Accelerometers

Tandem-Piezo design – the benefits

The unique features of PRUFTECHNIKs patented Tandem-Piezo accelerometers make them suitable for virtually all areas of applications in industrial environments.

The unique design practically eliminates temperature shock and base strain effects; it also handles condition evaluation of turbo machinery and gearboxes, anti-friction bearings and pump cavitation – all with the same transducer, thanks to a wide linear range and a defined shock pulse resonance characteristic at 36 kHz.

The built-in current line drive amplifier ensures immunity to ground looping and extremely low signal loss, even over long transmission distances, as well as compatibility with the entire PRUFTECHNIK line of mobile data collectors, FFT analyzers and online or remote condition monitoring equipment.

Despite the technologically advanced tandem-piezo design, these sensors are more economical than conventional compressor sensors.

Tandem-Piezo accelerometer at a glance:

Current Line Drive (CLD) – the advantages

The long cables used in permanently installed monitoring systems must stand up to considerable electrical and mechanical interference. With traditional sensors the signals barely get through the network, being drowned out by the noise and interference.

The solution: use either expensive high-quality cable carefully laid away from interference sources or a ‘line drive’ system, which consists of a tiny electronic amplifier built into each sensor which boosts the vibration signal.
The latter offers several advantages:

There are two types of line drive systems, providing either voltage output or current output. PRUFTECHNIK systems use the latter, since it is a superior system with more sophisticated electronics and the following significant advantages:

High frequency loss in long cables

The PRUFTECHNIK current line driver system has much lower high frequency loss in long cables than voltage output systems. This is because the instrument has a significantly lower input impedance, and since the maximum frequency is inversely proportional to input impedance, the maximum frequency is greatly extended.

Ground looping and noise

The PRUFTECHNIK current line driver system has much lower susceptibility to induced noise and ground-loop noise than voltage output systems. This is because the very low instrument input impedance minimizes influence from electromagnetic fields. The instrument virtually ‘shorts’ the cable conductors. This has the added advantage that, with the exception of frequency rectifier-governed motors and high-voltage motors, costly insulated sensors can be avoided, eliminating the problem of insulator capacitance.