IRD Mechanalysis IRD811 Manual

Customer Details
Date Purchased:
IRD Serial Number (s):
P.O. ref:
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End User:
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IRD Mechanalysis Limited
IRD811
Vibration Spike Energy Detector
Operation & Maintenance Manual
Version 2.0
May 2013
IRD Mechanalysis Limited
1/5,MarolCo-opInd. Estate Ltd
Off. M. Vasanji Road, Marol
Andhedri (E), Mumbai – 400 059
Tel: [phone], Fax: [phone]
Email : [email protected]
Web: www.irdmechanalysis.com

IRD811 O&M Manual IRD Mechanalysis
®
Limited
I
condition management solutions
IRD Mechanalysis Limited
www.irdmechanalysis.com
IRD Mechanalysis Limited continues to be the industry leading provider of Condition
Management Solutions. With over 30 years’ experience in machinery vibration and
associated condition monitoring technologies, the company designs and manufactures
proven instrumentation suitable for rugged industrial environments. A comprehensive range
of products and services are available from the offices below.
Location Addresses Contact Numbers
Delhi
Sagar Deep, Plot No.11, LSC Saini Tel:[phone]
Enclave, Vikas Marg, Fax:[phone]
New Delhi 11009
2
Email:
-
[email protected]
Kolkata
153/A, 2nd Floor, VIP Road,
Kolkata 700 054
Tel:[phone]
Fax:[phone]
Email:[email protected]
Mumbai
1/5 Marol Co-op. Industrial Estate
Ltd, Off. Mathurdas Vasanji Road,
Marol, Andheri (East),
Mumbai 400 059
Tel:[phone]
Fax:[phone]
Email:[email protected]
Chennai 7-C Chesney Nilgiri Apartments Tel:[phone]
65,Commander-In-ChiefRoad Fax:[phone]
Chennai 600 105 Email:[email protected]
National
Service Centre
& Works
1/5 Marol Co-op. Industrial Estate
Ltd., Off. Mathurdas Vasanji
Road, Marol, Andheri (East),
Mumbai400059
Tel:[phone]
Tel:+91
-
02
2
-
28596214/6573
Fax:[phone]
Email:[email protected]

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INDEX OF ILLUSTRATIONS
INDEX OF REFERENCE FIGURES
Figure Title Page
1. Periodic Vibration Measurement Save Valuable machine
downtime 1
2. Standard Package of IRD811 2
3. IRD 811 Standard Accessories 3
4. IRD 811 Optional Accessories 4
5. Front view of IRD811 showing all the controls, indicators &
connectors
6
6. A typical vibration measurement datasheet 14
7. A general machinery vibration severity chart (Metric) 16
8. A general Machinery Acceleration Severity Chart 17
9. Dominant Vibration Frequency Chart 18
10. Sample Balancing Vector Diagram 21
11. Battery Replacement Details 23
12. Calibration Test Connections 25
13. Rolling Element Bearing gSE Severity Chart 33
INDEX OF REFERENCE TABLES
Table Title Page
1. Amplitude ranges for IRD811 7
2. Measure units, ranges and meter scale used in IRD811 8
3. Amplitude ranges for IRD811 Vibration Spike Energy Detector 9
4. Tentative guide to vibration tolerances for machine tools 15
5. Dominant machine excitation frequencies and most likely
causes
19

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TABLE OF CONTENTS
Sr.No. Chapter Description Page No.
1 INTRODUCTION 1
Getting you started
2 DESCRIPTION 2
2.1 General
2.2 Description of controls indicators and connectors
2.3 Description of Accessories
3 PREPARATION FOR OPERATION 9
3.1 General
3.2 Checking Instrument Operation
3.3 Accelerometer Mounting
3.4 Model IRD544 Inductive Velocity Sensor Mounting
4 OPERATION 13
4.1 General
4.2 Setup
4.3 Vibration Measurement
4.4 Determining Vibration Severity
4.5 Determining dominant Vibration Frequency
4.6 In-Situ Balancing
5 SERVICE 23
5.1 Field Maintenance
5.2 Spare Parts Listing
5.3 Instrument Calibration Procedures
6 SPECIFICATIONS 29
6.1 IRD811 Portable Vibration Meter (Accelerometer)
6.2 IRD511 Accelerometer
7 APPENDIX- A 32
Keeping you going
8 SUPPORT SERVICES 34
Taking you further
9 VIBRATION BASED CONDITION MONITORING SOLUTIONS 38

