PC Board for Amveco PC mount low profile toroidial transformers

[sbelyo]

Does anyone have or know where I can find a board that would let me mount a single or side by side Amveco PC mount low profile toroidial transformers?  I'm just looking for a board that would have AC in and out going to terminal blocks and allow the use of standoffs.

Amveco PC mount low profile 50VA toroidial transformers https://talema.com/wp-content/uploads/datasheets/70000K-72400K.pdf

 

If not, I'd gladly pay someone for their time to lay out a board for me.  Something like the pic in here

 

Edited October 11, 2020 by sbelyo

[johnwmclean]

The ones on eBay are only suitable for 15/25VA sizes.

https://www.ebay.com.au/itm/Bare-PCB-mounting-PCB-install-circuit-board-for-Talema-seal-transformer-Square/132276238616?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Would be pretty simple to breadboard, ensuring you use stand-offs and insulate the underside.

[sbelyo]

that's just what I was looking for...  The 50VA is just slightly bigger unfortunately.  I did order some protoboard so that's most likely what I'll use

[jamesmking]

6 hours ago, sbelyo said:

that's just what I was looking for...  The 50VA is just slightly bigger unfortunately.  I did order some protoboard so that's most likely what I'll use

I can make gerbers for you - no cost for something simple. If you can post the measurements, hole spacing, track layout etc. PREFERABLY in mm not inches.

[sbelyo]

sure, let me get cracking.

[sbelyo]

Ok, excuse my crude drawing but this is my idea for a basic dual side by side layout.  The AC in and out would just be the normal terminal block we all use. 5.08mm pitch with a 1.3 mm hole.  I use 4-40 stand offs so the holes would be 3.26 mm or there abouts.  Not sure what size hole is usually standard for that.

For the transformer pin spacing and hole size I circled the 25, 35, and 50 VA models, the specs are in the chart.  I was looking to do those three.  Let me know what you think.

[jamesmking]

The m4/m5 screw hole looks centred in the diagram left to right but not top to bottom...  looks like its displaced 2mm bellow centre on the transformer? Slightly larger holes for the transformers and slightly smaller for the 25VA. AC carrying tracks moved further apart. ALL tracks made slightly wider.

added transformer windings onto silkscreen. moved mounting holes now centred

 

 

 

This zip v1.4.zipcontains the gerber files. The zip needs checking for hole sizes, hole placement etc. Note some isolations slots are 0.5mm. NOTE THIS HAS NOT YET BEEN CHECKED AND VERIFIED.. This needs careful checking to verify pad placement, m4/5 hole placement etc.

All tracks are on the underside of the board.

 

Edited December 15, 2020 by jamesmking

[sbelyo]

I wasn't sure how to draw the traces.  I figure leave the primary and secondary alone so anyone and choose 115 or 230 on the primary and parallel or series on the output

[sbelyo]

1 hour ago, jamesmking said:

ok working on it.  I have done the 25va transformer (I think. I assume you would like the 35 and 50va on the same pcb if possible.

yep that's right.  If you have to drop one to make it fir you can cut out the 35.  I really only need the 25 and 50VA

[sbelyo]

This look really good!  I should have some 50VA coming next week.  I don't have any 25VA, let me see if one is in stock

[Pars]

Maybe just put a voltage select switch right on the board as well, and only have 2 AC in (L/N)?

EDIT: Also note that the 35VA/50VA trans use 1.3 mm pins, larger than the others.

Edited October 12, 2020 by Pars

[sbelyo]

3 minutes ago, Pars said:

Maybe just put a voltage select switch right on the board as well, and only have 2 AC in (L/N)?

EDIT: Also note that the 35VA/50VA trans use 1.3 mm pins, larger than the others.

That would be cool...  It looks like the outer holes are bigger so I think that's ok.

[spritzer]

The mains traces are pretty close together and close to the output on the bottom so you might run into issues with that.  I would at minimum move them to the other side of the board and add slots to further isolate them. 

[jamesmking]

4 hours ago, spritzer said:

The mains traces are pretty close together and close to the output on the bottom so you might run into issues with that.  I would at minimum move them to the other side of the board and add slots to further isolate them. 

Thank you for the feedback Spritzer, yep I am concerned about that. I'm still working on the track routing.... first priority was getting right the pad placement. v1.3 now has isolation slots and the ac lines rerouted further from the secondary output pins.... I also decreased the ac track width from 1.5mm to 1mm just in the area around the transformer solder pads to give a bit more clearance. The transformers have been moved a bit more apart to increase primary to secondary spacing there too. I have also moved the secondary tracks further from the m5 screw hole. All the tracks are on the underside of the board, I could move the secondaries to the top side as long as the transformers are not going to short to them.

Edited October 12, 2020 by jamesmking

[sbelyo]

looks good.  I expect the transformers next week so I'll measure that to check.  Unless someone here has one

[Pars]

The voltage selector switches I normally see used are C&K, mouser pn 611-V80212MS02Q. Other flavors available; this one is the straight PC mount version.

Edited October 12, 2020 by Pars

[sbelyo]

That switch is cool, I like that

[n_maher]

If adding features to the board might I suggest a fuse?  Not sure if this is a one-off and not worth bothering, but sometimes a chassis just doesn't lend itself to the somewhat monstrous integrated IECs that have both voltage switching and fuse provisions.  That's what made me think of it anyway. 

[kevin gilmore]

if you rotate the left transformer 180 degrees, makes the high voltage wires a lot shorter.

[sbelyo]

9 hours ago, n_maher said:

If adding features to the board might I suggest a fuse?  Not sure if this is a one-off and not worth bothering, but sometimes a chassis just doesn't lend itself to the somewhat monstrous integrated IECs that have both voltage switching and fuse provisions.  That's what made me think of it anyway. 

For me it'd be cool to do the voltage switch.  I have enough room for an IEC inlet with a fuse.  Let me measure to see how long the board can be

 

7 hours ago, kevin gilmore said:

if you rotate the left transformer 180 degrees, makes the high voltage wires a lot shorter.

My only thinking was to have AC in on the left so the wires are very short to the front panel switch and then the secondaries are facing the AC in on the PSU boards.  Basically just keeping the wiring as short and neat as possible.  Is that creating more of a problem with noise the way it is?

[sbelyo]

Max for length is 228.5 mm

 

[sbelyo]

transformers should be here tomorrow

[sbelyo]

At first glance and a quick measurement from the bottom, the hole seems to be dead center.  I will print out the outlines this weekend and see where it matches up

Edited October 20, 2020 by sbelyo

[sbelyo]

Can anyone recommend a free gerber viewer that lets you print the layers true to size? Or at lease view them on screen where they're accurate enough for measurement.

Edited October 25, 2020 by sbelyo

[luvdunhill]

9 hours ago, sbelyo said:

Can anyone recommend a free gerber viewer that lets you print the layers true to size? Or at lease view them on screen where they're accurate enough for measurement.

PentaLogix ViewMate should work