BRUEL & KJAER 4294 User manual

Technical
Documentation
HEADQUARTERS: Brüel&Kjær Sound & Vibration Measurement A/S · DK-2850 Nærum · Denmark
Telephone: [phone] · Fax: [phone] · www.bksv.com · [e-mail]
Local representatives and service organisations worldwide
Calibration Exciter
Types 4294 and 4294-002
English BE0739–15
User Manual
ËBE-0739---GÎ

BE0739–15 April 2014
Calibration Exciter
Types 4294 and 4294-002
User Manual
From serial no. 2863100

Copyright 1984 – 2014, Brüel&Kjær Sound & Vibration Measurement A/S
All rights reserved. No part of this publication may be reproduced or distributed in any form, or
by any means, without prior written consent from Brüel&Kjær Sound & Vibration Measurement
A/S, Nærum, Denmark
Safety Considerations
This apparatus has been designed and tested in accordance with IEC 61010–1 and EN61010– 1
Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory
Use. This manual contains information and warnings which must be followed to ensure safe
operation and to retain the apparatus in safe condition. Special note should be made of the
following:
Safety Symbols
The apparatus will be marked with this symbol when it is important that you refer to the
associated warning statements given in the manual.
Protective Earth Terminal Hazardous Voltage
Explosion Hazard
The equipment is not designed to be used in potentially explosive environments. It should not be
operated in the presence of flammable liquids or gases.
Warnings
• Switch off all power to equipment before connecting or disconnecting their digital interface.
Failure to do so could damage the equipment.
• Whenever it is likely that the correct function or operating safety of the apparatus has been
impaired, it must be made inoperative and be secured against unintended operation.
• Any adjustment, maintenance and repair of the open apparatus under voltage must be
avoided as far as possible and, if unavoidable, must be carried out only by trained service
personnel.
• Do not dispose of electronic equipment or batteries as unsorted municipal waste
• It is your responsibility to contribute to a clean and healthy environment by using
the appropriate local return and collection systems
• Hazardous substances in electronic equipment or batteries may have detrimental
effects on the environment and human health
• The symbol shown to the left indicates that separate collection systems must be used
for any discarded equipment or batteries marked with that symbol
• Waste electrical and electronic equipment or batteries may be returned to your
local Brüel&Kjær representative or to Brüel & Kjær Headquarters for disposal

Contents
CHAPTER 1
Introduction......................................................................................................... 1
CHAPTER 2
Operation............................................................................................................. 3
2.1 Environment and Handling................................................................................... 3
2.2 Battery Installation and Replacement.................................................................. 3
2.3 Mounting a Transducer........................................................................................ 4
2.4 Basic System Calibration..................................................................................... 5
2.5 Transducer Sensitivity Check .............................................................................. 6
CHAPTER 3
Specifications..................................................................................................... 9
3.1 Compliance with Standards................................................................................. 9
3.2 Specifications..................................................................................................... 10
3.3 Dimensions........................................................................................................ 11
CHAPTER 4
Service and Repair........................................................................................... 13

1
Chapter 1
Introduction
USES
• Precise field calibration of vibration transducers
• Rapid calibration and checking of vibration transducer sensitivity
• Quick, easy field calibration of vibration measurement and recording systems
FEATURES
• Small, lightweight, and battery-driven
• Leather case for impact protection
• Designed for everyday use in harsh environments
• Acceleration, velocity and displacement calibration
• High-precision, crystal-controlled servo operating at 159.15 Hz (1000 rad s–1)
• Drop- and environment-tested according to IEC 60068
• Splash-proof according to IP 54 (IEC 60529)
Description
Type 4294 enables accurate adjustment of measuring instrumentation at a standard acceleration
level of 10 ms–2 (0 – 70 gram load). The reference signal can also be used for velocity and
displacement calibration at 10 mms–1 and 10 µm, respectively.
Type 4294-002 enables accurate adjustment of measuring instrumentation at a standard
acceleration level of 3.16 ms–2 (0 – 200 gram load). The reference signal can also be used for
velocity and displacement calibration at 3.16 mms–1 and 3.16 µm, respectively.
The calibrator contains an electromagnetic exciter driven by a crystal oscillator at a frequency
of 159.15 Hz (1000 rad s–1). A small accelerometer on the underside of the vibration table
provides servo feedback to maintain a constant, accurate vibration level independent of the
mass of the transducer under test (maximum 70 gram for Type 4294 and 200 gram for
Type 4294-002).

