ZW Transformer Type R

[Anonymous]

To add to my previous post, later production type Rs have "Model R" stamped on the lower case beneath the A-D row of terminals.

[lionelsoni]

I agree that what's important is what's inside.  But he asked how they could tell from a quick glance at the outside.

I doubt there's much reason to prefer one over the other, unless buzzing from the transformer annoys you.

[eZAK]

Good observation Jim!

I thought all ZW's were riveted.

[Anonymous]

Check the coil laminations, type R's have their lamination stacks riveted together.  This makes them more efficent and quiet.  The rivets are visible on the roller sides of the secondary coil.

[eZAK]

Locomods,

You are correct. The only true way to determine an 'R' is by the CB.

As Bob points out, name plates can be changed.

[lionelsoni]

The nameplate (ZW-21) and escutcheon (ZW-20) of the earlier transformer are combined into a circular nameplate (ZW-181) held on with a rivet (20-49).

[Locomods]

I'm new to the forum and have a basic question. How do I determine if a ZW is a type R?  My repair book states that the R type had the Bakelite circuit breaker instead of a newer disc type. It further states the Bakelite type is more dependable and reliable.  Is that all there is to it? I have had "experts" look at what I believe to be an R type (Bakelite CB is in there!) and state it is not so (just by looking at the outside).....How can they tell?