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Thread: Dynamic Balancer DIY?
09-06-2009, 10:18 PM #1
Dynamic Balancer DIY?
I was wondering if there is a cheap software program that can be used on a laptop with accelerometers and strobes to balance wheels or pulleys. I don't know a thing about dynamically balancing except I saw a demonstration once of balancing a large pulley.
09-06-2009, 10:37 PM #2
Funny thing. This popped up on my first stab on Google:
The next hurdle is the sensors and their interface with the computor. Maybe there's a USB analog to digital gizmo.
09-07-2009, 01:15 AM #3
The sensors I have seen used are simple piezoelectric biomorphs (used as buzzers) attached to a compliant support for the part being balanced. No need for a computer, just amplify the signal and feed it to a comparator with adjustable trip point, use the comparator to drive a led or laser which illuminates the part.
The biomorphs are AC response so they only register the imbalance.
A computer could be used, accelerometers crop up on ebay and the like in the US at least and these would work also many commercial balancers just put 2 single axis accelerometers on pads fixed to the machine at 90 degrees along the axis of rotation..
09-07-2009, 04:19 AM #4
I can see the reason for the computer. It's not just the magnitude and orientation of the unbalance that gets tricky. Determining the mass, radius, and axial placement of the correction in relation to the bearings is where a computer can be invaluable. Saves all that drilling here and there hoping for a miracle.
I can make a Yakimoff balance out of old car parts and dial indicators and find the unbalance of rotating parts with trial weights and acres of graph paper - I think I can after 40 years since my last solo shot at it. I vote for a computer function that tells me where to correct.
09-07-2009, 04:33 AM #5
the guys who built jet engines for models planes are the right ones to ask for advice here. A little work with google will surely yield results, I remember reading about balancing engine parts that run at 60.000rpm with a homemade mock up with good results.
09-07-2009, 06:16 AM #6
I've never done it myself, but have looked into. Seems to me there was a big discussion about it on this site. Here's s/w that you can use to measure the signals, but it doesn't do the balance calculations:
I hear that you can use a loudspeaker with a weight glued to the cone as a transducer. Here's all you ever wanted to know about dynamic balancing:
09-07-2009, 06:20 AM #7
Yes, calculating where the weight goes is the tricky part. Especially on more than one plane.
09-07-2009, 02:53 PM #8
That was probably the Excel spread sheet that Conrad Hoffman wrote. That does all the calculations. The link is in the first post of this thread.
If you down load it, make sure to click on the second page tab of the Excell doc to see the calculation page.
09-07-2009, 03:23 PM #9
We were talking about that in another thread. I was quite interested in Andy Paul's solution at http://usbmicrobalance.com/index.html . I already had the acquisition boards and accelerometers and did do some balancing but it was not efficient since the I was guessing about the corrections.
To save time I purchased his system which I found to be reasonably priced (everything is on his web site). Some people are even balancing turbo chargers with this. I have been delayed a bit by our bearing package therefore I have only done a bit of field balancing with it.
You mention using a strobe - well he does much better than that with his laser sensor.
09-07-2009, 03:32 PM #10
I bought these three items from a flight department that was closing down a year or so ago, for $1000.00. Heck of a deal.
Half of the value was in the plotter. I've seen the basic balance/strobe kits go for $300.00 on ebay.