[carlos spud]

i have to fit 5 of these in one chassis so they need to be small also does any one know if you can stack or mount the transformers on their side?TIA
Carlos

[JoshK]

Carlos, the transformers that I listed in the first post of the UcD construction thread are a good cheap example of such a tranny.  I am selling two as you know and you can order direct from Dan also.

[Gordy]

Hi Carlos,

DVV/Dijan has written 2 excellent articles on power supplies at his site Zero Distortion... http://www.zero-distortion.com/start.htm . The first one, Universal Power Supply has several pics of transformers mounted with L type brackets and the second, Designing Your Own Powers Supplies is a classic and a must read!  Many other good essays there as well, Enjoy...

[Occam]

You can stack toroids with any orientation you wish. But you cannot mount them with a complet electrical connection through the center completing a 'circuit' that continues around from the outside through the inside. This will cause a 'shorted turn' on the transformer(s), and can cause a meltdown, literally. In other words, you can stack a whole buncha toroids on top of each other and secure them with a metalic bolt through the center. But if, in addition, you secure that bolt at the top with a metal bracket which connects to the chassis which is also securing the bolt at the bottom, you will have that 'shorted turn' and those resultant problems.

[carlos spud]

This forum truly is a great resource! thank you all for the replies and reading material
Cheers, Carlos

[andyr]

You can stack toroids with any orientation you wish. ... In other words, you can stack a whole buncha toroids on top of each other and secure them with a metalic bolt through the center. ...

Hi Paul,

I thought that it was essential NOT to put power transformers (toroids or otherwise) in close proximity, as the closer they are the more their magnetic fields will couple?  If you are using toroids then putting one on its side next to one which is secured horizontally (ie. "conventionally") is better than simply mounting both horizontally.

If you're using EI transformers then adjacent ones should be oriented at 90 deg to each other.

Regards,

Andy

[Occam]

Andy,

Think back to you first physics course in electricity and magnetism, and dredge up memories of the 'right hand rule'. The magnetic flux in a toroid is largely contained within the torus, with minimal fringing. This, and economics, is largely the reason many prefer toroidal transformers when mounted within a component.

Actually, do a google search on 'right hand rule' and 'torus' and you'll find examples from about every introductory E & M course.

Stacking toroids is very common on large amps, and as long as their is no 'shorted turn', no problemo. Far fewer problems with induced hum or interacting transformers than with other types of transformers.

If you've a mind to, take a toroid and power it while under a small load. Put a large sheet of paper on top of it. Sprinkle iron filings on top of the paper.  Try the same with a EI core transformer.

Ever pedantic,
Paul

[andyr]

Andy,

Think back to you first physics course in electricity and magnetism, and dredge up memories of the 'right hand rule'. The magnetic flux in a toroid is largely contained within the torus, with minimal fringing. This, and economics, is largely the reason many prefer toroidal transformers when mounted within a component.

Actually, do a google search on 'right hand rule' and 'torus' and you'll find examples from about every introductory E & M course.

Stacking toroids is very common on large amps, ...

Thanks, teach!

Yes, I do seem to remember the good feature of toroids was that they contained the magnetic flux well.

However, one of the "rules" that I was taught, for speaker crossovers, was to make sure the inductors are a) as far away from each other as possible and b) placed at right angles, if possible.  Otherwise their magnetic fields will couple.

I thought an inductor was similar to a toroid ... are U saying they are in fact completely different beasts?

Regards,

Andy (your eager-to-learn student!)

[Occam]

Andy,

A toroid is one of the many geometric shapes of magnetically permeable materials upon which one can wind an inductive component, inductor, transformer, cmc, etc....

Lets consider an inductive component wound upon 2 differents shapes on the same permeable material, an electromagnet. Lets say that material is very soft iron. The first shape is a torus, a donut, upon which we put a single winding.  Put a dc current trough it and you'll find it really can't pick up very much ferrous material as the magnetic flux lines are largely contained  the within the torus itself.  Now lets cut the torus between that small gap between where the winding begin and end, and straighten that donut into a rod. Now we have a very effective electromagnet, which can pick up substantially larger amounts of ferrous material as the magnetic flux is very strong at both ends of the rod.

Simply put, a toroid is the magnetic equivalent of that universal mythic creature, a snake devouring its tail.......

[andyr]

Andy,

A toroid is one of the many geometric shapes of magnetically permeable materials upon which one can wind an inductive component, inductor, transformer, cmc, etc....

Simply put, a toroid is the magnetic equivalent of that universal mythic creature, a snake devouring its tail. ...

Sure, Paul,

But a coil (as used in a speaker crossover) is a long length of wire - or a long length of ribbon - wound in circles to form a torus.

But are U saying that, because there is no permeable "core", the magnetic field of an inductor indeed extends well beyond the 'donut' of wire/ribbon and hence must be kept more separate from another inductor than is the case with a toroid transformer?  

Regards,

Andy

[Occam]

But a coil (as used in a speaker crossover) is a long length of wire - or a long length of ribbon - wound in circles to form a torus.

You 'can' call it a torus, I call it a rod (if the rod is air, so much the worse for stray magnetic fields) Again, I'll ask you to remember the "right hand rule".  The 'shape' refers to the circuit that the magnetic circuit takes, the core, not the windings.
This really is a situation where you need to check a textbook out from the library. Rictures really are worth a thousand words.