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1. INTRODUCTION
This instruction manual describes the IRD Mechanalysis model IRD811 Vibration-SPIKE
ENERGYTM Detector. Included in this manual are complete instructions on the preparation,
setup, operation, and service of these instruments. Specifications of the model IRD811 and
the major accessories are provided in Appendix A. Information on the significance of the
measured vibration amplitude levels in displacement, velocity & acceleration and the
procedures for evaluating SPIKE ENERGY
measurements are well covered in the
manual.
The Vibration-SPIKE ENERGY (gSE) Detector is a compact, portable instrument which can
be hand-held for taking vibration measurements or for balancing rotating machinery. This
instrument measures machinery vibration in units of displacement, velocity, or acceleration.
In addition, it also measures the SPIKE ENERGY signals associated with bearing and gear
defects over a very wide range of frequency
The operating conditions which may eventually cause the breakdown of a rotating machine
can be detected from the measurements provided by the Vibration-SPIKE ENERGY
Detector. Periodic measurements of machine vibration, combined with a time log of the
vibration levels, provide the basic information needed for an effective Predictive Maintenance
Program for rotating machinery (Figure 1). If significant increases develop in the machine
vibration levels, then trouble is indicated in the machine. These troubles can then be
pinpointed to specific parts of the machine, and scheduling can be more conveniently
arranged for effecting repairs.
Figure 1 Periodic Vibration measurements save valuable machine downtime
IRD Mechanalysis offers complete training on vibration measurement, analysis, and
balancing
in principal cities throughout the world. For details on the training programs and
other
services that are available, contact your nearest IRD Mechanalysis representative,
or write to
IRD Mechanalysis, Limited.

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Getting you started
2. DESCRIPTION
2.1 GENERAL
Thank you for investing in IRD Mechanalysis Vibration Meters. We trust that like many
thousands of users before you will continue to enjoy optimum value from your wise
investment. IRD Mechanalysis Limited is an independent System Integration Company
that designs and manufactures condition monitoring system solutions.
This chapter contains descriptions of the model IRD811 Vibration-SPIKE ENERGY Detector
and the standard and optional accessories available for use with this instrument.
Figure 2 Standard package for IRD 811 Vibration-SPIKE ENERGY Detector
The standard package for the instrument shown in Figure 2 contains the following
accessories:
Standard Accessories Qty Part Number
Accelerometer Multi-purpose, model IRD511 - 100 mV/g, 2.0
Hz - 10 kHz, top connector
Cable Assembly for model IRD811 to IRD511 Accelerometer
sensor - 1.5m rubber insulated, shielded
1 M5111005001000
2 M60021
Stinger Al 225mm Straight for Sensor 1 M24827
Carrying Case 1 M25345
Battery Set, 3 Nos. of 9V, 100mAH Dry Cells 1 M30643
Manual Operating 1 M21072
Magnetic Portable Base fo
r
IRD
A
ccelerometers 1 M24828

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OptionalAccessories Part Number
Inductive Velocity Senso
r
model IRD544 M45260
Cable fo
r
Model IRD544 Senso
r
1.5m M20432
Cable fo
r
Model IRD544 Senso
r
8m M21045
Ma
g
netic Portable Base fo
r
IRD544 Inductive Velocit
y
Sensors M24823
Magnetic Deflecting Shroud fo
r
model IRD544 Senso
r
M60018
Shaft Fish Tail Stick -
A
bsolute Vibration IRD500 Series M24824
Manual Training - IRD Mechanalysis Vibration Technology 1 M51001
2.2 DESCRIPTION OF ACCESSORIES
2.2.1 STANDARD ACCESSORIES
The standard accessories available for use with the model IRD811 are illustrated in figure 3
and are described below
Figure 3 IRD 811 Standard Accessories
A) IRD511 Accelerometer
The IRD511 Accelerometer can be used in any position without loss of accuracy or
sensitivity. It is sensitive to vibrations along the long axis, and can be fastened to rotating
machinery with a M6 stud. It can also be used with a magnetic Portable Base, or hand-held
with or
without the 9-inch extension probe installed.
B) Cable for accelerometer 1.5 m – 2 nos.
The sensor cable connects the accelerometer vibration signal to the 6 pin threaded
Receptacle at the top end of the instrument. In addition, this cable also carries the DC supply
voltage to the internal amplifier of the Accelerometer. The cable connector at the external
A
B
B
C
D
E

