Phase calculation with tacho
Phase calculation with tacho
(OP)
Hi there,
Can somebody provide a guidance on how to calculate the phase between a vibration measurement channel and the tacho?
I guess people won't use any time domain calculation method to do such calculation. Time domain signals may have noise, and we want to calculate the phase not only at fundemental frequencies, but also the harmonics.
Should we use cross spectrum method? How the tacho signal, which is essentially a chain of pulses, be represented?
Thanks for the attention.
James
Can somebody provide a guidance on how to calculate the phase between a vibration measurement channel and the tacho?
I guess people won't use any time domain calculation method to do such calculation. Time domain signals may have noise, and we want to calculate the phase not only at fundemental frequencies, but also the harmonics.
Should we use cross spectrum method? How the tacho signal, which is essentially a chain of pulses, be represented?
Thanks for the attention.
James
www.go-ci.com
8ch dynamic signal analyzer/recorder
102.4 kHz sampling, 130dB dynamic range





RE: Phase calculation with tacho
It could be used to drive an ODS animation, for example.
Another alternative would be to use phase locked triggering.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Phase calculation with tacho
- Steve
RE: Phase calculation with tacho
Steve, I am trying to measure the phase of an analog channel in reference to the tacho input. It is used for rotor balancing. Estimating the RPM value is not sufficient. We need to know the relative phase info.
James
www.go-ci.com
8ch dynamic signal analyzer/recorder
102.4 kHz sampling, 130dB dynamic range
RE: Phase calculation with tacho
It will work 100% for first order two plane balancing, I've done it tens, or maybe hundreds, of times.
For first order you'll need to use a 1 pulse per rev tacho, obviously. If you can't get one of the crank use a proximity probe on a cam and that'll give you half pulse per rev.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Phase calculation with tacho
www.go-ci.com
8ch dynamic signal analyzer/recorder
102.4 kHz sampling, 130dB dynamic range