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 Post subject: Request Help to ID a Peerless Transformer
PostPosted: Nov Wed 13, 2019 4:44 am 
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Joined: Dec Wed 18, 2013 6:03 am
Posts: 325
Location: Inver Grove Heights, MN 55076
Hello All,

This was part of an estate lot and, unfortunately, the part number label is almost completely gone.

I have looked around in general web searches for Peerless output transformers (I am assuming that's what this is) and I do not find any photos with a circular opening for the leads. It looks to be the same size as the output transformer used on a Heathkit W5 - type of monoblock, but the pictures I see still do not match the large circular opening and this one has terminals instead of wire leads.

Here are some pictures:

Attachment:
DSCN5723 (Small).JPG
DSCN5723 (Small).JPG [ 106.7 KiB | Viewed 796 times ]


Attachment:
DSCN5724 (Small).JPG
DSCN5724 (Small).JPG [ 106.88 KiB | Viewed 796 times ]


Attachment:
DSCN5725 (Small).JPG
DSCN5725 (Small).JPG [ 101.27 KiB | Viewed 796 times ]



Any help/advice would be greatly appreciated.

Thanks in advance.

Best Regards,

Greenhorn


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 Post subject: Re: Request Help to ID a Peerless Transformer
PostPosted: Nov Wed 13, 2019 4:10 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4814
Location: Rochester NY USA
Start by finding the winding connections and resistance with an ohmmeter. Impedance can be measured by determining the winding ratios. If it works out to 5K, could be this: https://www.worthpoint.com/worthopedia/ ... -101639585

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 Post subject: Re: Request Help to ID a Peerless Transformer
PostPosted: Jan Thu 02, 2020 3:42 am 
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Joined: Dec Wed 18, 2013 6:03 am
Posts: 325
Location: Inver Grove Heights, MN 55076
Hello,

Tom: Thanks for your suggestion. This is the first time I have performed such an analysis. Poking around the web for instructions led me to this site: http://www.sarris.info/main/calculating ... -impedance

Here is the process I followed, step by step. All measurements were via a hand-held digital meter:

1. I removed the two wires that were soldered between pins 3/4 and 8/10.

2. Measured resistance between 1/2, 2/3, 3/4, 4/5, 5/6 on the primary side. Readings in ohms are below:

1/2: 94
2/3: 114
3/4: open
4/5: 103
5/6: 105

3. Similarly, I measured the resistance between the secondary pins 7 through 12. Readings in ohms are below:

7/8: 1
8/9: 0.7
9/10: open
10/11: 0.8
11/12: 0.8

4. I connected pins 3/4 and 9/10 with jumper leads.

5. Applied 25 VAC across pins 1/6.

6. Measured 1.32 VAC across pins 7/12.

7. 25/1.32 ~ 19:1 turns ratio

8. 19*19 ~ 360:1 impedance ratio

9. With a 16 ohm load, the input impedance is (16*360) ~ 5760 ohms, or roughly 5.8k ohm impedance.

With split primaries and secondaries, I imagine it is possible to create a wide array of input and output ratios.

Question for the community: Does my method and math work out reasonably well for typical output transformer values?

For push-pull amps I have seen ~5k input impedance for today's speaker loads of 4, 8, of 16 ohms. The link sent by Mr. Bavis mentions "Impedance, OHMSPri.: 5000 OHMS C.T. 250 OhmsSec.: 16C.T. 128 C.T. 4, 2". I suppose different primary and secondary connections would enable such values, allowing for a bit of variation in math due to a relatively low-tech voltmeter.

Thanks in advance for any helpful comments and suggestions. I am still looking around the web for Peerless documentation but have had no luck finding anything for this transformer thus far.

Best Regards,

Greenhorn


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 Post subject: Re: Request Help to ID a Peerless Transformer
PostPosted: Jan Fri 03, 2020 2:31 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4814
Location: Rochester NY USA
The attached is part of a page from a 1953 general distributor catalog; the Peerless catalog should have more, including the connections. The S226 and S-256 are the suspects, impedance seems to be halfway between the two but dimensions are different, which may settle it.

Attachment:
Peerless.jpg
Peerless.jpg [ 598.69 KiB | Viewed 546 times ]

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 Post subject: Re: Request Help to ID a Peerless Transformer
PostPosted: Jan Fri 03, 2020 3:38 am 
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Joined: Jun Wed 08, 2011 2:33 am
Posts: 10676
Location: Ohio 45177
Wonder if there are any markings or stampings on the actual transformer inside the can. Can you disassemble it for examination by removing the screws? Stancors have that fancy yellow sticker on the top of the bracket to identify the unit and those tend to fall off. Then there is the number stamp on the insulation on the sides. I used that the other day to spec an audio output in a radio I was salvaging. Someone had used the Stancor to replace the original.

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 Post subject: Re: Request Help to ID a Peerless Transformer
PostPosted: Jan Fri 03, 2020 4:07 am 
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Joined: Nov Sun 04, 2007 6:01 am
Posts: 3566
Location: Redding, CA
Except for the secondary that does not appear to have enough taps, my vote is for the S-226Q. The primary of your transformer is set up for two impedances, one series connected and the other parallel connected for 1/4 the impedance of series connected. What is the weight of the transformer?

Norman

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 Post subject: Re: Request Help to ID a Peerless Transformer
PostPosted: Jan Sat 04, 2020 4:01 am 
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Joined: Dec Wed 18, 2013 6:03 am
Posts: 325
Location: Inver Grove Heights, MN 55076
Hello All,

Thanks for the tips.

The dimensions of my transformer are about 3 1/32" x 3 1/8" x 4 1/8" (including screws and terminal posts).

Weight is about 4 pounds, 2.5 oz.

So the size is essentially the same as listed for the S-226-Q, but the actual weight is heavier than what is listed in the catalog by nearly a pound. With the weight of my transformer being around 4 pounds, it cannot be either of the S-256-Q or S-268-Q.

I did open the top lid, but there was no label or stamp on the underside.

Thanks again for everyone's help. I really appreciate it. I will keep looking, but this may be a lost cause.

Best Regards,

Greenhorn


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