[sdiy] Hooking up a Power-One unit

[Roy J. Tellason]

On Sunday 05 April 2009 07:33:08 pm David G. Dixon wrote:
> John,
>
> The terminals are little solid cylinders, about 1 cm high and maybe 2.5 cm
> in diameter, 

Was that supposed to be 2.5mm?

> with one little ring or flange about halfway up and another at the top. 

That sounds like what I'd call "turret" terminals.  I have some boards 
somewhere that have a row of those down each side,  with the equipment 
originally having parts connected across the board and a wiring harness 
running along either side to make the rest of the connections.  Crude,  but 
this was pretty old stuff.

> They look like something is supposed to slide over them, but I 
> don't know what.  

You just wrap some solid wire a turn or two around 'em and solder.

> Also, there are seven of them, labelled as follows: 
>
> -OUT   -S   +S   COM   -S   +S   +OUT
>             -------------
>
> I'm presuming that one uses the -OUT, +OUT, and COM terminals, and the S
> terminals are for remote sensing.  I take it the latter are unnecessary
> unless very long power leads are used. (?)

It depends on voltage drop in the wiring,  and how important accuracy is to 
you.  If the wires are a bit undersized then you'd want to do that to ensure 
tha the exact voltage at the load is what's there,  but this being a 
relatively low-current supply and you not building some kind of 
instrumentation there I wouldn't say you needed it.  However,  you _do_ need 
to connect each sense terminal to its corresponding output,  for it to 
regulate properly.

> I've had a thorough look at the datasheet, and no guidance is given there
> for these terminals either.

No schematic?

> While I've got your attention, perhaps you can tell me about the standard
> way to connect the output terminals to the distribution board.  I'm looking
> at the picture of the MOTM-900 (http://www.synthtech.com/motm900.html,
> click embedded picture) but I can't make out what the connectors are either
> on the board or on the supply terminals.  I'm guessing the terminals on the
> board are flat slip-on tongues like those on the Power-One transformer. 
> I'll have to look for those at my friendly neighborhood electronics store.

It looks like it.  The version they're using there are the ones that are fully 
insulated over the entire outside of the connector,  rather than having the 
metal bit bare.  This sort of part makes a lot of sense if you're dealing 
with the power line,  on-off switch,  and related stuff,  which is what I 
guess I'm looking at in the picture there.

That pic also confirms my guess as to the type of terminal you have for output 
on the power supply,  those just get wires soldered to 'em.

I'd put the jumper wires to the sense inputs on there _first_,  that way if 
you ever decide to change the wires for the outputs you won't have to disturb 
them.

If you find yourself maybe likely to use a bunch of any given kind of these 
connectors it gets way cheaper to buy a box of 100.  The last one of those I 
got were "red" butt splice connectors for when I was working on my truck's 
wiring,  and I got 'em at a hardware store.  Those little packages that may 
have only a half-dozen or so connectors in them are way more expensive for 
each piece by comparison.

> The Power-One output terminals are shown quite clearly in the picture, and
> those which are connected appear to have heat shrink tubing on them, but I
> don't know how the leads are actually attached.

They're soldered on to those terminals.  Heatshrink there will only protect 
the supply.  I'd be more concerned about protecting accidentally touching the 
AC power line and using some on the wiring there,  unless you get the 
fully-insulated terminals shown in the picture,  though they're a bit more 
spendy than the regular ones.

> Any help much appreciated!
> Dave
>
> > > Looking at my new Power-One +/-15V, 1.5A power supply, I have two
> >
> > questions:
> > > 1.  Do you solder 120VAC leads to the flat terminals sticking out of
> > > the transformer, or do you slide something onto them without soldering?

You *could* solder on to those,  or use the push-on terminals on the ends of 
the wires,  either way.

> > > Is it a good idea to put shrink tubing on them afterwards?

See above.

> > The flat tabs are mostly likely Fast-on terminals. You want to get the
> > insulated crimp terminals and then a small crimp tool like an AMP Champ.

That's what I use,  one of those...  :-)


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