Calibration Exciter Types 4294 and 4294-002 – User Manual2
Fig.1.1
Calibration Exciter
Type 4294 in its leather
case
To prevent overload, power to the calibrator is automatically disconnected if a transducer mass
above 70 gram for Type 4294 or 200 gram for Type 4294-002 is mounted on the exciter’s
vibration table.
Use of the calibrator is straightforward. You can attach a transducer to the vibration table using
(see Fig.2.2):
• 10 – 32 UNF Steel Stud YQ-2962
• 10 g Mounting Disc DB-2996 (supplied) for transducers:
– with 3 mm threads
– fitted with Mounting Magnet UA-0642
– mounted with beeswax
Note:
Mounting using adhesive is not recommended.
To switch the calibrator on, press the small button on the side of its housing.
After system adjustment, turn the calibrator off by pressing the button again.
To prolong the battery life, the exciter automatically switches off after approximately
100 seconds.

3
Chapter 2
Operation
2.1 Environment and Handling
Calibration Exciter Type 4294 is designed for use in environments at temperatures within the
range –10 to +55°C (+14 to +131°F) and with relative humidity up to 90% RH (30°C (86°F),
non-condensing). Whenever possible, the exciter should be used in its leather case (see
Fig.1.1) to protect it from mechanical damage and contamination from grease or dirt.
2.2 Battery Installation and Replacement
For powering Type 4294, a long-life alkaline battery QB-0016 (IEC Type 6LR61) is
recommended. The battery fits into the battery holder, which is accessible after unscrewing the
base of the calibrator (see Fig.2.1). To prevent damage, take care not to cross the screw thread
on reassembly.
To maximise battery life, Type 4294 automatically switches off after approximately 100 s.
Using Battery QB-0016, approximately 200 calibrations, each of approximately 100 s, are
possible. After this, the operating period rapidly decreases, indicating that the battery needs to
be replaced. However, the exciter can be used until its battery is fully depleted without
influencing the accuracy of the reference level generated.
Fig.2.1 9 V battery installed in the calibrator

Calibration Exciter Types 4294 and 4294-002 – User Manual4
2.3 Mounting a Transducer
Types 4294 and 4294-002 are designed for use with Brüel & Kjær Accelerometers with
maximum weights of 70 and 200 grams, respectively. The accelerometers can be mounted with
“finger-tight” mounting torque (~0.3 Nm, max. 0.5 Nm) directly onto the vibration table using
a 10–32 UNF steel stud YQ-2962, or mounted with the aid of Mounting Disc DB-2996 for
transducers weighing less than 10 grams. Different mounting options are illustrated in Fig.2.2.
Caution:
If the specified torque is exceeded, be sure to apply a similar counter-torque to the armature in
order to protect the vibration table from damage
The mounting disc lets you attach accelerometers in several ways. Small transducers fitted with
3 mm threads can be attached using 3 mm Steel Stud YQ-2007. Alternatively, a Mounting
Magnet UA-0642 or Beeswax YJ-0216 can be used to attach transducers to the mounting disc.
Fig.2.2 Transducer mounting options
4294 or 4294-002
Calibration Exciter
Accelerometer
with Integral
10-32 UNF Stud
10-32 UNF
Threaded
Accelerometer
10-32 UNF
Threaded
Accelerometer
M3 Threaded
Accelerometer
Accelerometer
with Integral
M3 Stud
Accelerometer
without
Base Thread
¼-28 UNF
Threaded
Accelerometer
10-32 UNF
Mounting Thread
YQ-2962
10-32 UNF Stud
UA-0642
Mounting
Magnet
YQ-2007
M3 Stud
YJ-0216
Beeswax
UA-2062
¼-28 UNF to
10-32 UNF Stud
DB-2996 Mounting Disc
(3 mm tapping, 10-32 UNF thread)
+
Z
+
140090