[IN STOCK] L-1 Power System.

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L-1
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Post by L-1 » Sat Dec 27, 2014 1:06 pm

I've read in medical electric equipment standards, air distances 250V for user safety is 2mm.
This is 2mm square I drew in the center.

Image

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Post by L-1 » Sat Dec 27, 2014 7:27 pm

I've unwound several winds from 15V 50VA transformer which gave 16.5V on free running. Made it 15V on free run or 13.5V under load.

Now under dual 10 Ohm load or 1.2A at the out, heatsinks are stable at 63-65°C. I tested during one hour, the temperature was stable. It's 20°C less than was with 15V trans. and about half what regulators can hold (125°C).
Last edited by L-1 on Sun Dec 28, 2014 1:19 pm, edited 1 time in total.

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Post by L-1 » Sat Dec 27, 2014 8:10 pm

Nantonos wrote: Ribbon cable seems a poor choice for bus to PSU connection (but I see you also offer a screw terminal option). I would have preferred to see multiple spade/faston connections for the +12V, 0V, and -12V outputs. Otherwise people are tempted to daisy-chain from one busboard to another. The 0V return needs to be low impedance.
I made pads for spades.
Now spades, MTA-156, PTR-500, PTR-300, ribbons are possible. The same as on my busboards.
Last edited by L-1 on Sun Dec 28, 2014 12:49 pm, edited 1 time in total.

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Post by slow_riot » Sat Dec 27, 2014 10:43 pm

230VAC is enough to stop a human heart, it should not be exposed anywhere. Those screw terminals are a disaster waiting to happen.

What system in is place to establish a proper system ground with provision for earth for safety and RFI screening?

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Post by L-1 » Sun Dec 28, 2014 6:32 am

OK
I made the board a bit longer, now 180mm, and rerouted for MTA-156 connectors. They have:
Voltage Rating—600 vac
Current Rating—12.5 amp max. on a single circuit.

Image


230 - 115V jumpers will look so:

230V:

Image


115V:

Image

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L-1
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Post by L-1 » Sun Dec 28, 2014 12:41 pm

I've tested with 50VA 13.5V transformer at dual 8 Ohm load, it's 2 x 1.5A at the out.
This is near maximum value 1.65A at the out which this transformer can give.
PSU worked good but transformer started to produce ripples after 30-40 minutes.
Heatsinks was 57°C, it's colder than was with 10 Ohm load because of bigger dropout at the transformer.
The hottest parts were transformer 65°C and diodes 80°C.

I hope 60VA transformer will hold this load without ripples.
For 50VA I would recommend not more as 2 x 1.3A at the out.


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Post by mechie » Mon Dec 29, 2014 8:40 am

I look forward to this kit, I think I have uses for a couple of these, the mains termination doesn't bother me at all, it's my day job.
BUT...
I do think there could be issues with this for some with less experience:-
Image
The copper tracks could easily be covered with a square of fibreglass under the transformer, easy and cheap - even a bit of CD case would suffice.
Image
This voltage selector worries me - if the mains is turned on with this selector unplugged there will be bare pins at mains voltage.
I wonder how many will ever need to swap from 110v to 240v so often that this is worth the effort? maybe just simple solder pads for the transformer tails to be soldered to would suffice, set at construction time and probably never seen again?
Sorry, just not a big fan of mains connectors that aren't required :hide:

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Post by L-1 » Mon Dec 29, 2014 10:12 am

mechie wrote:I look forward to this kit, I think I have uses for a couple of these, the mains termination doesn't bother me at all, it's my day job.
BUT...
I do think there could be issues with this for some with less experience:-
Image
The copper tracks could easily be covered with a square of fibreglass under the transformer, easy and cheap - even a bit of CD case would suffice.
Image
This voltage selector worries me - if the mains is turned on with this selector unplugged there will be bare pins at mains voltage.
I wonder how many will ever need to swap from 110v to 240v so often that this is worth the effort? maybe just simple solder pads for the transformer tails to be soldered to would suffice, set at construction time and probably never seen again?
Sorry, just not a big fan of mains connectors that aren't required :hide:

This is a prototype which I made on DIY board.
Final boards will be factory made and look like this:

Image

No need to unplug this selector under voltage.

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mechie
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Post by mechie » Mon Dec 29, 2014 11:33 am

L-1 wrote: No need to unplug this selector under voltage.
I agree - but COULD it be done?

I am told that, as a toddler, I pushed a knitting needle into a 240v mains socket and then sucked the end :deadbanana: I now have frizzy hair.
COULD it be done?

I have a couple of your PCBs - excellent stuff, if a cover PCB like that for the vocoder set were made to hide the mains copper tracks I think it would be much safer for the masses.

