You have the Hypersil version that looks like it is coated with some thick
black stuff. The models are
76A....2 tube standard xformer.
76PA.... 3 tube, standard xformer.
76PAC,,,, 3 tube, Hypersil xformer.
I have it on good authority that one can run full power with the 76PAC at 50Hz
with no problems at all. I would not hesitate to do that with mine if allowed,
and my tests confirm this. I have seen 76 run at 3kw and u could still put ur
hand on the air output. Remember Alphas are also sold to labs (one I know of
puts RF on plants to stimulate growth) where no one worries but just adjusts
full power and runs it for weeks like that in the experiments, etc. Relax
and LOAD IT UP.... that is what Alphas are for.
73,
Charles Harpole k4vud@hotmail.com
> From: km1h@jeremy.mv.com
> To: g3jvc@jcleeve.idps.co.uk; amps@contesting.com
> Date: Fri, 23 Apr 2010 21:11:43 -0400
> Subject: Re: [Amps] Transformer 50/60hz
>
> Id say you are good to go as received John considering that the 76 was
> shipped worldwide and used in contests and DXpeditions. If you have the
> Hypersil transformer option even better.
>
> The blower runs at reduced voltage thru a bucking winding in the transformer
> to reduce noise, you can bypass that if you wish. At 400W you can probably
> have the wheel almost at a standstill and have sufficient cooling (-;
>
> A transformer rewinder will have no problem with that sealant, its easy to
> remove for those shops but I doubt you will need their services.
>
> Enjoy it. I have the 3 tube version on the 2nd station.
>
> Carl
> KM1H
>
>
>
> ----- Original Message -----
> From: "John E. Cleeve" <g3jvc@jcleeve.idps.co.uk>
> To: <amps@contesting.com>
> Sent: Friday, April 23, 2010 8:24 PM
> Subject: [Amps] Transformer 50/60hz
>
>
> > Thank you Carl K1MH, Vic K2VCO and VK3PA for their response to my
> > question.
> >
> >
> >
> > The transformer fitted to this example of the 76PA is the more efficient
> > option that was on offer at the time of manufacture. Should the
> > transformer
> > fail, I do not think it could be rewound because it has a thick black
> > coating, it has most likely been impregnated and then dipped. In the UK
> > the
> > amplifier will not be run at more than 400w and so the power supply will
> > not
> > be stressed, but the losses within the transformer, manifesting as heat
> > are
> > of concern to me. But I had realised that the fan would turn slower when
> > running on the 50hz supply and part of my refurbishment plan is to change
> > the fan to a DC unit with the equivalent or greater air flow, which may
> > help
> > with the transformer heating.
> >
> >
> >
> > However, I think that my first experiment will be to power up the
> > transformer on its own, before installing it into the amplifier, and see
> > just how hot it becomes, keeping a close check on it, say every 15
> > minutes,
> > if it gets warm to the touch, but no warmer, and remains that way, then I
> > will install it into the amplifier. But, if it gradually gets hotter, to
> > the
> > point where you could "fry and egg on it", that would mean I will have to
> > obtain the 50hz replacement.
> >
> >
> >
> > Thank you once again for your advice, sincerely, John. G3JVC.
> >
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