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end of the cable connects to the 2-pin receptacle on the end of the accelerometer.
C) Stringer
The Stringer, Part No. M24827 is 225 mm in length and connects to the threaded hole at the
flat end of the accelerometer. It is used to reach inaccessible places on the
rotating
machine when the accelerometer is hand held. The probe should not be used to
measure vibration signals above 16,000 CPM, except in the Bearing-Gear (gSE) mode of
operation.
D) Battery Set, 3 Nos. of 9V, 100mAH Dry Cells
E) Magnetic Portable Base for Accelerometer
The Magnetic Portable Base is used, when required, to hold the accelerometer to the rotating
machine. The magnetic holder is stud mounted to the flat end of the Accelerometer and
provides a strong magnetic force for securing the sensor to the rotating machine. This holder
can be used for vibration measurement of frequency components up to 60,000 CPM. For best
results, it is recommended that silicon grease be applied to the contact surfaces
F) Carrying Case (Not shown)
The Carrying Case provides space for carry or storing the instrument along with the standard
accessories.
G) Manual Operating (Not shown)
The Operating Manual provides instructions on setup, operation, and service of the model
IRD811 Vibration-SPIKE ENERGY Detector. Additional copies of the manual could be
obtained fromIRD Mechanalysis.
2.2.2 OPTIONAL ACCESSORIES
The optional accessories available for use with the model IRD811 are illustrated in figure 4
and are described below.
Figure 4 IRD 811 Optional Accessories
A) IRD544 Inductive Velocity Sensor
The IRD544 Inductive Velocity Sensor is used in place of the accelerometer, when preferred,
For vibration measurement in displacement or velocity. The IRD544 can be mounted in any
position without affecting the accuracy or sensitivity (within the specification limits listed for
this sensor). This sensor is sensitive to vibration along its long axis and can be stud mounted
A
B
C
D
E

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to the rotating machine, used with a magnetic holder, or hand-held to the machine with or
without the extension probe.
B) Cable for IRD544 Sensor 1.5m
The IRD544 Sensor Cable is 1.5 meters in length and connects the sensor vibration
signal to
the instrument. The 6 pin threaded connector is connected to the corresponding
receptacle
at the top end of the instrument. The threaded receptacle at the opposite end
of the cable
connects to the connector on the end of the IRD544 Sensor. This cable may
also be used
to connect the Model IRD811 to a vibration analyzer.
C) Cable for IRD544 Sensor 8m
The Extension Cable is 8 meters in length and when required, is connected to the external
end
of the standard cable to increase the overall IRD544 cable length to 29 feet.
D) Magnetic Portable Base for IRD544 Inductive Velocity Sensors
The Magnetic Portable Base is used to hold the model IRD544 Sensor to the rotating
machine when
required. The magnetic Portable Base stud mounts to the flat end of the
sensor and provides a
strong magnetic force for holding the sensor to the machine. This
holder can be used when
measuring vibration containing frequency components up to
60,000 CPM. For best results, it
is recommended that silicon grease be applied to the mating
surfaces.
E) Magnetic Deflecting Shroud for model IRD544 Sensor
The Magnetic deflecting shroud is used with the model IRD544 Velocity Sensor, when
required, to
reduce the magnetic field effects to 0.0015 inch/second gauss (l00:I reduction)
at 60 Hz.
The magnetic Deflecting Shroud fits over the IRD544 Sensor.
F) Vise Grip Plier (Not Shown)
The Vise Grip Plier is used as an item of convenience, if desired, for holding the model
IRD544 Velocity Sensor to the rotating machine for balancing. The threaded sensor stud
mounts to the pliers and the plier jaws are to be clamped to the rotating machine.
G) Manual Training - IRD Mechanalysis Vibration Technology 1 (MVT1) (Not
shown)
This is a comprehensive vibration training course manual for beginners, practicing vibration
engineers and plant managers to learn and practice the science of vibration diagnostics and
root cause analysis for improved machine uptime and reliability.