As I said, I feel confident with my construction skills but some may be on their first build with this.

ps. struggling with slow connection today - keep losing Muff's site connection :cry:

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Post by L-1 » Mon Dec 29, 2014 12:14 pm

If you look at PCB picture you will see three MTA-156 headers at the left.
The bottom one - input from main voltage.
The top one - to transformer.
The middle one - for jumpers 115-230V which will be done so:

Image

Output from transformers secondaries - at right of transformer.


Yes, boards will be as usually from me 2mm black/gold. Like for the Vocoder, even better.

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latigid on
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Post by latigid on » Mon Dec 29, 2014 12:24 pm

Presumably the boards will also have a stop mask, meaning the only exposed mains will be on solder points. Short of surface mount connectors or buried traces there's a limit as to how intrinsically safe a self assembled PCB can be.

Another option is to directly connect the primary winding to the mains switch/ power connector. That way all joints can be made with insulated plugs.

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Post by rosch » Wed Dec 31, 2014 2:34 pm

Usually you don't solder stranded wire with mains. Best way would be spade connectors on the board and female insulated plugs, so IF a cable goes off it cannot make contact to anything. Also good if there is a way to fix the cable to the board (with a cable tie through a hole for example) so they cannot move even if the trafo burns out.
Idk, trafo on board isn't my taste too but that's probably just taste.

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Post by L-1 » Wed Dec 31, 2014 6:04 pm

I've already made new prototype with completely isolated main voltage. Only need to make photos. Will show tomorrow. :tu:

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mechie
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Post by mechie » Thu Jan 22, 2015 5:37 am

L-1 wrote:I've already made new prototype with completely isolated main voltage. Only need to make photos. Will show tomorrow. :tu:
OK, so the forum is back from an unexpected holiday...
Is it time to "show and tell" yet? I'm keen to see this come to life :hyper:

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Post by Cat-A-Tonic » Thu Jan 22, 2015 8:53 pm

Can we order full kits for the 15V version?

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Post by J3RK » Fri Jan 23, 2015 4:11 pm

I recommend using these power inlets for my PSU. They handle the 240/120 switching internally. You open the fuse drawer, flip it over, and you're done. Nothing on the PSU board itself. You can get filtered and non-filtered types.

http://www.digikey.com/product-search/e ... =PS0SXDS60
Are you lemon? Does your head come to a nub?

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Post by spacedog » Fri Jan 23, 2015 4:35 pm

I am interested in the "Only PSU kit".

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Post by mechie » Sat Jan 24, 2015 11:28 am

J3RK wrote:I recommend using these power inlets for my PSU. They handle the 240/120 switching internally. You open the fuse drawer, flip it over, and you're done. Nothing on the PSU board itself. You can get filtered and non-filtered types.

http://www.digikey.com/product-search/e ... =PS0SXDS60
Looks like an easy optional 'upgrade' for this project - personally I will still be building for a fixed voltage.

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Post by spacedog » Thu Feb 12, 2015 8:16 am

Is this project still alive?
On 30 January 2015 at 01:32 i tried to order:

Only PSU kit. Everything which needed to build as pictured include transformer.
Prepay in January price - $68 + $20 shipping.


...but no reply. :waah:

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Post by L-1 » Fri Feb 13, 2015 8:31 am

spacedog wrote:Is this project still alive?
On 30 January 2015 at 01:32 i tried to order:

Only PSU kit. Everything which needed to build as pictured include transformer.
Prepay in January price - $68 + $20 shipping.


...but no reply. :waah:

Were not enough orders to make it real.
I will collect my own money to buy everything. No pre-pay discounts in this case.
Will promise nothing about time and dates. Will see.

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Post by spacedog » Fri Feb 13, 2015 10:02 am

Good luck!

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Post by mechie » Sun Feb 15, 2015 9:16 am

L-1 wrote:Were not enough orders to make it real.
This is a great shame, a chance to get a rock-steady PSU with a good current capability and so little interest :hmm:

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Post by Nantonos » Tue Feb 17, 2015 6:28 am

I see post 2 was updated with new prices.

Is the spade output option still available?
ondes | current rack
I am afraid a firmware change will not be able to turn a rather expensive 16-bit DAC into a 16-bit ADC, and flip all those op-amps :)

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Post by L-1 » Tue Feb 17, 2015 7:16 am

Nantonos wrote:I see post 2 was updated with new prices.

Is the spade output option still available?

The prices are the same, I just removed pre-pay discounts.

Yes. Spades are possible.

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Post by mechie » Thu Feb 19, 2015 5:36 am

L-1 wrote:The prices are the same, I just removed pre-pay discounts.
Still hoping this happens, I requested two PSU only kits via the link earlier in this project thread, I just want to confirm I'm still in for two kits :hyper:

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