Re: MOT Measurements

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Paul Arrowsmith by way of Terry Fritz <twftesla-at-qwest-dot-net>" <p_t_arrowsmith-at-hotmail-dot-com>

Matthew
6 KV is not right, about 2.2 KV is what to expect.
To measure unloaded HV transformers I connect about 12V AC to the primary 
from a 12V 1A plugpack, measure the input and output voltages. Work out the 
step up ratio then multiply this by your supply voltage.
This is a simple, accurate, safe and cheap way to do this.
There should be no significant voltage drop with the transformer under its 
rated load so why bother measuring it?
Paul A
Australia

>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: MOT Measurements
>Date: Thu, 06 Dec 2001 08:01:19 -0700
>
>Original poster: "Matthew Smith by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><matt-at-kbc-dot-net.au>
>
>Hi All
>
>I was hoping to be able to report success with a potential divider that
>I have just built for my DMM, which allows me to measure transformer
>output up to 7kV (Vout=Vin/10), but...
>
>Despite having even labelled the wretched thing, I managed to connect
>the DMM probes across the wrong terminals.  There are now several tracks
>missing from the PCB inside my DMM - completely fried; it's going to be
>a long job with silver loaded paint to repair that!
>
>Nevertheless, if anyone wants instructions for a cheap ($15 Australian),
>simple and safe (although not idiot-proof) voltage divider, let me know
>and I'll post construction details and design notes on my site.
>
>Now, a question...  It looks like the MOT that I was testing is putting
>out about 6kV unloaded; is this normal?  Second question: what would
>make a good test load for the secondary to get a truer idea of the
>output voltage?  I know the technique of reversing the transformer (feed
>secondary, measure primary) but I want to do things this way round as an
>academic exercise.  Any pointers would be appreciated.
>
>Cheers
>
>Matthew Smith
>
>
>


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