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Difference between revisions of "NVGate Torsional"
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Overview | Overview | ||
=== Frequency to RPM converter (Torsional inputs)=== | |||
On reciprocating machinery (diesel engine, pump) or any acyclic rotating devices (generator, | On reciprocating machinery (diesel engine, pump) or any acyclic rotating devices (generator,compressor), the cause of vibrations often comes from the non-linearity of the angular speed. The analysis of the instantaneous angular speed inside each shaft revolution provides essentialinformation. Such information are helpful for vibrations reduction during prototyping or evenfor source identification while doing service diagnostics.<br> | ||
compressor), the cause of vibrations often comes from the non-linearity of the angular speed. | |||
The analysis of the instantaneous angular speed inside each shaft revolution provides | The common way to measure such instantaneous velocity is to install a coding wheel or a rotary encoder on the shaft. Then the rate of pulse delivered by such device is directly proportional to the RPM speed during the last pulse interval. This type of measurement needs a specific conditioner(usually an external box) which transforms the pulses train in a continuous voltage proportional to the RPM.<br> | ||
Such devices are expensive, lead to more cable, are oftenlimited to 2 probes and so on. But the main inconvenience is the phase error they introducedue to their internal response time.<br> | |||
The common way to measure such instantaneous velocity is | |||
to install a coding wheel or a rotary encoder on the shaft. | |||
Then the rate of pulse delivered by such device is directly | |||
proportional to the RPM speed during the last pulse interval. | OROS propose an integrated frequency to RPM converter which avoidsthe above-mentioned inconveniences.<br> | ||
This type of measurement needs a specific conditioner | |||
(usually an external box) which transforms the pulses train in | This option transforms each external Synch input in afrequency to RPM converter (allows handling up to 6 torsional/acyclic inputs at a time). This integrated converter benefits of the high accuracy of the 3-Series analyzers Ext. synch inputs (over sampled up to 6.4 MHz). As a matter of fact the sampling of such pulse rate must bevery accurate in order to avoid speed jitter on the result. | ||
a continuous voltage proportional to the RPM. | |||
Such devices are expensive, lead to more cable, are | |||
OROS propose | |||
integrated converter benefits of the high accuracy of the 3-Series analyzers Ext. synch inputs | |||
(over sampled up to 6.4 MHz). As a matter of fact the sampling of such pulse rate must | |||
The ext. synch input can be used as a: | The ext. synch input can be used as a: | ||
1. Trigger -> provides edge detection events | 1. Trigger -> provides edge detection events | ||
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3. Torsional converter (option) -> provides | 3. Torsional converter (option) -> provides | ||
instantaneous RPM as a signal. | instantaneous RPM as a signal. | ||
By selecting the third option (Torsional) in the | By selecting the third option (Torsional) in the ModeSetting, the ext. synch is made available as a standard inputproviding the RPM signal.The other settings to update are: | ||
The other settings to update are: | |||
· the number of pulses/rev. | · the number of pulses/rev. | ||
· Average size which acts as rpm smother when the | · Average size which acts as rpm smother when the | ||
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Pulses train | Pulses train | ||
Converted RPM | Converted RPM | ||
· At least the filter which let you integrate or differentiate the RPM speed to | · At least the filter which let you integrate or differentiate the RPM speed to getrespectively plane angle deviations and angular accelerations for the analyses. | ||
==Analyses== | |||
Analyses | |||
The instantaneous signals are available for numerous analyses. The main tow ones are: | The instantaneous signals are available for numerous analyses. The main tow ones are: | ||
· The non cyclic behavior of a shaft which is analyzed by the order analysis processing | · The non cyclic behavior of a shaft which is analyzed by the order analysis processing providing order profiles and the time domain analysis for in revolution RPM profiles. | ||
providing order profiles and the time domain analysis for in revolution RPM profiles. | · The torsional behavior of a shaft (crankshaft, alternator) or a driving belt (service belt) being excited by its acyclic motion. In such a case the phenomena are analyzed order by order using the cross-phase tracking capabilities of the SOA Plug-in. In this case 2 or | ||
· The torsional behavior of a shaft (crankshaft, alternator) or a driving belt (service belt) | more torsional inputs are used: in different location of the shaft or on each pulley driven by the belt. | ||
being excited by its acyclic motion. In such a case the phenomena are analyzed order by | |||
order using the cross-phase tracking capabilities of the SOA Plug-in. In this case 2 or | ====On-line==== | ||
more torsional inputs are used: in different location of the shaft or on each pulley driven | In the on-line mode the torsional inputs appear as additional in the channels connection dialog box. They are identified as Tors. x from the Signal Op. resource (not visible in the ASB). These signals can be dispatched exactly as the standard inputs ones; recorded, analyzed and monitored with the TDA plug-in. | ||
by the belt. | The torsional inputs may be recorded as it or the source pulses can be recorded also. | ||
On-line | ===Post-processing==== | ||
In the on-line mode the torsional inputs appear | |||
as additional in the channels connection dialog | |||
box. They are identified as Tors. x from the | |||
Signal Op. resource (not visible in the ASB). | |||
These signals can be dispatched exactly as the | |||
standard inputs ones; recorded, analyzed and | |||
monitored with the TDA plug-in. | |||
The torsional inputs may be recorded as it or the | |||
source pulses can be recorded also. | |||
Post-processing | |||
For post-analysis purposes, the way to operate depends on the type of recorded signal: | For post-analysis purposes, the way to operate depends on the type of recorded signal: | ||
· If the converted signal (Tors x) have been recorded, the post analysis is exactly like for | · If the converted signal (Tors x) have been recorded, the post analysis is exactly like for the usual recorded inputs: | ||
the usual recorded inputs: | · if the pulses have been recorded and not the converted signal, a new resource module called Signal Operation is then available for this conversion. | ||
· if the pulses have been recorded and not the converted signal, a new resource module | |||
called Signal Operation is then available for this conversion. | · The conversion setup is available from the ASB. It is identical to the on-line one: | ||
· At least the Tors. x signal (converted to angular velocity (or acceleration or deviation) is available from the track connection dialog: | |||
· The conversion setup is available from the ASB. It is | ==Specifications== | ||
identical to the on-line one: | The FVC option features the following main specifications:<br> | ||
· At least the Tors. x signal (converted to angular | |||
velocity (or acceleration or deviation) is available from | · Number of pulses/rev: 1 to 4096<br> | ||
the track connection dialog: | |||
Specifications | · Max pulse frequency: 40 kHz 64 times oversampled, <br> | ||
The FVC option features the following main specifications: | |||
· Number of pulses/rev: 1 to | · Max angular speed:<br> | ||
· Max pulse frequency: 40 kHz, | |||
· Max angular speed: | Max RPM = (40 000*64)/pulse per revolution exemple : 12 800 RPM with 200 Pls/rev<br> | ||
RPM | · Missing teeth management: up to 3 consecutive teeth.<br> | ||
/ | |||
· Available filters: HP, LP; BP, SB, Int, double Int, differentiation<br> | |||
· Missing teeth management: | |||
· Available filters: HP, LP; BP, SB, Int, double Int, differentiation | |||
===Angular sampling for SOA analysis=== | ===Angular sampling for SOA analysis=== | ||