IBM 029 Keypunch has arrived

[Tony Duell]

> 
> The rating plate shows .4kVA which is more than my Flexowriter  
> transformer can handle so I have ordered a modern yellow industrial  
> 110v socket so I can try it on a 3kVA transformer I have for an angle  

I assume you want a 110 _plug_ here to fit your tool transformer.

The output of such transformers is centre-tapped to ground, that is 
neither side is groudned (or close to ground). Most stuff doesn't mind 
this, but I'd check the schematics to be sure.

> grinder. I have searched though eBay for normal US wall sockets and to  
> my surprise cannot find them. I've tried all sorts of search terms but  
> obviously have not hit the right combination, unless there is some law  
> which prohibits them being sold retail or something like that.  
> Probably me being stupid.

IIRC the brand name to look for is 'Hubble'

I seem to rememebr RS components sell the cable-mounting version, but they 
are fairly expensive. 

Alteratively by an 'exension cord' as they're  called in the States and 
cut the plug end off and wire it to your BS4343 plug.

> 
> Looking through the parts list there is something I'd like the list's  
> opinion on. The diagram shows a transformer but the list says  
> "REGULATOR ASM, FERRORESONANT-60CPS 120VA" and a similar option for  
> 50Hz which of course I don't have. What are these for? Might they work 

Ferroresonant transformers have an extra secondary winding resonated to a 
harmonic of the mains freqeucny by a capacitor (normally clamped to the 
transfomer core). Such transformers have a fairly stable output voltage, 
which is why they're used in older competer equipment when electronic 
regulators were complicated and expensive.
 
> at the wrong frequency? Will they be damaged or just not work? This is

They certainly won't work properly at the wrong frequency.

If you are lucky there will be multiple taps on the 'capacitor' winding 
for different frequencies. If you're even luckier the tap setting will be 
docuemtned.

Something I've never tried, but which may well work is to regard said 
winding as a simple LC resonant circuit, remember that f ~ 1/sqrt(C) and 
thus calculate the new value of capacitor needed given the 2 frequencies 
and the size of the '60Hz' capacitor.  

-tony