Routing Conduit


32-3

To route cable through conduit, connect one end of the conduit to the protective enclosure orother structure in which the monitor is mounted. Connect the other end of the conduit rigidly to astructure near the Velomitor . If the cable must be routed inside lubrication oil lines, be sure it will®

not be subjected to temperatures exceeding its specified operating range.

Routing Armored CableIf the cable is not routed inside conduit, use armored cable and secure it to supporting surfaceswith clips or similar devices. Route the cable through protected areas to reduce the chance ofdamage. Connect one end of the armor directly to the enclosure or other structure in which themonitor is mounted. Connect the other end of the armor rigidly to a structure near the Velomitor .®

The recommended minimum bend radius for armored cable is 1.5 inches (38.1 mm).

Sealing the Interconnect CableWhen conduit-enclosed cable is routed through oil or gaseous environments, seal the ends ofthe conduit to prevent leakage into the protected enclosure. Table 2-1 describes the strategiesthat should be used to seal conduit and the differential pressures at which they apply.

Table 2-1Conduit Sealing Techniques

Differential Pressure Seal Type

less than one atmosphere ZY5 cable seal similar to Bently NevadaP/N 10076-10 for unarmored cable andP/N 10076-03 for unarmored cables or ductseal putty

greater than one atmosphere special interconnecting cable. (ContactBently Nevada for details.)

Bently Nevada cable seals protect against splash and abrasionbut they do not protect against immersion. Contact BentlyNevada if greater protection is required.

Power and Signal Connections

Connections are made to the "A" and "B" terminals of theVelomitor through the terminal connector of the interconnect®

cable. At the monitor end of the cable, connect the cable "A"lead to the "A" terminal on the monitor and the "B" lead to the"B" terminal. The terminal connections for the 3300/55 Dual

Section 2 — Installation Velomitor Operation Manual®

2-4

Figure 2-2 3300 / 55 Field Wiring Diagram

Velocity Monitor appear in Figure 2-2. Refer to the 3300/55Dual Velocity Monitor Maintenance Manual (P/N 83965-01) forfurther information.


52-5

Velomitor Operation Manual Section 3 — Maintenance®

13-1

Section 3 — Maintenance

This section shows how to check the performance of theVelomitor . Table 3-1 lists the recommended maintenance®

equipment . If the equipment is not available, contact thenearest Bently Nevada Corporation field office, or return thetransducer to the factory or a testing laboratory for testing.

Table 3-1Recommended Maintenance Equipment

Recommended Equipment Specification

MB DynamicsModel PM50 Exciter Shake Table

MB Dynamics, Model 2250 Power Amplifier

Krohn-Hite Model 1200A Function Generator(Bently Nevada Corp. P/N 02280852)

Tektronix 2235 Oscilloscope, Bently NevadaCorp. P/N 02280741

Bently Nevada Corporation Model 330100-50-00 Proximitor®

Model 330101-00-08-10-02-00 Probe Model 330130-040-00-00 Extension Cable

Power Supply, Bently Nevada TK15 -24.0 Vdc with minimum output current of 20mA and less than 5 mV peak-peak noise

AISI 4140 Steel Target Material 0.030 inch (0.762 mm) thick, 0.85 inch (21.6mm) diameter, 16 µin pp (0.41 µm pp)

3 mA (Motorola P/N 1N5309) current diodeBently Nevada Corp. P/N 00643485

Section 3 — Maintenance Velomitor Operation Manual®

3-2

Figure 3-1 Velocity Transducer Test Equipment Setup

Figure 4-1 Probe and TargetPosition

Test Setup

Step 1— Connect testequipment as shown in Figure 3-1.

Step 2— Mount the 4140 steeltarget to the shake table so that itis rigidly attached to the movingarmature as shown in Figure 3-2.

Step 3— Mount a 3300 8mm, 1meter probe (P/N 330101) suchthat it is isolated from the motionof the shake table.

Step 4— Connect the probe toa four meter extension cable (P/N330130-040-00-00) andProximitor (P/N 330100-50-00). ®

Step 5— Apply -24 Vdc powerto the Proximitor and monitor the output with®

a voltmeter or oscilloscope.

Note

The accuracy of the system can be improvedby mountingthe probe and target on the sameaxis as the sensitive axis of the Velomitor®

and by verifying that there are no mechanicalresonances in the probe or target fixture atthe frequency of calibration (100 Hz).

Step 6— Mount the velocity sensor to bechecked on the shake table and tighten byhand.

Step7— Adjust the probe-to-target gap so that the Proximitor output is at midrange,-10.0 ± 0.5 Vdc.®

Step 8— Connect the velocity transducer to the

DISPLAY GOES POSITIVE

Velomitor Operation Manual Section 3 — Maintenance®

33-3

Figure 5-1 Polarity CheckOscilloscope Display

oscilloscope or voltmeter as shown in Figure 3-1.

Performance Test Procedure

Step 1— Set the signal generator to 100 ± 1 Hz and adjustthe power amplifier gain so that the Proximitor output is .318± .003 volts peak-to-peak (0.112 ± 0.001 volt RMS). Thissignal corresponds to a peak-to-peak displacement of0.00159 inches (0.0404 mm) and a peak-to-peak velocity of1.0 inch per second (25.4 mm/s).

Step 2— Verify that the output of the velocity sensor isbetween .095 and .105 volts peak-to-peak (.0336 to .0371volts RMS). If the output is not in this range, return the unitto the factory.

Polarity Test ProcedureUse this test to verify the proper phase response. Any out ofphase response will adversely affect machinery balancing.

Step 1— Connect the cable asshown in the setup in Figure 3-1.

Step 2— Set the time base onthe oscilloscope to 20milliseconds/division.

Step 3— Hold the velocitysensor in hand and tap thebottom. Observe that the wave-form on the oscilloscope firstgoespositive as shown in Figure 3-3. Ifit goes negative first, return theunit to the factory forreplacement.

Velomitor Operation Manual Section 4 — Field Testing and Troubleshooting®

14-1

Section 4 — Field Testing and Troubleshooting

Use the following procedure to test an installed Velomitor and®

isolate a suspected malfunction. The Velomitor is a®

hermetically sealed unit with no adjustments or field repairablecomponents. If you determine that the Velomitor is not®

functioning properly, return it to a factory authorized repaircenter for further evaluation and disposition.

When the Velomitor is used with a Bently Nevada monitoring®

system, a sensor fault is indicated when the monitor's OK LEDgoes OFF. A fault may be due to a sensor malfunction or amalfunction in the field wiring. Before troubleshooting asuspected problem, check that the sensor has been correctlyinstalled and that all connections are secured and in the properlocations. If the sensor is properly installed, use Table 4-1 tohelp identify the problem.

Table 4-1 Troubleshooting Guide

Possible Fault Corrective Action

Monitor Power is OFF. Check that the Monitorpower supply is pluggedin and power is ON.

Interconnect cable isdisconnected, connectedloosely, or connected to thewrong monitor.

Verify that the transduceris connected to thecorrect monitor and to thecorrect monitor terminals.Check that the screws aretight.

Section 4 — Field Testing and Troubleshooting Velomitor Operation Manual®

4-2

Table 4-1 Troubleshooting Guide (Continued)

Possible Fault Corrective Action

Interconnect cable is not connectedor connection is loose at thetransducer

Verify that the transducer isconnected either visually or bymeasuring the resistance at themonitor end of the interconnectcable. If the resistance is not 400to 600 kS, the cable ortransducer may be damaged.

Transducer Open or short Disconnect the interconnectcable from the transducer andmeasure the resistance acrosstransducer terminals "A" and"B". If it is less than 400 kS orgreater than 600 kS, replace thetransducer.

Interconnect Cable is Damaged -Short

Visually inspect the cable forapparent damage. Disconnectthe cable and measure theresistance between the twoconductors, "A" to "B". Ifintermittent or shorted, replacethe cable.

Interconnect Cable is Damaged -Open

Disconnect the cable andmeasure the resistance of eachconductor from end to end. Ifopen circuited, replace the cable.

Transducer is not isolated. Measure the resistance betweenthe "A" and "B" terminals of thetransducer and the mountingstud. If the resistance is not 1MS or greater for both terminalsreplace the transducer.

