Re: Maximum MOT`s power for long, reliable operation and life - how much is it?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "S&JY" <youngsters@xxxxxxxxxxxxxxx>

Another solution is to use another MOT, cut off the secondary, and wind
enough turns of #12 or #10 wire to output about 10 volts.  Then wire this 10
volt secondary as series-opposing with your MOT(s) powering your TC.  This
keeps the no-load voltage to your MOT(s) below the point where they draw 5
amps or so and cause the core to get very hot.

--Steve Y.

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Thursday, July 07, 2005 1:51 PM
Subject: Re: Maximum MOT`s power for long, reliable operation and life - how
much is it?


> Original poster: "Peter Terren" <pterren@xxxxxxxxxxxx>
> SNIP>
> If you look at the power consumption with input voltage you will see it
> rise very significantly by the time it gets to mains level (up to 4-5
amps).
> The solution is to use a variac or an external ballast or wind an extra
> 30-50 turns of wire in series with the primary for 240V mains and half
that
> for 110V.  The latter is only possible if you are removing the primary
though.
>
> Running under oil helps with the heat loss but not total draw.  My coils
> use 4 MOT's under oil but I watch the current draw. My best pic had the
20A
> meter hard over.
>
> Peter (Tesla Downunder)
> http://tesladownunder.com
>
>
>
> >Original poster: Grishka <ghome@xxxxxxxxx>
> >
> >There`re lots of articles in Internet, when people use MOTs as TC power
> >supply.
> >In all cases they draw more than 1 kW from one MOT, they say, operational
> >time is short (some minutes)... I then decided to find out, how many
watts
> >can give us one MOT in a continuos condition of operation.
> >I`ve recently made rather simple experiment - I`ve connected in series 10
> >incandenscent lamps (60 watt one piece), MOT was working 45 minutes, it`s
> >temperature  became 76 degrees! But - my mains voltage was only 206 volts
> >instead of 220 - and let`s imagine, what could happen with this
transformer at
> >full 220 volts?! A friend of mine (father dest) has tested such
transformer
> >with NO LOAD - after 20 minutes of operation transformer`s core was so
hot,
> >that couldn`t be touched by fingers for more than 5 sec! (mains voltage
was
> >226 volts, air temperature in the room - 28 degrees).
> >
> >According to these facts I have some questions:
> >
> >1 - does anybody know, how good is the wire insulation in MOT (varnish)?
> >That is - what temperature does this varnish can face without
considerable
> >decreasing its life time?
> >
> >2 - does MOT worth to be put into the oil? Can we consider oil as "a good
> >cooler"? Think about inner layers of HV winding - we can`t measure
temperature
> >right there...
> >
> >3 - In future I want to run my TC during 5 minutes continuous (minimum! -
it`s
> >better 10 or 15 minutes) with pauses not more than 10 minutes (with total
> >runtime about 1 hour). What power could we draw per MOT in such condition
> >without overheating? What is overhreating for you (see question #1)?
> >--
> >Best regards,
> >  Grishka                          mailto:ghome@xxxxxxxxx
>
>
>
>
>
>