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2.3 DESCRIPTION OF CONTROLS, INDICATOR AND CONNECTORS
This section contains descriptions of the instrument controls, amplitude meter, and
connectors. The front view of the model IRD811 is shown on Figure 5.
Figure 5 Front view of IRD811 showing all the controls, indicators & connectors
A) Amplitude range selector
The amplitude range selector is used to select the full-scale amplitude range to be read on
the Amplitude meter. In Metric units, the ranges extend from 1 to 3000 micrometers pk-pk,
or mm/sec pk., In addition, the model IRD811 is also equipped with ISO ranges from 1 to
3000
mm/sec, RMS. The eight amplitude ranges that may be selected on each instrument
model
are listed in Table 1.
C
D
A
F B
E

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Table 1 Amplitude ranges for IRD811
METRIC UNITS ISO UNITS
microns pk –pk / mm/sec pk g’s pk mm/sec RMS
0 – 1.0 0 – 0.03 0 – 1.0
0 – 3.0 0 – 0.01 0 – 3.0
0 – 10 0 – 0.3 0 – 10
0 – 30 0 – 1.0 0 – 30
0 – 100 0 – 3.0 0 – 100
0 – 300 0 – 10.0 0 – 300
0 – 1000 0 – 30.0 0 – 1000
0 – 3000 0 – 100 0 – 3000
B) Mode Selector
The MODE selector is used to select the desired units of measure which are described as
follows:
i) DISP 350 CPM: provides measurement in DISPLACEMENT (micrometers pk-pk)
from 350 to 120,000 CPM, or 5.8 to 2000 Hz with the accelerometer or- from 600
to 60,000 CPM or 10 to 1000 Hz with the model IRD544 Velocity Pickup.
ii) DISP 1400 CPM: provides measurement in DISPLACEMENT (micrometers pk-
pk) from 1400 to 600,000 CPM or 23.3 to 10,000 Hz with the accelerometer; or
from 1400 to 60,000 CPM or 23.3 to 1000Hz with the model IRD544 Velocity
Pickup. This mode reduces the low frequency energy in the output, and allows for
a faster response time.
iii) VEL: provides measurement in VELOCITY (mm/sec pk) from 350 to 600,000
CPM or 5.8 to 10,000 Hz with the accelerometer; or from 600 to 60,000 CPM or
10 to 1000 Hz with the model IRD544 Velocity Sensor.
iv) D. ACCEL: provides measurement in ACCELERATION (g's peak) from 120 to
600,000 CPM or 2 to 10,000 Hz), and is used only with the accelerometer.
v) BEARING/GEAR gSE: provides measurement of SPIKE ENERGY units of
Acceleration (g's SE) of bearings, gears, or other machine ports. This mode is
used only with the accelerometer.
vi) ISO: provides International Standards Organization measurement in VELOCITY
(mm/sec rms, from 600 to 600,000 CPM or 10 to 10,000 Hz). This mode is used
only with the accelerometer.
C) Amplitude Meter
The Amplitude Meter indicates the vibration amplitude, and the condition of the internal
batteries in the ‘BATT TEST’ mode of the POWER SWITCH. The upper scale on the meter is
used for Amplitude Range selector settings of 1, 10, 100 or 1000 on the upper scale and the
lower scale for the 3, 30, 300, or 3K settings. The condition of the batteries is shown in the
LO-BATT -HI area of the lower scale in the BATT TEST mode. The meter scales to be used
for the various units and range settings selected are listed in Table 2 below.

