Eject the core!
February 25, 2010 5:45 PM Subscribe
I'm looking to buy a silicon steel lamination core from a transformer. I frequently give presentations that discuss the design of these transformers and I'd like to have a sample to show the audience. Where can I buy this online?
I am only looking for the core itself, not an entire transformer. I would like a core like the one depicted in this image or this one. I've already checked eBay and only found solid ferrite cores; I'd really prefer one with laminations. Can anyone help me? Thanks.
I am only looking for the core itself, not an entire transformer. I would like a core like the one depicted in this image or this one. I've already checked eBay and only found solid ferrite cores; I'd really prefer one with laminations. Can anyone help me? Thanks.
Why don't you call the manufacturer? They'd probably love for you to pimp their designs and might just send you one for free.
posted by ged at 6:07 PM on February 25, 2010
posted by ged at 6:07 PM on February 25, 2010
Lots of transformers are vacuum-epoxy-infused (I forget the actual term), which makes them hum less, but probably makes them impossible to take apart. I think even after you hacksawed the windings off the laminations would still be stuck together.
I remember once having an educational electric-motor kit which involved stacking the laminations yourself and winding the windings. Maybe such things are still available?
You could buy laminations from, say, these guys (first supplier I found on google)?
posted by hattifattener at 7:57 PM on February 25, 2010
I remember once having an educational electric-motor kit which involved stacking the laminations yourself and winding the windings. Maybe such things are still available?
You could buy laminations from, say, these guys (first supplier I found on google)?
posted by hattifattener at 7:57 PM on February 25, 2010
Or hey, maybe these guys
All my usual parts sources just have ferrites and powdered iron.
posted by hattifattener at 8:05 PM on February 25, 2010
All my usual parts sources just have ferrites and powdered iron.
posted by hattifattener at 8:05 PM on February 25, 2010
Best answer: Most small power transformers can be disassembled. As a kid I took several of these apart with pliers, screwdriver, and an old knife. Vise-grips help too.
Here's a bunch:
http://www.allelectronics.com/make-a-store/category/790500/Transformers/Power-Xformers/1.html
Try this one for example:
http://www.allelectronics.com/make-a-store/item/TX-1814/18-VOLT-1.4-AMP-TRANSFORMER/1.html
To remove laminations, first remove the outer steel frame (the silver one with the mounting tabs) by using the screwdriver and pliers to bend the tiny tabs away from the bottom, then hammer the screwdriver down between the frame and core, and pliers to bend it outward. Get it loose and discard it. These are usually varnish-dipped, so you have to crack the varnish free.
Once you have the core/coils section separate you can work to loosen up the stack by removing two or more outer laminations. Look closely at the flat face of the core. You'll find a thin steel layer with an edge which sticks up, or perhaps a slot between two plates. Carefully jam an old knife under the edge to crack this outer lamination free from the varnish. Find other edges and do the same. Crack the entire outer lamination free all around the edge, bending it upward so it can be gripped with pliers (don't try to preserve its shape.) Pound the screwdriver down and around the whole lamination, and down through the part going through the coil spool, then yank back and forth with pliers. Your goal is to crack it entirely free from varnish, then remove and discard this outer lamination. Once complete, repeat the procedure on the other face of the core.
With two laminations gone, the core MIGHT be loose enough from the coil. If so, then you can slip a sharp knife between laminations to crack the varnish, then remove the next lamination unharmed. (If not, then don't bother preserving its shape, just hack and slash with pliers and screwdriver to get it out. If still tight, remove one or two more layers.)
At some point you'll be able to wiggle the coil/spool back and forth to crack the varnish free from the core. With enough room, you'll be able to slip a knife between the next lamination and crack it free, then do the next, and the next.
The outer laminations are usually "E" and "I" shaped, while the bulk of the inner ones are usually "C" and "T" shaped, oriented alternately so the narrow slots don't all overlap.
posted by billb at 12:43 AM on February 26, 2010
Here's a bunch:
http://www.allelectronics.com/make-a-store/category/790500/Transformers/Power-Xformers/1.html
Try this one for example:
http://www.allelectronics.com/make-a-store/item/TX-1814/18-VOLT-1.4-AMP-TRANSFORMER/1.html
To remove laminations, first remove the outer steel frame (the silver one with the mounting tabs) by using the screwdriver and pliers to bend the tiny tabs away from the bottom, then hammer the screwdriver down between the frame and core, and pliers to bend it outward. Get it loose and discard it. These are usually varnish-dipped, so you have to crack the varnish free.
Once you have the core/coils section separate you can work to loosen up the stack by removing two or more outer laminations. Look closely at the flat face of the core. You'll find a thin steel layer with an edge which sticks up, or perhaps a slot between two plates. Carefully jam an old knife under the edge to crack this outer lamination free from the varnish. Find other edges and do the same. Crack the entire outer lamination free all around the edge, bending it upward so it can be gripped with pliers (don't try to preserve its shape.) Pound the screwdriver down and around the whole lamination, and down through the part going through the coil spool, then yank back and forth with pliers. Your goal is to crack it entirely free from varnish, then remove and discard this outer lamination. Once complete, repeat the procedure on the other face of the core.
With two laminations gone, the core MIGHT be loose enough from the coil. If so, then you can slip a sharp knife between laminations to crack the varnish, then remove the next lamination unharmed. (If not, then don't bother preserving its shape, just hack and slash with pliers and screwdriver to get it out. If still tight, remove one or two more layers.)
At some point you'll be able to wiggle the coil/spool back and forth to crack the varnish free from the core. With enough room, you'll be able to slip a knife between the next lamination and crack it free, then do the next, and the next.
The outer laminations are usually "E" and "I" shaped, while the bulk of the inner ones are usually "C" and "T" shaped, oriented alternately so the narrow slots don't all overlap.
posted by billb at 12:43 AM on February 26, 2010
If you don't want to delaminate the core you could always just cut away the windings with a small hobby hacksaw or Dremel tool. A couple of well-placed slices ought to do.
posted by Rhomboid at 2:24 AM on February 26, 2010
posted by Rhomboid at 2:24 AM on February 26, 2010
Response by poster: Oh, sorry about the images. I guess they don't like hotlinking. Thank you all for the great suggestions though. It might be easiest to buy a transformer and take it apart, as several of you have suggested.
posted by Aanidaani at 2:40 PM on February 26, 2010
posted by Aanidaani at 2:40 PM on February 26, 2010
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Still, you could readily get what you want from many discarded electronic equipment chassis, by scavenging the power supply transformer, many of which still are made on stamped steel laminations, and then sawing the transformer in half, with a hack saw, and discarding any remnant winding/insulation materials. Perhaps a 30 minute investment of your time, once you have any discarded, medium power audio amplifier or receiver in your hand...
posted by paulsc at 6:05 PM on February 25, 2010