Thread Tools
Mar 07, 2013, 04:35 PM
Gorilla Glue Expert
PikeStaff's Avatar
In 4 point, I frequently cannot get a beautiful, smooth, uniform sine wave nor a single reference spike on the scope. Indicative of a need for more care in the mount?
Sign up now
to remove ads between posts
Mar 07, 2013, 04:56 PM
Registered User
Yes and possibly no.....

Check the Spectrum, note that....
Hold the fan in your hand and check it again.....
If the mount adds a lot of 'noise' (other freqs) then it is probably not done well.
eg if you even had a great mount, but placed its hard base right onto a hard table, you will get reflective waves and thus noise.
So if the cradle did have a lot of noise, make sure it is on a SOFT base (fold a towel in half 8 times or something)
If it STILL has a lot of noise after that... then it is coming from the motor all but surely.

Holding it in your hand is a great 'deadener', so that gives you a refecence of what it COULD be like in a good mount.
You could do all tests in your hand too really BUT, because it is not a consistent thing - you could hold it firmer etc - and because it is that 'great deadener' it detracts from sensitivity - it is not the best idea to use (but could be still used).

Then the 'On a folded towel' "mount"..... that has a very good level of 'float on a cloud' as fans are quite light, relative to the vibration levels we need to sense, and it also gives a good 'soft hold' on the fan - which is half good, half bad. Good as it dampens the extra noises/refelctions etc. Bad because it lso dampens the real Vibe a bit.
But in my testing of 'great cradle' versus ' folded towel', the cradle only wins out by a small amount, and the the same balancing accuracy can be achieved by both anyway.

EXCEPT. after I began mounting the Acc sensor at the bar END... which means it has more leverage and thus is more sensitive..... AND for some reasons also dampens out the noise freqs better too, but not the main vibe freq much at all ! So that way is a clear winner.
Cradle... with Acc sensor VERTICAL at the bar end. And my cradle bar is something like 100mm long.... so that gives it a good length to amplify (via leverage) the vibration.
Vertical is fine, and better, because the bar pivot (and whole physical layout of things) means the end of the bar is affected in the vertical direction by the fans major vibration direction. (The pivot effectively 're-vectors' vibration forces 90deg)

But as mentioned, the 'folded towel' also works totally fine. (I think I have eight layers, after all the 'half folds' down to that size)
Mar 07, 2013, 05:04 PM
Registered User
Oh... a GREAT idea is to learn and UNDERSTAND what is actually being done, and how etc.
So then you can real-time work out reasons for things.
Knowing things at "building block" levels means you can work out ANYTHING about that system, but is also great because those 'building blocks' (and from many other things you ever make that effort to learn and understand) allow you to apply them to many many other real-world things. And then the same thing.... knowing that means you can work out reasons in YOUR situation, that just passing 'apparent' information to someone else can never match. (But still better than nothing, and needs to be done if you yourself did not know more about it).

You can compare those 'building blocks' to Lego...... there are only so many different blocks..... and they can make a million things.....
So knowing those base blocks means YOU can "know a million things" too!

Also in this specific case.... to get to the final 'fantastic balance' level, you will need to KNOW some of those important 'how it works' aspects. So you can real-time do the right/appropriate things.
Mar 07, 2013, 06:04 PM
Good vibrations.
dynexhobby's Avatar
It would be great to see some photo's of the setup and scope plots. That way we can comment on what is happening. Getting a beautiful sine wave is not always possible especially if you are getting noise from other sources.

Quote:
Originally Posted by PikeStaff
In 4 point, I frequently cannot get a beautiful, smooth, uniform sine wave nor a single reference spike on the scope. Indicative of a need for more care in the mount?
Mar 07, 2013, 07:24 PM
Gorilla Glue Expert
PikeStaff's Avatar
Quote:
Originally Posted by dynexhobby
It would be great to see some photo's of the setup and scope plots. That way we can comment on what is happening. Getting a beautiful sine wave is not always possible especially if you are getting noise from other sources.
Gotcha! I promise that, over the next couple of days, I'll get those pics posted up on here. It has become very, very apparent that the capabilities here are very, very real - and that to take advantage of them, one needs to re-learn just how ham-handed one has become over the years . Finesse and grace do have a place, after all......
Mar 07, 2013, 07:36 PM
Gorilla Glue Expert
PikeStaff's Avatar
Quote:
Originally Posted by PeterVRC
Oh... a GREAT idea is to learn and UNDERSTAND what is actually being done, and how etc.
So then you can real-time work out reasons for things.
Knowing things at "building block" levels means you can work out ANYTHING about that system, but is also great because those 'building blocks' (and from many other things you ever make that effort to learn and understand) allow you to apply them to many many other real-world things. And then the same thing.... knowing that means you can work out reasons in YOUR situation, that just passing 'apparent' information to someone else can never match. (But still better than nothing, and needs to be done if you yourself did not know more about it).

You can compare those 'building blocks' to Lego...... there are only so many different blocks..... and they can make a million things.....
So knowing those base blocks means YOU can "know a million things" too!

Also in this specific case.... to get to the final 'fantastic balance' level, you will need to KNOW some of those important 'how it works' aspects. So you can real-time do the right/appropriate things.
I have learned a great many things, over these past 60 years; some I wanted to know, some that could have been OK to not know. I will never be a vibrations expert - I had enough calculus in engineering school to firmly determine that this was a life I would not cleave to. Nor, for that matter, will I ever be an electronics expert; some things are just better left to those who genuinely enjoy those pursuits, in lieu of forcing the knowledge into heads that prefer other interests.

Count me as one of those with passing interest of the fine details here . It is results I crave, with somewhat less interest in how to get them. Going back to school, so to speak, seems about as pleasant as root canal work to me these days. So, while there is - without question - substantial benefit in deriving true fundamental knowledge of the subject at hand, it would entail far more effort than I am presently inclined to commit..
Mar 10, 2013, 09:14 PM
Good vibrations.
dynexhobby's Avatar
Don't lose faith in the process

There was a lot of R&D that went into this and to be honest I wouldn't expect anyone to know the theory of balancing. Enough info is there to assist you through the process. It does help if you understand the basic's of balancing and measuring good data. Good measurements will lead to good results, but keep in mind that noise can creep in that can throw you off the solution. You will recognize this in good time.

good luck

DH


Quote:
Originally Posted by PikeStaff
I have learned a great many things, over these past 60 years; some I wanted to know, some that could have been OK to not know. I will never be a vibrations expert - I had enough calculus in engineering school to firmly determine that this was a life I would not cleave to. Nor, for that matter, will I ever be an electronics expert; some things are just better left to those who genuinely enjoy those pursuits, in lieu of forcing the knowledge into heads that prefer other interests.

Count me as one of those with passing interest of the fine details here . It is results I crave, with somewhat less interest in how to get them. Going back to school, so to speak, seems about as pleasant as root canal work to me these days. So, while there is - without question - substantial benefit in deriving true fundamental knowledge of the subject at hand, it would entail far more effort than I am presently inclined to commit..
Mar 10, 2013, 09:20 PM
Registered User
DamonH's Avatar
DH, I tried your suggestion of shaking sensor in my hand and it kinda seemed to work intermittently and I had to shake it somewhat hard to make it work. Could there possibly be something wrong with my sensor? What did you mean by "if it didn't work it may not be set up right? Thanks.
Mar 10, 2013, 09:48 PM
Good vibrations.
dynexhobby's Avatar
By setup, I'm referring to the sensor not being calibrated correctly or the gain being turned down too low. Also can you check your PCB and let me know if the "jumper" is attached next to the "trigger" dial?

Quote:
Originally Posted by DamonH
DH, I tried your suggestion of shaking sensor in my hand and it kinda seemed to work intermittently and I had to shake it somewhat hard to make it work. Could there possibly be something wrong with my sensor? What did you mean by "if it didn't work it may not be set up right? Thanks.
Mar 10, 2013, 09:51 PM
Gorilla Glue Expert
PikeStaff's Avatar
Quote:
Originally Posted by dynexhobby
Don't lose faith in the process

DH
Never. That will not happen.

Simply getting to the point of putting this unit out, into a public market, speaks volumes of the understanding and focused effort put into its presentation. Truly volumes.

There is huge faith in these old bones of the ability of this devise, particularly when applied with diligence - I have seen some of it already, and you may be certain that I have not - yet, anyway - zeroed in on demanding non-speculative results. Honestly, I have been so delighted with the magnitude of my sloppy efforts that I have been wide-eyed with possibility.....which will come with escalating understanding and effort.

But right now, the use of the scope with the Dynex is blowing me out of the water - awesome potential. It has already smoothed out a heretofore miserable unit, with virtually no effort and time. Which will drive that desire for more, big-time.......but not right now.

