Friday, November 17, 2023

Vintage Megger turned Self Torture Device

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We found this ~60 year old Biddle Megger while going through the closet.  It was used by my father's and was no longer working.  The fix was possibly something simple, but we don't need a Megger so the crank voltage transformer became more interesting.  

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Just for the heck of it we decided to mount the crank voltage transformer and discover what it could still do. 

We knew based on the dial setting on the Megger that an output of ~1000 Volts AC was possible.  To not cook any of our instruments during the test we built 100K:1K Ohm resistive divider to tame the signal.  This makes the amplitude of the crank voltage transformer output about 100 times smaller.

Here the results using the Moku:Lab as our measurement tool.  This was easy duty for the Moku which has an 13 amazing instruments in one box and worth reading about.

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Turning the crank as slow as we could yielded about ~480V RMS at 13Hz.   Touching the output terminals not was screamingly painful, but we did verify that it is uncomfortable to touch.

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Max output was ~800V RMS at 55Hz and we wisely decided not to sample the pain level of this output.

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