EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: ELS122 on October 20, 2022, 09:08:39 am
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how do I do this right? I have a transformer that has a mounting bracket to mount it on it's side, but I need to mount it on it's belly.
the most logical way to do this would be to drill holes trough the edges of the core, but how do I do this without shorting them all to each other, or does that not matter if it's just on 4 places?
I think the layers have all shorted anyway, the core is pretty loose, buzzes a ton, and the transformer heats up a lot even if no current is drawn from the secondaries.
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How about a picture? From a bracket on the side, you could use a right angle bracket(s) to mount it at 90°. There are probably other solutions that do not involve making new holes.
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Silicon steel is hard to drill. The shape is usually done by stamping.
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Transformer steel is very difficult to drill.
But with an very good drill bit this is possible and can be done.
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There is also the risk of deforming the slats, when the drill makes it through the first one and then pulls it up, and then the next one, etc.
Need to clamp it in very well.
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How about a picture? From a bracket on the side, you could use a right angle bracket(s) to mount it at 90°. There are probably other solutions that do not involve making new holes.
I don't want to use a 90° bracket because it's a big transformer (200VA at least), it would bend any bracket very easily.
Silicon steel is hard to drill. The shape is usually done by stamping.
well then I probably will just make some bracket to hold it that way.
here's a picture of the transformer, 1/4" TS jack for size reference: https://cdn.discordapp.com/attachments/774718507047977002/1032592721627586570/image0.jpg
mounting bracket removed so you can see the core
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It seems designed for mounting with a bracket(s) with laminations perpendicular to the mounting surface. Any edge can be made "down." I would use a pair of brackets -- one on each face of the laminations. If you want the coil facing the mounting surface, then I would use solid standoffs, e.g., bar or extrusion to fill the gap between the face of the laminations and mounting surface.
EDIT: This describes and provides images of various styles of mounting that I tried to describe:
https://www.mercurymagnetics.com/what-you-need-to-know-about-transformer-mounting-styles/ (https://www.mercurymagnetics.com/what-you-need-to-know-about-transformer-mounting-styles/)
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For a heavy transformer of the style shown, I'd go with clamping bars above and below parallel to and bearing on the outer limbs of the core, held together by four allthread studs through holes in their ends. The studs should not touch the core (or if they do, insulate them with rubber tubing) and the bars should be insulated from the core with rubber or foam sheet to damp vibration and avoid introducing any new eddy current paths. Probably the easiest would be to stick the bars to the core with 3M VHB tape or similar. The studs would protrude downwards through spacers to keep the bobbin from being crushed against the chassis and the whole assembly would be secured by nuts on the studs under the chassis.
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I chose to use the original bracket, and just weld a mounting plate at the top.
the bracket was crimped to the exact size of the core so unless I'd put a bolt trough the core to clamp it, it's probably my best option.
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Could you just 3d print or otherwise manufacture a closely fitting cage of non-conductive material to go around the transformer with mounting holes where you actually want them? Hold the transformer in to the cage by the fit of the cage around it, rather than by mounting holes through it? A chopepd up project box, perhaps one slightly too small on one axis so when you tighten down the box's lid with corner screws that tightly holds the transformer?
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It would bend any bracket??? Not so. The bracket just must be made of a sufficient gauge of steel or other material.
I also have a machine shop and can attest to the hardness of the alloys used for transformers. While it is not impossible to drill, I would want a solid carbide drill bit and would hold it in a milling vise in my milling machine to do that job. I guess it could be done with a drill press if you used a good vise and clamped it down to the table, but the milling machine would be my choice.
A local machine shop or junk yard may be a good source for a short length of heavy-duty steel or aluminum angle for a bracket. I am thinking about one of about 2" (50mm) or 3" (75mm) size. You should be able to cut it to length and drill holes in it with hand tools a lot easier than drilling holes in the transformer.
How about a picture? From a bracket on the side, you could use a right angle bracket(s) to mount it at 90°. There are probably other solutions that do not involve making new holes.
I don't want to use a 90° bracket because it's a big transformer (200VA at least), it would bend any bracket very easily.
Silicon steel is hard to drill. The shape is usually done by stamping.
well then I probably will just make some bracket to hold it that way.
here's a picture of the transformer, 1/4" TS jack for size reference: https://cdn.discordapp.com/attachments/774718507047977002/1032592721627586570/image0.jpg
mounting bracket removed so you can see the core
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It would bend any bracket??? Not so. The bracket just must be made of a sufficient gauge of steel or other material.
I also have a machine shop and can attest to the hardness of the alloys used for transformers. While it is not impossible to drill, I would want a solid carbide drill bit and would hold it in a milling vise in my milling machine to do that job. I guess it could be done with a drill press if you used a good vise and clamped it down to the table, but the milling machine would be my choice.
A local machine shop or junk yard may be a good source for a short length of heavy-duty steel or aluminum angle for a bracket. I am thinking about one of about 2" (50mm) or 3" (75mm) size. You should be able to cut it to length and drill holes in it with hand tools a lot easier than drilling holes in the transformer.
How about a picture? From a bracket on the side, you could use a right angle bracket(s) to mount it at 90°. There are probably other solutions that do not involve making new holes.
I don't want to use a 90° bracket because it's a big transformer (200VA at least), it would bend any bracket very easily.
Silicon steel is hard to drill. The shape is usually done by stamping.
well then I probably will just make some bracket to hold it that way.
here's a picture of the transformer, 1/4" TS jack for size reference: https://cdn.discordapp.com/attachments/774718507047977002/1032592721627586570/image0.jpg
mounting bracket removed so you can see the core
well yeah not literally any bracket, but I hardly find it practical to use half inch steel bars to mount a transformer, the thing weighs like 15 pounds so there could also be a risk of the bolts snapping so add higher quality, harder bolts to the list.
I used 2mm steel plate to make the brackets on both ends, and it's not going anywhere for sure.
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Bonjour
Most lams have prepunched holes for long screws to close the stack.
Drilling creates burrs that ruin the lam stack
EI/EE/UI standard laminations have clamps or brackets that grip the edges of the lam stack.
Jon
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You should not drill the laminated steel sheets. It creates a short circuit and excess heating.
Instead, you should mount the transformer using it's intended mounting holes. Using a custom made bent steel bracket if you have to.
Having a bracket custom made doesn't have to be very expensive. Draw some up in fusion360 and find a steel shop near you. Should be possible under 100 EUR. Or DIY with some mild steel.