I am just having too much fun with it for that level of intensity .
Mar 11, 2013, 07:07 AM
Registered User
DamonH's Avatar
Quote:
Originally Posted by dynexhobby
By setup, I'm referring to the sensor not being calibrated correctly or the gain being turned down too low. Also can you check your PCB and let me know if the "jumper" is attached next to the "trigger" dial?
Yes, there seems to be a jumper next to trigger dial labeled PRGMJ. As far as cal, I cal'd the sensor to almost .000mv and tried the gain dial in just about every position to include all the way up.
Mar 11, 2013, 04:22 PM
Good vibrations.
dynexhobby's Avatar
OK there are two things you can try,

1. When you turn the unit on does the "green" light appear? if yes then that the unit is working fine.

2. When you press the red push button, does the "yellow" light appear for strobing? Also does the strobe blink twice? If yes then that the unit is working fine.

3. When you setup for strobing, set the trigger dial to "6". The sensitivity neutral point is at "6", either side of this value will change the sensitivity of the circuit.

4. Check wiring to the accelerometer make sure its not broken. Is the accelerometer connected to the "Acc1" port?

If you have any further issues send me an email at info@dynexhobby.com

cheers

DH


Quote:
Originally Posted by DamonH
Yes, there seems to be a jumper next to trigger dial labeled PRGMJ. As far as cal, I cal'd the sensor to almost .000mv and tried the gain dial in just about every position to include all the way up.
Mar 11, 2013, 09:10 PM
Registered User
DamonH's Avatar
Quote:
Originally Posted by dynexhobby
OK there are two things you can try,

1. When you turn the unit on does the "green" light appear? if yes then that the unit is

2. When you press the red push button, does the "yellow" light appear for strobing? Also does the strobe blink twice? If yes then that the unit is working fine.

3. When you setup for strobing, set the trigger dial to "6". The sensitivity neutral point is at "6", either side of this value will change the sensitivity of the circuit.

4. Check wiring to the accelerometer make sure its not broken. Is the accelerometer connected to the "Acc1" port?

If you have any further issues send me an email at info@dynexhobby.com

cheers

DH
When I turn unit on red on light comes on and yellow PC light is on. When I press red button yellow PC light goes off and strobe light flashes twice. After a few seconds green strobe light comes on and strobe glows steady.

Thanks.
Mar 11, 2013, 09:25 PM
Good vibrations.
dynexhobby's Avatar
OK, I've seen this once before. The issue was that the red button didn't remain in the down position (i.e. it popped back up). If this occurs the micro-controller doesn't get the signal from the accelerometer and triggers the strobe constantly. The button must remain down an locked to strobe.

Quote:
Originally Posted by DamonH
When I turn unit on red on light comes on and yellow PC light is on. When I press red button yellow PC light goes off and strobe light flashes twice. After a few seconds green strobe light comes on and strobe glows steady.

Thanks.
Mar 11, 2013, 09:38 PM
Registered User
DamonH's Avatar
Quote:
Originally Posted by dynexhobby
OK, I've seen this once before. The issue was that the red button didn't remain in the down position (i.e. it popped back up). If this occurs the micro-controller doesn't get the signal from the accelerometer and triggers the strobe constantly. The button must remain down an locked to strobe.
The button does click and stay down. The strobe does flash when I adjust the knob. It just seems to me like the sensor isn't very sensitive. When I just put sensor in my hand and shake I really have to shake it pretty good to make the strobe respond. I wonder if there isn't something wrong with my sensor?


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question EDF Impeller Balance old_dude Electric Ducted Fan Jet Talk 8 Nov 16, 2012 04:24 AM
For Sale Optical EDF Balancer for sale yakhakker Aircraft - Electric - Jets (FS/W) 2 Jul 29, 2012 12:16 PM
Sold Pair of balanced Wicked 4800 motor and matching ESC for twin EDF setup The Don Aircraft - Electric - Jets (FS/W) 4 Jun 25, 2012 07:34 PM
Discussion EDF fan balancing Mike873 Electric Ducted Fan Jet Talk 7 Apr 24, 2012 07:29 PM
Sold Exceed-RC stock 70mm EDF/Motor (balanced!!).......30 shipped RC_Bob Aircraft - Electric - Jets (FS/W) 2 Mar 26, 2012 11:46 AM