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Table 2 Measure units, ranges and meter scale used in IRD811
METRIC UNITS
Micrometer and
mm/sec Ranges Meter Scale Reading g’s Ranges
Meter Scale
Reading
0 – 1 UPPER 0 – 0.03 LOWER
0 – 3 LOWER 0 – 0.1 UPPER
0 – 10 UPPER 0 – 0.3 LOWER
0 – 30 LOWER 0 – 1 UPPER
0 – 100 UPPER 0 – 3 LOWER
0 – 300 LOWER 0 – 10 UPPER
0 – 1000 UPPER 0 – 30 LOWER
0 – 3000 LOWER 0 – 100 UPPER
D) Sensor signal input receptacle
The SENSOR SIGNAL INPUT receptacle is a 6-pin threaded connector. It is located at the
top end of the instrument, and is used for connection of the sensor cable from the
accelerometer (or optional model IRD544 Velocity Sensor).
E) Scope/Tape Recorder/Analyzer output connector
The SCOPE (oscilloscope)/Tape Recorder/Analyzer output connector provides the
output
signal for connecting to oscilloscope, tape recorder, or other vibration analyzer. A
2- pin
threaded connector is required for connection to this receptacle. The full-scale output
signal
voltage is 301 mV, RMS, for Metric units. The load impedance required is 100K ohms.
F) Power Switch
The Power Switch is used to connect the internal battery supply to the instrument circuits,
and to check the batteries for proper output voltage. If set to OFF, the internal power is
disconnected. The switch is set to ON for normal operation. If the switch is set to BATT
TEST, and the batteries have sufficient output voltage, the Amplitude meter will indicate a
reading in the LO-BATT -HI area of the lower scale.
NOTE:
If the meter indicates at or below the LO point of the scale, then the
batteries must be replaced before the instrument can be used. For
extended battery life it is recommended to switch the unit off when not
in use.
.
The Vise Grip Pliers must not be used for vibration measurement except
when balancing a rotating machine. In addition, do not use the Vise Grip
Pliers with the accelerometer.

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3. PREPARATION FOR OPERATION
3.1 GENERAL
This section consists of instructions for setting up and checking the basic operation of the
Vibration-SPIKE ENERGY Detector. Also described in this chapter are the procedures for
mounting the Accelerometer or Velocity Sensor on the rotating machine, connecting the
signal input and output cables, and checking the condition of the internal batteries.
3.2 CHECKING INSTRUMENT OPERATION
The basic operation of the Vibration-SPIKE ENERGY Detector is checked as follows:
1. Set the instrument POWER SWITCH to the BATT TEST position, and check that
the Amplitude Meter indicates within the LO-BATTERY-HI area. If this indication is
obtained, then the internal batteries have sufficient output voltage for operating
the instrument and accelerometer circuits. If the meter indicates at or below the
LO point, the batteries must be replaced before the instrument can be used.
(Replacement details are included in Chapter V.)
2. Connect one end of the sensor cables to the threaded receptacle on the
Accelerometer, and connect the opposite end to the 6 Pin receptacle on the top
end of the instrument.
3. Set the POWER SWITCH to ON. Set the MODE SELECTOR to VELOCITY, and
the AMPLITUDE SELECTOR to the 30 mm/sec pk range. Then, shake the
accelerometer and check that a vibration reading is indicated by the Amplitude
Meter (the meter indicator should move up-scale when the accelerometer is
shaken, and should settle back to zero when the accelerometer is held still)
4. Instrument check with optional Calibrator (P/N M21073) – The optional Calibrator
provides a fast and accurate method for checking the calibration of the Vibration-
SPIKE ENERGY Detector and the integrity of the sensor cable. The procedure for
using the Calibrator is described below:
a) Disconnect the external end of the 4-foot Sensor Cable from the
accelerometer.
b) Connect the sensor end of this cable to the threaded receptacle on the
calibrator. The 6 Pin threaded connector at the opposite end is connected
to the instrument.
c) Set the AMPLITUDE RANGE selector on the IRD811 instrument to the
position listed in the table below for the mode to be tested, then check that
the Amplitude meter indicates a reading within the required limits.
Table 3 Amplitude ranges for IRD811 Vibration Spike Energy Detector
Mode Range
Selector
Mete
r
Scale
Readout
Limits
ISO – mm/sec rms
ACCEL – g pk
VEL – mm/sec pk
DISP (350 or 1400) – um pk-pk
10
1
10
30
0 to 1
0 to 1
0 to 1
0 to 3
6.86 to 7.00
0.85 to .090
9.41 to 10.00
21.4 to 23

