Shock Accelerometer
Page 1
002-096e-01.19
Instruction Manual
Shock Accelerometers
Type 8742A…
CE
Kistler Instrument , 75 John Glenn Drive , Amherst, NY 14228-2171,
Tel: 716-691-5100
Page 1: ...002 096e 01 19 Instruction Manual Shock Accelerometers Type 8742A...
Page 2: ...Shock Accelerometer Page 1 002 096e 01 19 Instruction Manual Shock Accelerometers Type 8742A CE Kistler Instrument 75 John Glenn Drive Amherst NY 14228 2171 Tel 716 691 5100...
Page 3: ...curing Cables 9 6 Operation 10 6 1 Powering 10 6 1 1 Using Built In Power Sources 10 6 1 2 Kistler Couplers 11 6 1 3 The Constant Current Power Supply Coupler 11 6 1 4 Sensor Power Up 14 6 1 5 Overloa...
Page 4: ...instructions carefully before installing and operating these instruments Kistler offers a wide selection of measuring instruments and comprehensive systems including Sensors for force pressure accele...
Page 5: ...ry area Keep the connector clean and covered when not in use Exercise care during cable connection Cable connector center pin should align with the female receptacle on the accelerometer Follow the re...
Page 6: ...ccelerometers are shear mode shock and vibration measuring instruments These units are intended for pyroshock testing metal to metal impact studies drop testing etc A self generating piezoelectric sen...
Page 7: ...material to produce an electric charge Since force is mass times acceleration from Newton s second law the charge produced is proportional to acceleration since m is constant This is represented by T...
Page 8: ...r 4 Cable 5 Readout or analysis equipment 6 Installation 6 1 General For proper operation of shock accelerometers care must be taken during the installation process Careful installation will result in...
Page 9: ...re that the base of the accelerometer makes full contact with the mounting surface See table 3 2 Completely clean the surface prior to mounting 3 Apply a thin coat of silicon grease to both the accele...
Page 10: ...1 2 minimum 28 UNF 0 22 5 6 0 42 10 7 Table 3 Mounting Surface Preparation 6 4 Securing Cables Figures 4 and 5 show the correct and incorrect ways for installing cables Allow a sufficient radius to en...
Page 11: ...7 1 1 Using Built In Power Sources Many FFT analyzers and vibration monitors are available with internal accelerometer power supplies Often identified as Constant Current Sources these internal power...
Page 12: ...Type 5114 plus front panel adjustable gain and filter provision 5148 16 channel rack mountable AC powered coupler with unity gain LEDs indicate circuit integrity Front panel BNC output connectors 5165...
Page 13: ...7 shows a schematic of a simple power supply coupler for shock accelerometers DC power is supplied from a 24 volt source such as a regulated power supply or batteries One advantage of the Piezotron s...
Page 14: ...Es 1 Eb Maximum negative amplitude Fs Eb 2 Where Fs Full scale output peak ES DC supply voltage sometimes called compliance voltage Eb bias voltage from calibration certificate Figure 8 Output Signal...
Page 15: ...ing range certain components will become non operational During this non operational state the amplifier components are protected from overload damage The amount of time required for recovery from an...
Page 16: ...he cable capacitance becomes significant thereby loading the Piezotron impedance converter If the current is not sufficient to charge the cable at an adequate rate high frequency distortion will be ex...
Page 17: ...creased the noise produced by the Piezotron circuit will also increase The miniature Piezotron amplifier will produce more heat as current is increased resulting in reduced life and reliability The sp...
Page 18: ...ed reference frequency over a specified bandwidth Shock accelerometers are specified with maximum variations of 5 to 10 Kistler uses the industry standard reference frequency of 100Hz Many users may b...
Page 19: ...ition will occur per the above equation which causes the sensitivity to increase with frequency It is desirable to have a uniform frequency response over the specified frequency range As can be seen F...
Page 20: ...cer The low frequency response of accelerometers is an electrical limitation The design of shock accelerometers is such that low frequency drift caused by temperature variations is virtually eliminate...
Page 21: ...ncy is the reciprocal of time The low frequency limit of shock accelerometers is defined as the point where the response is 5 also 10 where specified below the reference point 100 Hz The low frequency...
Page 22: ...by providing optimal low frequency response When using a simple coupler circuit Figure 7 with AC coupling a time constant equal to the product of the decoupling capacitor s C capacitance times the rea...
Page 23: ...onitor as follows A With the accelerometer connected check for a normal reading on the bias indicator normal should be around 11 VDC B If the bias reading is high 1 Disconnect the accelerometer at the...
Page 24: ...cturer s product data for recommended removal agent Do not us an abrasive on the base surface This can affect the flatness thereby reducing high frequency transmissibility 8 5 Calibration Calibration...
Page 25: ...Premium industrial cable connector 10 32 pos to BNC pos 1761sp x General purpose cable connector 10 32 pos to BNC pos 1762sp x General purpose cable connector 10 32 pos to BNC pos 1601Bsp BNC pos to...
