0

Help Identify this capacitor
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Help Identify this capacitor

by tge1986 on Thu Mar 19, 2009 2:42 pm

Hi, I'm trying to find a replacement part for this capacitor, it's used to drive a 3 phase motor for a color processing machine for c-prints. Here is a link to the image of the capacitor on flickr.
http://farm4.static.flickr.com/3424/3368670312_2e893f8eab.jpg?v=0

If anyone can help identify this and know of a place to order a replacement, digi-key? mouser?

Thanks for the help.
tge1986
 
Posts: 28
Joined: Mon Jul 21, 2008 10:09 pm

Re: Help Identify this capacitor

by zener on Fri Mar 20, 2009 9:06 pm

Wow. That is an interesting one. Are you sure it is bad? It looks pretty rugged... I have never seen a cap with a stud on the end. You could get a film cap with similar ratings but it wouldn't have the stud like that. Otherwise you would have to get the exact thing. I do not recognize that mfg.

zener
 
Posts: 4429
Joined: Sat Feb 21, 2009 2:38 am

Re: Help Identify this capacitor

by Amberwolf on Sat Mar 21, 2009 12:16 am

My first question would be "is it the capacitor that's bad?", but assuming you've already troubleshot down to that:

Mouser has always been helpful to me in identifying parts, even if all I have is a photo. You could email it to them and they can see if they have one like it, or try their online chat help line with a tech.

Digikey can probably also do the same thing.

FWIW, there is a similar capacitor (including stud) on my electric lawnmower, and I have had to add a nut to the bottom of the stud to hold it on, as the plastic it screws into is too loose for all the vibration it gets and it falls out. :)

Of course, your best guarantee of getting the right part is to contact the manufacturer of the machine to see if they sell one, or if they have a parts list you can get to at least ensure you have the right part (assuming the parts are numbered with something other than just their own internal company designations).
Watch me build an electric bike from assorted junk!
Alternative Energy Sources for the Home from Recycled Junk
A subsidiary of Cybernetic Necromancers, Discorporated:
"We Bring Dead Things To Life"
Amberwolf
 
Posts: 310
Joined: Wed Oct 08, 2008 2:42 am
Location: Phoenix, AZ, USA

Re: Help Identify this capacitor

by zener on Sat Mar 21, 2009 1:36 am

I think this is a good cross. But check the datasheet before you buy it.

http://www.newark.com/jsp/search/produc ... 1721829242

Please note it is the part at the top of the page with no photo, not the "substitute" part shown at the bottom of the page with the photo. The datasheet SHOULD have the correct drawing, however when I clicked on it it brought up a drawing of a FAN!! Gotta love Newark.

Here is the correct datasheet: http://www.farnell.com/datasheets/24524.pdf

These have 2 wires coming out the end and the stud is plastic (I think). I cannot tell from your photo if that stud is one of the cap connections, since I cannot see the end of the wire in your photo.

zener
 
Posts: 4429
Joined: Sat Feb 21, 2009 2:38 am

Re: Help Identify this capacitor

by tge1986 on Sat Mar 21, 2009 10:39 pm

The capacitor is NOT bad, it's fine, it was the motor that was bad, however we were told by the manufacturer of the machine that we should change the capacitor when we change the motor and even wear and tear sort of thing i'm guessing, It's a $800 motor on a $80,000 c-printer we thought we would take the manufacturers recommendation, however they didn't give us any info on were to get a replacement cap or even the specs. Thanks for the help everyone.
tge1986
 
Posts: 28
Joined: Mon Jul 21, 2008 10:09 pm

Re: Help Identify this capacitor

by Amberwolf on Sun Mar 22, 2009 3:08 am

I suppose the recommendation makes some sense, depending on what caused the motor failure.

What's going to happen to the old motor? (I'm always looking for different kinds of motors, even defective ones, to try out on my various recycled-parts e-bike projects)
Watch me build an electric bike from assorted junk!
Alternative Energy Sources for the Home from Recycled Junk
A subsidiary of Cybernetic Necromancers, Discorporated:
"We Bring Dead Things To Life"
Amberwolf
 
Posts: 310
Joined: Wed Oct 08, 2008 2:42 am
Location: Phoenix, AZ, USA

Re: Help Identify this capacitor

by tge1986 on Sun Mar 22, 2009 12:29 pm

We are going to try to get the motor rebuilt, so we can have a spare on hand just in case. The cost of the replacement was great enough to justify spending the money to get it rebuilt, even if we never need it, the first one lasted 16years so it may be sitting on the shelf collecting dust for a long time, but It's good to know that we have a spare...just in case.
tge1986
 
Posts: 28
Joined: Mon Jul 21, 2008 10:09 pm

Re: Help Identify this capacitor

by Amberwolf on Sun Mar 22, 2009 2:46 pm

Good idea. What was wrong with the motor? A coil, or a bearing, or a sensor?

If a bearing, that is easy to fix, if you have the right bearing puller, depending on how it is mounted in the case, assuming it's a standard sealed-bearing type common in motors.

Rewinding coils, on the other hand, is commonly a heckuva task. :( No fun at all, since often one must unwind the WHOLE motor first, and then rewind it all again with new wire, because of overlapping coil sets. With BLDC motors it's often not that onerous.

If it's just a bad Hall sensor, then typically it's super-easy to fix, as long as you can find the same part or a functionally-identical one.
Watch me build an electric bike from assorted junk!
Alternative Energy Sources for the Home from Recycled Junk
A subsidiary of Cybernetic Necromancers, Discorporated:
"We Bring Dead Things To Life"
Amberwolf
 
Posts: 310
Joined: Wed Oct 08, 2008 2:42 am
Location: Phoenix, AZ, USA

Re: Help Identify this capacitor

by tge1986 on Sun Mar 22, 2009 8:13 pm

We aren't really sure what the issue is, it was dusty and dirty as hell when we pulled it out, and it didn't spin very freely, it felt like it got caught or something at a certain part on each revolution, maybe the bearings but i'm not sure. All I know is that the new motor works great the machine is working again.
tge1986
 
Posts: 28
Joined: Mon Jul 21, 2008 10:09 pm

Re: Help Identify this capacitor

by Amberwolf on Sun Mar 22, 2009 11:36 pm

If it feels as if it is catching at certain points that are all at the same portion of a circle away from each other, that's a normal part of a high-power-magnet DC motor, called "cogging", and is caused by the magnets pulling on the iron core in certain places, as it aligns during rotation with them. It's one thing that causes lower efficiency in high-torque motors, but has ways to be compensated for (such as angling the magnets so they "overlap").

If it only feels this way at a single point, it's possible one of the hall sensors came loose and it or it's remains are physically grinding against the rotating portion of the motor.

It can also be just a bearing, where a piece of metal from a bearing or housing is grinding underneath one or more of the bearings. Happens to many things with high-torque loads on them, especially off-axis ones, like bicycle pedal-crankshaft bearings.
Watch me build an electric bike from assorted junk!
Alternative Energy Sources for the Home from Recycled Junk
A subsidiary of Cybernetic Necromancers, Discorporated:
"We Bring Dead Things To Life"
Amberwolf
 
Posts: 310
Joined: Wed Oct 08, 2008 2:42 am
Location: Phoenix, AZ, USA

Please be positive and constructive with your questions and comments.