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NOTE:
The readout limit values reflect the combined tolerance of the
instrument (+3%) and the calibrator (+1%).
.
If the Amplitude meter indications are within the proper limits, then the instrument
circuits and the sensor cable are functioning correctly. The sensor cable may then be
disconnected from the Calibrator and the POWER switch set to OFF. If the proper
meter indications are not obtained, check for weak internal batteries, defective cable
or instrument, or instrument circuits that are out of calibration.
3.3 ACCELEROMETER MOUNTING
The Accelerometer may be hand-held for most periodic vibration checks, or stud-
mounted for more permanent measurement applications. When required, limited
measurements of vibration can be obtained when the sensor is held to the machine
by use of the magnetic Portable Base, or hand-held with the extension probe
attached. When
measuring SPIKE ENERGY signals, the extension probe is
normally used and the
sensor hand-held. The accelerometer should not be used in
environments where the
temperature exceeds +2500F (+1210C).
When the sensor is stud mounted, it should be located on a flat surface of the rotating
machines at or near the housing of the bearing to be checked, using the ¼-28 x ¼
inch threaded hole at the flat end of the sensor. The long axis of the accelerometer
must be positioned in the direction of the vibration to be measured. The mounting
stud must not extend into the sensor shell by more than ¼-inch, maximum; otherwise,
the sensor could be damaged.
The accelerometer mounting surface must be reasonably flat, smooth, and clean
(free of hardened grease, dirt, scale, paint of other matter). Coating the flat end of the
accelerometer with clean silicone grease will help ensure proper bonding between the
sensor and mounting surface. The accelerometer should be threaded onto the
mounting stud, and hand-tightened to the machine.
DO NOT WRENCH THE ACCELEROMETER TO THE MOUNTING
SURFACE.
The accelerometer can be hand-held to the rotating machine, if desired, for
measurement of vibration displacement, velocity or acceleration up to a frequency of
420,000 CPM. To hand-hold the sensor, the flat end should be held firmly against the
machine housing so that the long axis is positioned in the same direction as the
vibration to be measured. The sensor should be held against a reasonably flat
surface, as any unsteadiness of the hand which allows the direction of the axis to
vary may result in unsteady vibration readings. Sufficient holding force must be used
to keep the sensor from chattering or “walking” on the surface. A tingling sensation in
the holder’s hand is an indication that more force is needed.

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The optional magnetic holder may also be used to secure the accelerometer to the
rotating machine. The magnetic holder is attached to the pickup using the ¼-28x1/4-
inch threaded hole and M6 stud. Silicone grease is normally applied to the mating
surfaces. The maximum vibration frequency to be measured when using the holder
should not exceed 120,000 CPM
For limited vibration measurements, and for the measurement of SPIKE ENERGY
signals, the extension probe can be attached to the sensor and the sensor then hand-
held with the tip of the probe contacting the various measuring points on the rotating
machine. The probe tip should be in firm contact with the bearing housing to prevent
the probe from chattering or ‘walking” on the contact surface. When using the
extension probe, the maximum vibration frequency which can be measured (in
displacement, velocity, or acceleration) is 16,000 CPM. The extension probe enables
the operator to obtain vibration measurements from parts of the rotating machine that
are not readily accessible.
3.4 IRD544 VELOCITY SENSOR MOUNTING
The optional model IRD544 Velocity sensor should be mounted to the rotating
machine in the same manner as described for the Accelerometer. However, the
model IRD544 can be used in temperatures up to +5000F (+2600C).
When possible, the sensor should be stud mounted or hand-held flush against the
machine surface. Vibration measurements may also be obtained using the optional
magnetic Portable Base for this sensor, or by hand-holding the sensor with the
extension
probe attached. If the sensor is hand-held without the extension probe
attached, the
maximum vibration frequency that may be measured is 60,000 CPM. If
the magnetic
holder is used to secure the sensor, vibration frequencies as high as
37,000 CPM
may be measured. If the sensor is hand-held with the extension probe
attached, then
the maximum frequency to be measured is 16,000 CPM.
NOTE:
The IRD544 sensor is not used for SPIKE ENERGY signal
measurement.
.
The Optional magnetic Deflecting Shroud can be used along with the IRD544
Velocity sensor to
reduce magnetic interference that may be present. The Magnetic
Deflecting Shroud fits over the sensor,
and is held by the mounting adapter supplied
with the shroud.
If desired, vise-grip pliers can be used to hold the velocity sensor to the rotating
machine for balancing. The sensor stud mounts to the vise-grip pliers, and the plier
jaws must be securely clamped to the rotating machine. The vise-grip pliers are an
item of convenience for balancing only, and should not be used when measuring the
machine vibration as the maximum measurable frequency is limited to 7200 CPM.
3.5 CABLE CONNECTIONS
SENSOR CABLE: The threaded connector at the external end of the sensor cable
connects to the threaded receptacle at the top end of the accelerometer, or IRD544
Velocity Sensor. This connector should be aligned with the guide key and contact

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pins in the receptacle and then hand-tighten to the receptacle. The treaded connector
at the other end of the cable connects to the corresponding receptacle of the Top end
of the instrument. This connector should be aligned with the receptacle, and then
tightened DO NOT WRENCH EITHER SENSOR CABLE CONNECTOR.
ANALYSER/SCOPE/TAPE RECORDER OUTPUT: The model IRD811, instrument
can be used to provide acceleration measurement capability on any analyser that is
velocity compatible (model 350, etc). To use the vibration SPIKE ENERGY Detector
with an analyser to measure acceleration, connect the threaded end of the 4-foot
IRD544 Velocity sensor to the output receptacle at the bottom of the model IRD811
instrument. The other end of the cable is connected to the twist-lock input receptacle
of the analyser. Set the analyser units switch to VELOCITY, and the AMPLITUDE
RANGE TO ‘1’ (“10” for metric instruments). Then, set the Vibration-SPIKE ENERGY
Detector to the ACCEL mode and adjust the AMPLITUDE RANGE selector to obtain
an on-scale meter reading on this instrument.
The appropriate frequency analysis procedures for the analyser being used may then
be followed The values read on the analyser Amplitude meter are based on the range
setting of the Vibration-SPIKE ENERGY Detector. Although the analyser is set to the
‘1” AMPLITUDE RANGE (“10” for metric instruments), the full-scale value to be read
on the analyser Amplitude meter will be the same as the full-scale reading on the
model IRD811 instrument.
To connect an oscilloscope or tape recorder to the model IRD811, instrument a signal
cable with a velocity sensor connector must be used. The output signal provided by
the IRD811 instrument has a full-scale voltage level of 301 mV, rms, in Metric units.
NOTE:
FILTERED SPIKE ENERGY signal voltages are not provided at
the output connector.

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4. OPERATION
4.1 GENERAL
The Vibration-SPIKE ENERGY Detector is designed to measure the overall machine
vibration amplitude and the SPIKE ENERGY signal levels produced by moving-
element bearing and high speed gears. All vibration readings obtained with the
instrument should be compared to known standards of vibration for the type of
machine, bearing, or gear being checked. If the measured vibration or SPIKE
ENERGY level has significantly increased since the last periodic check, or if the
levels measured exceeds the permissible standards, then mechanical trouble in the
machine is indicated.
Vibration in rotating machinery is most often caused by unbalance, defective
bearings, misalignment, or mechanical looseness. For this reason, the vibration
pickup should be mounted at or close to the machine bearing housing. If the bearing
housing of interest is not accessible, the sensor can be mounted on the machine
structure or support which is located as close as possible to the bearing.
If the vibration sensor cannot be attached using the stud-mount method, it can be
secured with a magnetic holder, or hand-held with or without an extension probe.
However, the measurable vibration frequencies will be reduced as explained in
Chapter III.
If the vibration is to be measured quickly at many places on the rotating machine,
then the sensor should be held by hand. If vibration measurements are required at
places not readily accessible, the extension probe may be attached to the sensor to
provide easier and safer access to these places.
This chapter contains instructions on setup of the instrument controls, and includes
general instructions on measuring vibration, determining the severity and dominant
frequency of the vibration, classifying the vibration, and step-by-step instructions on
in–placebalancing.
4.2 SETUP
1. Prepare the Vibration – SPIKE ENERGY Detector and accessories for
operation as instructed in chapter III.
2. Set the instrument POWER SWITCH to ON.
3. Set the MODE SELECTOR SWITCH to the desired units.
4. Set the AMPLITUDE SELECTOR SWITCH to the desired full-scale
Range.
NOTE:
Initially the Amplitude Selector should be set to the least
sensitive range, and then progressively rotated to more
sensitive ranges until the level of vibration indicated on the
Amplitude Meter is 1/3rd of the Full Scale Value or greater.
Instructions on correctly reading the meter scales for various
ranges of amplitude are included in Chapter 3.

