New Arrivals 5.

Old UPS

I bought an old UPS without batteries mainly for getting it's enclosure for later projects. It cost me $10 delivered

It is Hungarian made from the "good old days". Disassembled it. The build quality was a real surprise to me. No welds, pop rivets, just machine screws everywhere. No soldering at the connectors, just proper terminals. No junk parts, just well known manufacturers one.

Made some calculations from the easily salvageable parts:

1x Omron G7L-2A-TUB relay. Current cost: $12.57 

1x DELTA 04BEEG3SA mains inlet with filter Current cost: $10.53

2x RICH BAY RG-02 mains outlet Current cost: $15.65 (for the two)

Together: $38.75

I also have a big power transformer and the enclosure itself.

I think it was a good deal.

Finally my 110 Tool arrived

No idea yet, when will I work on the lab's network, where I need this.

Triax connectors

It took a long time to get the triax connectors into my hands for the Keithley 236, but finally got it. On the Aliexpress I found one seller, who sell 5 pcs connectors on the price of one at Farnell.

Triax cable

Neither widely available nor cheep is the required triax cable. Not the wire core - insulation - shield - foil - insulation type (what on many places called triaxial), but the wire core - insulation - shield - insulation - shield - insulation type where the two shielding electrically insulated from each other.

Usually it is sold in large quantity (you need to buy the whole roll). Fortunately I found an 8m piece on the FB marketplace locally, for a few bucks.

It was horribly stinky (felt like a complete ashtray), but I was able to clean it up. When my Keithley 236 find its place in the lab, I'll build proper cables for it.

Dymo heath shrink

I wasn't aware that this thing even exists. I'm still in the rebuilding of my CNC router. It has markings on the stepper axis cables. I wasn't able to imagine, how those markings are made. Now I know. Somebody on an FB group shown it. As I have a USB Dymo printer, I immediately ordered a few packs in different sizes. When I get there to finish those cables, I'll use this as a marker.

47pcs unknown small transformer

(bought for $0.4 each)

As I have similar transformers, my assumption was, that I just need to measure while connecting to the 230V mains and I can use them. As I'm cautious guy, first I measured the coil DC resistance, just to have some idea. It come out 380 mOhm / 50 mOhm (primary/secondary). It is way too low for such transformer.

I have a same mechanical size 230V/230V transformer with 5,5 kOhm / 6,3kOhm coil resistance.

So the question is: what a hell this transformers are good for?

SMPS? Kind of filter? Something else?

No idea yet. There is two direction to figure out:

1. Disassemble one and see, what is in there (type of core, number of windings, wire diameter)

2. Measure.

I definitely choose the second option. I intend to measure inductivity, how it works on various frequencies, what is the ratio between the two coils, what is the highest achievable efficiency, where the core saturates, etc.

This is just a rough idea right now, how to measure. I intend to collect the following instrument park for this: A proper LCR meter, four DMMs, a power amplifier, and an oscilloscope, DC Load (I don"t have an AC Load, so a DC load with schottky diodes and filter capacitor would be good enough)

Here is some basic idea, what I intend to do (bit more, but this is good for starting):

https://www.youtube.com/watch?v=LWbHJoUrJWc