×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Remeber to bolt down your motors!

Remeber to bolt down your motors!

Remeber to bolt down your motors!

(OP)
I have been playing around with my little Casio EX-FC100. It is a decent little camera. Like most other 300 dollar cameras. But it has a feature that I will be using a lot when analysing problems with drives and loads. It can record at 410 frames/second. Even 1000 fps if you can accept a poorer resolution.
I filmed a DOL start of an induction motor. It jumped. I then reversed it. It jumps even higher and things on the table partake in the jumping.
It is interesting to see that it goes from 1000 RPM FWD to 1000 RPM BWD in less than half a revolution.

Go to http://www.gke.org/pub/ and select motor reversing.avi.

The file is quite large - around 9 MB. You have been warned.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Remeber to bolt down your motors!

Gunnar -- That's nothing! If you repeat the experiment with full vector control, you can flip the motor a full revolution! (Been there, done that...)

Curt Wilson
Delta Tau Data Systems

RE: Remeber to bolt down your motors!

(OP)
Yes. I believe you. I was more interested in the capabilities of the cheap little camera than tilting a motor.

It is interesting that the torque loop of a good vector control is so much better than the DOL. The explanation is, of course, that a good vector control takes care of the internal voltage drop (in Rs and Ls) so that the air gap voltage is delivered with no influence from stator parameters. Hmm.. now, where did I put that NFO drive?..

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Remeber to bolt down your motors!

Near video.  That is suprising to have that capability in a relatively cheap camera.

 I can only think of one problem where we wanted high speed camera.  Breaker was tripping for unknown reason upon starting.  One of many postulated causes was abnormal vibration of the contactor influencing the breaker.   Seems like 1000 fps would be fast enough to evaluate that (especially if comparing to a sister)

What other sort of problems might this be useful for troubleshooting?
 

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

RE: Remeber to bolt down your motors!

Pretty interesting Gunnar!  I wish my $2,200 camera took movies of any kind!

Keith Cress
kcress - http://www.flaminsystems.com

RE: Remeber to bolt down your motors!

One other possible thing that strikes me is this might be an alternative to a strobe light that we use for looking at rotating equipment and especially belts.   Can the camera play back the video in slow-motion immediately after recording, or do you have to take it back to a computer to do that?

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

RE: Remeber to bolt down your motors!

(OP)
Can view directly in the camera. Possible to zoom while viewing. Also possible to edit and change viewing speed in camera. I have a problem with a friction welder for shafts that I will test this camera on. Rotates shafts against each other for ten seconds, then ramps down in 300 milliseconds so that weld solidifies. Something happens during ramping down. Hope to see what is happening using this camera.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Remeber to bolt down your motors!

Wish I had that video 20 years ago. I was trying to convince a plant engineer that he needed to put soft starters on some small vibrating screen motors. The inertia of that eccentric weight was causing the initial torque to be expressed into the motor mounting bolts. He kept saying "They're just little 10HP motors, no big deal. I'm not spending budget money on some fancy starter." But 6 months later he had to replace the concrete pilars that they were mounted on because they broke out the mounting bolts.

We recorded some ground fault tests in MV switchgear at 2k FPS once, it was like watching performance art.


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln  
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies  

RE: Remeber to bolt down your motors!

Pete -- Your mention of strobe lights reminded me that we used to use the 120 Hz flicker of fluorescent lights as a strobe to check the speed-lock capabilities of our vector controllers.

I still remember the morning after we switched to electronic ballasts for our fluorescent lighting in the mid 90s -- our top programmer was in a near panic because he thought he couldn't lock in on speed any more.

Curt Wilson
Delta Tau Data Systems

RE: Remeber to bolt down your motors!

That's a nice link there Mike.  The EE tests the camera on a motor - the computer geek tests it on cheerleaders - go figure.   

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

RE: Remeber to bolt down your motors!

"The EE tests the camera on a motor - the computer geek tests it on cheerleaders - go figure."

Reminds me of the classic engineer joke with the bicycle and the naked girl.


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln  
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies  

RE: Remeber to bolt down your motors!

(OP)
Jeff, I would have chosen the bicycle, too.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Remeber to bolt down your motors!

(OP)
Jeff!
I sacrificed a perfect can of beer for you - and for science. Go to http://www.gke.org/pub/ and download the exploding beer can. Not Cheer-leaders, but you can't have it all  sad

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Remeber to bolt down your motors!

You've talked me into it.  Now all I have to do is convince one of my bosses (home or work) that it's a good investment.

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

RE: Remeber to bolt down your motors!

.... but I don't think I'll show my wife the cheerleader video!

By the way here are some reviews:
http://www.amazon.com/Casio-High-Speed-EX-FC100-Stabilized-Black/product-reviews/B001OTZR22/ref=cm_cr_dp_all_helpful?ie=UTF8&coliid=&showViewpoints=1&colid=&sortBy=bySubmissionDateDescending

As expected it is not perfect.  Big complaint seemed to be focusing.  Also it needs a lot of light (what else do you expect for rapid shooting = short exposure time).   It may not be a great all-around camera but certainly looks great for high-speed shooting.

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources