Re: {Collins} An atypical Collins tale

If the lam size is still available it usually is not that great an idea to reuse transformer laminations. New lams of better spec are less than the labor involved. So you have a whole new transformer, unless you reuse the endbells.

 Winding new from scratch, saves a lot of work-there is no reason to unwind more than one to find out how it was done, especially with power transformers. 

 If you have a local wind shop, they will often wind a one off cheaper than the rewind places if you don't need it in a close time frame because they may have "Dead Spots" in the production schedule. 

 You will want them to add a few turns to the primary because nominal AC voltages have crept up somewhat in the previous five decades, a trend unlikely to stop.

> Richard, 
> That line is fused at only 3A for the as-built single winding 115VAC design
> and construction - not at all high. Just to be sure, however, in the
> rewinding that Gary is doing we will incorporated the two 115VAC windings
> but in parallel.  The transformer in its original form lasted 61 years, so
> with half the stress on the primary it will last at least 122 more :)
> Buzz  
> >
> >
> >
> > On 30 July I posted on this list without much hope of 
> > success a request for
> > a replacement T-402 low voltage transformer for my KW-1. 
> > As expected none
> > was found. The multi-winding transformer (800VAC/CT, 6.3 
> > VAC/CT and two 5.0
> > VAC secondaries) was obviously a "special" for Collins and 
> > its use made it
> > likely that it was for the unique design of the KW-1 only. 
> > So the
> > transformer had to be pulled in a bloody operation for a 
> > trip up to Gary's
> > Transformer Rewind Service hospital for treatment. On 
> > removing the
> > transformer there was a fascination finding. There was an 
> > extra pair of
> > wires exiting the transformer.  There wires were deeply 
> > buried into
> > factory-laced multi-wire bundles and after about 4 inches 
> > just ended. Gary's
> > examination has concluded that these wires were from an 
> > extra unused 115VAC
> > primary winding.   Why did this happen?  One can 
> > speculate, but one possible
> > explanation is that in an early design of the KW-1 Collins 
> > had the option,
> > as they do for the high voltage system of feeding the 
> > primary at either
> > 115VAC or 230VAC with the windings in series. The 
> > transformers were ordered
> > with the dual winding and then Collins made a decision for 
> > 115VAC only feed.
> > There still remains the possibility that there was another 
> > model transmitter
> > (commercial?) that did use the same secondaires but was 
> > designed for 230VAC
> > only,


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