Jump to content

Part Sourcing Assistance/Advice Thread


n_maher
 Share

Recommended Posts

I have D punches and the IEC punch.

 

yep they deform the metal but only on one side, so

you make sure the other side is the outside.

 

wrapping the die in some electrical tape along the

surface helps making no marks.

Wow IEC punch. Can you give punch maker/model (greenlee, ruko, qmax...) and corresponding IEC maker/model? I'll look into it.

Link to comment
Share on other sites

Checked rectangular knockout punches of many makers, couldn't find one that cuts hole for IEC at once (punch size and IEC size must match).

So will stick to RS 545-345 which is 28.2 x 22.5mm for my favourite Qualtek 764-00/002. Will have to cut 4 overlapping holes.

OEM is Manuform MA9730140.

BTW, they have MA9740040 which is 31.4 x 28.3 with radius corners, but that is 2 times more expensive.

Link to comment
Share on other sites

  • 2 weeks later...

navships on ebay has some wired that was contracted for the Trident Missile program, that stuff is really nice to work with. a bit stiff but it depends on what you're looking for I guess. I think it's a kapton wrap

I've used navships SPC wires a lot. Great stuff, cheap price but damn stiff. 

Link to comment
Share on other sites

I have a really really dumb question.

I would like to get as many turns of a trimmer over as small as a range as possible. For example, 25 turns over 1 ohm. What's the best strategy to do this, a series resistance to set the approximate value, then a resistor in parallel with a pot I assume, but how to size the pot (large or small) and the resistor, without having to do math is the question?

Link to comment
Share on other sites

sounds like a job for 2 pots in series with a resistor in parallel, are you actually shooting for 1 ohm? I assume it's something like 

 

(Npots*R) || Npots*R1 || ... || Npots*RN

 

Add one resistor in parallel for each pot you add in series to the chain? Sorry if I pulled a dumb in the formulation

Edited by nopants
Link to comment
Share on other sites

Well, the smallest commonly available trim pots appear to be 10 ohms, so you would have the fixed resistor plus the trim pot in parallel with a small value resistor, e.g. for a 1 ohm adjustment range, 1.2 ohms would give you an overall range between 0 and 1.07 ohms.  The adjustment won't be close to linear - about 1/2 the adjustment range would be in the lowest 10th of the trim pot range with hardly any change at all over the upper half of the trim pot range.

Edited by JimL
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...