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4.3 VIBRATION MEASUREMENT
The vibration should be measured in the vertical, horizontal and axial planes of each
bearing housing. The vibration levels are then indicated on the AMPLITUDE METER.
All pertinent rotating machine information, along with the vibration readings, should
be recorded on a datasheet similar to the one shown in Figure 6. The recorded data
is used to determine the general operating condition of the machine. The data sheet
also provides a permanent record of the machine condition.
Figure 6 A typical vibration measurement datasheet
4.4 DETERMINING VIBRATION SEVERITY
Vibration measurements without a standard for comparison are seldom of any use.
There needs to be some guide to show how much is too much. Table 4, provides a
guide for Machine Tool Vibrations. The values listed merely indicate the range in
which satisfactory parts have been produced. Actual tolerances must be determined
by your own experience as to what vibration levels permit the meeting size and finish
tolerance.
For general machinery, the vibration severity chart shown in Figure 7 may be used.
Please note that vibration displacement and vibration acceleration values are for a
specific frequency of vibration while velocity readings may be used regardless of the
frequency.

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Table 4 Tentative guide to vibration tolerances for machine tools
Displacement of vibration as read
Type of machine with pickup spindle bearing housing
in the direction of cut
Grinders ToleranceRange
Thread Grinder 0.25 - 1.5 microns
Profile or contour Grinder 0.75 - 2.0 microns
Cylindrical Grinder 0.75 - 2.5 microns
Surface Grinder (Vertical Reading) 0.75 - 5.0 microns
Gardner or Besly type 1.25 - 5.0 microns
Centreless 1.0 - 2.5 microns
Boring Mill 1.5 - 2.5 microns
Lathe 5.0 - 2.5 microns
NOTE:
The above tolerance ranges consist of machine vibration
displacement values at which acceptable parts can generally be
produced and are supplied as a guide for judging the indicated
vibration as a warning of impending trouble. The measurements
were obtained with the vibration sensor mounted on the spindle
bearing housing in the direction of the machine cutting.
These values come from the experience of IRD personnel who have been trouble shooting
machine tools for over 10 years with the IRD equipment. They merely indicate the range in
which satisfactory parts have been produced and will vary depending upon size and finish
tolerance.
The units in which vibration severity may be measurement displacement, velocity or
acceleration – are interrelated to one another. Displacement is used for measuring the
condition of slower speed machinery, particularly where displacement standards have been
established or where excessive unbalance is present. However, Velocity measurements
provide a measure of the combined effects of vibration frequency as well as displacement
and can be universally applied regardless of machine speed or type of trouble. This type of
measurement provides a direct indication of the vibration severity and is generally the best
indicator of the machine balance or condition. Acceleration is generally used when vibration
occurs at high frequencies and often where the frequency of the source is many times the
shaft RPM.
The vibration amplitude should be obtained in velocity and in whatever other units are
desired. Measurements in displacement or acceleration will provide an indication of the
vibration severity only if the dominant frequency of the machine vibration is known. Since the
vibration velocity is consistent with rotational speed, vibration severity measured in terms of
vibration velocity is most common. If the vibration severity value read from the chart is too
high, then trouble may be indicated with the machines as explained in Section 4.5. As
already explained, acceleration as vibration severity parameter is used when vibration occurs
at many times shaft RPM, usually due to rolling element bearing excitation, gear defects or
aerodynamic problems such as cavitation. One such acceleration severity chart is shown in
Figure 8.

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©2008 IRD Mechanalysis Ltd
Figure 7 A general machinery vibration severity chart (Metric)
The SPIKE ENERGY mode circuits are used for the detection of deteriorating and defective
rolling element bearings and gear teeth. These circuits are completely independent of those
which measure the RMS vibration components in the displacement, velocity or acceleration
modes. The SPIKE ENERGY signal level is indicated on the Digital Display for machine
which operates from 600 to 3600 RPM, a SPIKE ENERGY level of 0.5 g or higher (as
measured with the pickup hand-held and the extension probe attached) may indicate that the
corresponding bearing or gear is defective.
Whether or not the bearing or gear is defective must be verified by experience and
observation of the machine trends, since individual machines may have different vibration
response characteristics. The acceptable level of SPIKE ENERGY amplitude for machines
whose operating speed is outside the 600 to 3600 RPM range should also be developed
individually from comparisons to similar machines and from careful study of the vibration
amplitude trends of the machine.