[AMRadio] Chicago Standard Transformer

Byron bjtatum1 at att.net
Tue Mar 8 19:46:22 EST 2016

   I was hoping someone may be able to help me identify a transformer by Chicago Standard. This transformer is NOS and the terminals have never been soldered to. Here are some details:
1. Transformer is hermetically sealed, about 6” tall by about 4” square weighing about 20#. Is painted black and labeled Chicago Standard Transformer. 
2. Does not have the transformer diagram painted on side or top like most hermetically sealed ones do. Has 4 of #10 mounting studs on bottom. 
3. All terminals are on bottom of transformer. Has 3 high voltage ceramic insulated terminals in one row labeled 1, 2 and 3. There is 78 ohms between 1-3. There is 37 ohms between 1-2 and between 2-3. I am assuming this is a HV winding.
4. There are 3 rows of smaller, lower voltage ceramic insulated terminals spaced away from HV terminals. There are two rows of 4 terminals and one row of 3 terminals. These are labeled 4 through 14. All of these terminals have continuity to each other. If I measured from 4-14 I get the greatest resistance which is 0.4 ohms. There is either 0 or 0.1 ohms between any consecutively numbered terminals; probably some variation in my meter and probes contacting transformer terminals. Terminals 4-14 appear as one winding with many taps.
I have not tried to put any voltage on this unit. Normally I will use a 5 VAC filament transformer to power a HV transformer primary. However, I am not sure of this transformer type. The very low resistance of terminals 4-14 suggest a 115 or 230 VAC primary, and the 78 ohms between 1-3 suggest a HV winding. 
	There is no conventional Chicago or Stancor part #, it only has the numbers 20208 stamped on underside.
      Byron W5FH

More information about the AMRadio mailing list

This page last updated 20 Nov 2017.