Velomitor Operation Manual Appendix A — Specifications®

1A - 1

AppendixSpecifications

Velomitor®

Parameters are specified at 77° F (25° C) unless otherwise indicated

ElectricalSensitivity 100 mV/in/s (4 mV/mm/s) ± 5% at 100 Hz

Frequency Response ±0.9 dB 6.0 Hz to 2.5 kHz ±3.0 dB 4.5 Hz to 5.0 kHz

Velocity Range 50 in/s pk

Transverse Sensitivity less than 5% of axial

Amplitude linearity ± 2% to 6.0 in/s pk

Mounted Resonant Frequency 12 kHz minimum

Power Requirement DC Voltage 22 to 30 Vdc Bias Current 2.5 to 6 mA

Output Bias Voltage 12.0 Vdc (nominal)

Dynamic Output Impedance less than 1500 S

Broadband Noise Floor 160 µin/s

Grounding Case isolated

Maximum Cable Length 1000 ft (305 m) with no degradation ofsignal

Appendix A — Specifications Velomitor Operation Manual®

A - 2

EnvironmentalOperating Temperature Range -67 F to 250 F (-55 to 121 C)B B B B

Shock Limit 2500 G pk minimum

Humidity Limit 100% Relative

MechanicalWeight 5.3 ounces (150 grams) Typical

Diameter 1 inch (25 mm)

Height 2.6 inch (66 mm)

Case Material 316L Stainless Steel

Connector 2 pin Mil-C-5015 hermetically sealed,304 stainless steel shell

Mounting Torque 40 in-lbs (4.5 N m)

Polarity Pin A goes positive with respect to pin Bwhen the transducer case motion is towardthe connector.

Mechanical Drawing


3A - 3

Figure A-1 Velomitor Mechanical Drawing®


A - 4

Velomitor Frequency Response®


5A - 5

Velomitor Phase Response®


A - 6

Interconnect Cable

Size 22 AWG (0.325 mm )2

MaterialsConductor Silver Plated Copper

Insulation TFE 0.010 inch (0.254 mm) Nominal Wall

Shield Braided Silver Plated Copper

Jacket Extruded FEP - White

Voltage Rating 600 V

Bend Radius-Unarmored 1.00 inch (2.54 cm)Bend Radius-Armored 1.50 inch (3.81 cm)

Tensile StrengthCable 10 pounds (44.5 N)

Connector to Cable 10 pounds (44.5 N)

Terminal to Cable 10 pounds (44.5 N)

Operating Temperature Range -20 to 250 F (-29 to 121 C)B B B B

Nominal O.D. 0.143 inch (3.63 mm)

Stranding 19/34

Capacitance 45 pF/ft (150 pF/m) grounded 25 pF/ft (82 pF/m) mutual


7A - 7

CE INSTALLATION NOTES

The Velomitor was tested at a recognized facility and found to be compliant with europeanelectromagnetic compatibility directive 89/336/EEC (EMC Directive). The applicable norms are:EN55022, EN50081-2, prEN50082-2, ENV50140.

Testing and Test Levels

Test Specification Requirement

Electrostatic Discharge IEC 801-2 (1991) 8KV contactEN50082-2 (1993) 8KV air

Radiated Susceptibility IEC 801-3 (1984) 27 - 1000 MHzEN50082-2 (1993) 10 V / m

Radiated Susceptibility ENV50140 (1993) 900 MHzEN50082-2 (1993) 10 V / m

Conducted Susceptibility ENV50141 (1993) 150 Khz - 80 MHz12 V criteria A

Electrical Fast Transient IEC 801-4 (1988) 2 KVENG1000-4-4 Level 4 Criteria B


A - 8

CE Installation Instruction These instructions are in addition to those containedelsewhere in this manual.

Sensor - The Piezo-Velocity Sensor should bemounted to a machine in such a manner that itmakes good electrical contact with the machinewhich itself should be thoroughly grounded.

Cable - The cable shield on the monitoring side,should be grounded to the shield of the receivingsystem (metal enclosure of monitoring system orjunction box if applicable). This will provide a pathto ground for electromagnetic interference (EMI)energy.

vibration manual

Documents

Transcript of vibration manual