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Vintage Transformer Test - Which Pins?

Trimglafix

May 11, 2022
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Hi all,
I have a vintage transformer as in the picture & detailed below.
I would like to test the transformer to see if it has any value, but I am uncertain as to where I should attach the 240V AC. I assume the live would go on the 240V pin & I am guessing the neutral would go on the SCR pin, but having never seen SCR before I would like confirmation so as not to risk damaging the item.
I am also keen to learn what SCR refers to; whether it is the correct terminal for neutral or not!

Thanks in advance.

Transformer Markings:
Gardners PK
R102/6
 

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kellys_eye

Jun 25, 2010
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No, AC mains NEUTRAL goes to '0' and LIVE to either the '220' or '240' pin depending on your local supply voltage. You can 'add' 10V by using the '10' pin instead of the 0 pin to get 230V or 250V as the input.

The OUTPUT are the terminals 250-0-250 (i.e. 500V center tapped) at 25mA max with a separate 6.3V 0.6A filament secondary above it.

I hope you are aware/familiar with working with AC mains and high voltage secondaries? If not then please find out or get someone else who knows!

SCR is the internal screen (between primary/secondary) and connected to earth when in use.
 

Trimglafix

May 11, 2022
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Thank you for your prompt reply kellys_eye.
I am pleased I checked first & you corrected my false assumption.

I am used to working with AC Mains (hobby, not professional) but not high voltage secondaries.
I am in the UK with a modern fusebox; therefore RCD protected - although I believe that won't help me on the secondary side of the transformer! I will be very careful though as, unlike @ElectroBoom, I hate receiving mains shocks & have managed to avoid them since last receiving one about 30 years ago!

My intention is to:
Connect 240V Live onto the only 240 pin (second row up).
Connect 240V Neutral onto the 0 pin (third row up - just above 240V pin).
Connect black probe to 0 pin on the fourth row up.
Connect red probe to 250 pin to confirm I have a reading on my meter set on 600V AC setting.
If I have a reading I will then do a test on the top two row pins on the 240V AC setting.

Assuming they all produce a reading I guess I can safely assert it is working (although I won't be confirming any amperage produced).
 

kellys_eye

Jun 25, 2010
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Gardner transformers are noted for their robustness and longevity so provided there is no obvious signs of overheating you'll probably find it works perfectly.
 

Trimglafix

May 11, 2022
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Joined
May 11, 2022
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Gardner transformers are noted for their robustness and longevity so provided there is no obvious signs of overheating you'll probably find it works perfectly.

Thanks again Kellys_eye.
I can confirm the transformer does indeed work, however the voltages read a bit high.
Mains direct measured at 240V
250V = 270V
500V = 541V
6.3V = 6.5V
All voltages were checked with 2 different digital meters & were within a volt of each other.
All readings were taken with no load on the output.
 
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