B&K 2625, Instructions And Applications

Page 1: ...eamplifier Type 2625 A fully transistorised preamplifier of modular design for vibration measurements Integration networks are included to give an output proportional to acceleration velocity or displ...

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Page 3: ...Vibration Pick up Preamplifier Type 2625 Reprint february 1970...

Page 4: ...4 Rear pane l 6 2 5 Module System 0 0 6 2 6 Input Characteristics 10 2 7 Frequency Characteristics 0 0 0 11 2 8 Output Characteristics 12 2 9 Sensitivity 12 2 10 Distortion 12 2 11 Noise 13 3 Operati...

Page 5: ...ocket at the back A field effect transistor stage in the input circuit gives extremely high input impedance variable from about 3000 MQ at zero gain to about 450 MQ at 20 dB gain The preamplifier has...

Page 6: ...s ACCELERATION VELOCITY DISPLACEMENT This knob selects the integra tion networks In the ACCELERATION position no integrating networks are connected Three velocity and six displacement positions are po...

Page 7: ...nsitivities from 1 to 10 mV g can be scaled to 10 mV g and those with sensitivities from 10 to 100 mV g can be scaled to 100 mV g Also in the input stages is a capacitive attenuator which gives 40 dB...

Page 8: ...t shown in Fig 2 3 The compartment is accessible by removing the top screw on the rear of the equipment Fig 2 4 and sliding the top panel backwards 3 X 9 V batteries are required size 25 5 X 48 5 mm I...

Page 9: ...n fits into the wooden case KA 0020 making a portable instrument system Standard 19 rack mounting is simple using the rack mounting lugs which are screwed onto the case KK 0010 A three tier system is...

Page 10: ...Fig 2 5 The 8 K module system 8...

Page 11: ...2500 2000 1500 1000 500 0 Fig 2 6 Mounting of module Input Resistance 2 4 6 8 10 12 14 16 18 20 dB J Gain 7 fL7 Fig 2 7 Input impedance as a function of gain setting 9...

Page 12: ...input resistance is R this will give a lower limiting frequency t of nC R At 20 dB gain with a source capacity of 1000 pF this gives f 0 3 Hz Hence for low frequency measurements it may be an advanta...

Page 13: ...citive loading in position ACCEL without power amplifier 10 Output Voltage RMS 2 0 1 0 01 10 102 5 10 3 A 1 5 10 Freoqueoncy Hz 10 Limit for negligible distortion 0 dB gain setting Fig 2 11 Limit of h...

Page 14: ...e power amplifier In these positions the maximum output voltage and current is 7 V 2 3 rnA thus reducing the loading restriction considerably as shown in Fig 2 11 2 9 Sensitivity As explained under IN...

Page 15: ...ig 2 13 Total noise in the range 20 Hz to 40 kHz appears at the right hand end of the scale marked Lin Total noise when weighting networks A B C are em ployed also appear here ooooooooccccccooooooooco...

Page 16: ...ntioned in section 2 9 Long cables on the output will also affect the high frequency response as shown in the curves of Fig 2 9 and 2 10 Note that since the outputs are directly coupled it may be nece...

Page 17: ...h tools and instruction for mounting of the plugs on cable UA 0130 1 2 m 4 ft of mininoise cable for operation to 100 C 212 F fitted with miniature plugs Individually calibrated AO 0038 1 2 m 4 ft of...

Page 18: ...oiit r svrt aceot c ntr e insulation isgra Miteciiatea Clea __ x osed insulatiOilto l r vent leakage 16...

Page 19: ...30 Hz 3Hz 100 Hz 10Hz 300Hz 30Hz 1000 Hz 100 Hz 3000 Hz 300 Hz 10000 Hz Variable 0 to 20 dB and 40 to 20 dB Max 20 11 V from 2 Hz 40 kHz with 1 nF across input referred to input Integration Networks...

Page 20: ...e Union Carbide Ever Ready No 216 Hellesen Type H 10 Varta Pertrix No 438 Tudor No 4 T4 National U 006P excluding knobs and feet Height 132 6 mm 5 22 ins Width 61 mm 2 40 ins Depth 200 mm 7 87 ins 820...

Page 21: ...pos 40 dB 4332 4334 7000 g peak 7 1 4 m sec2 peak 4333 4335 10000 g peak 10 1 4 m sec2 peak 4339 4343 1 g peak 10 1 4 m sec2 peak 4344 14000 g peak 14 1 4 m sec2 peak 4338 2000 g peak 2 1 4 m sec2 pea...

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Page 24: ...Accelerometer Preamplifiers Accelerometer Calibrators Vibration Meters Magnetic Transducers Capacitive Transducers Vibration Exciter Controls Vibration Programmers Vibration Signal Selectors Mini Sha...