Yahoo Groups archive
Thread
2011-07-17 by tim p
Hi everyone I've recently converted an MKS-70 from US 117 to UK 240v, a simple job as the transformer had 240v taps. I've decided to convert my US rated PolySix, but the internal transformer does not have 240v taps. Can anyone please help with recommendation of a transformer they have used to successfully convert to UK? Thanks! Tim [Non-text portions of this message have been removed]
2011-07-17 by Andrew Jury
If you can¹t work this out for yourself then I would be very carefully poking around on the primary side of the mains supply!! However, as long as you promise not to sue anyone if it goes wrong then the 50VA transformer with 2 x 25v secondary windings might be what you are looking for. Cheers, Andy On 17/07/2011 13:44, "tim p" <target9@hotmail.com> wrote: > > > > > > > Hi everyone > > I've recently converted an MKS-70 from US 117 to UK 240v, a simple job as the > transformer had 240v taps. > > I've decided to convert my US rated PolySix, but the internal transformer does > not have 240v taps. > > Can anyone please help with recommendation of a transformer they have used to > successfully convert to UK? > > Thanks! > > Tim > > > > [Non-text portions of this message have been removed] > > > > > [Non-text portions of this message have been removed]
2011-07-17 by tim p
Hi Andy Thanks for that :0) I've converted a number of US machines to UK voltage and repaired various faults on my gear successfully (vintage kit needs maintenance). Was just wondering if anyone had a particular recommendation of a specific model transformer for the PolySix in respect of it's build and desirable noise characteristics. Cheers! On 17 Jul 2011, at 15:49, "Andrew Jury" <andy@networkjabber.com> wrote: > If you can’t work this out for yourself then I would be very carefully > poking around on the primary side of the mains supply!! However, as long as > you promise not to sue anyone if it goes wrong then the 50VA transformer > with 2 x 25v secondary windings might be what you are looking for. > > Cheers, > Andy > > On 17/07/2011 13:44, "tim p" <target9@hotmail.com> wrote: > > > > > > > > > > > > > > > Hi everyone > > > > I've recently converted an MKS-70 from US 117 to UK 240v, a simple job as the > > transformer had 240v taps. > > > > I've decided to convert my US rated PolySix, but the internal transformer does > > not have 240v taps. > > > > Can anyone please help with recommendation of a transformer they have used to > > successfully convert to UK? > > > > Thanks! > > > > Tim > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > [Non-text portions of this message have been removed] > > [Non-text portions of this message have been removed]
2011-07-17 by y964omw
Hi Tim, Not really sure what to suggest here. A standard ferrite core transformer has worked OK in the past for many years, so anything suggested below should work OK. If you are worried about the mains input clarity then you might want to look at the filtering arrangement on the input side. There is already a 'spark killer', but a nice T or Pi filter in a screened can might be better. Also, how about going down the hi-fi nut route and fitting a torriodal type. Very low loss and efficient! Bye, Andy --- In PolySix@yahoogroups.com, tim p <target9@...> wrote:
> > Hi Andy > > Thanks for that :0) > > I've converted a number of US machines to UK voltage and repaired various faults on my gear successfully (vintage kit needs maintenance). > > Was just wondering if anyone had a particular recommendation of a specific model transformer for the PolySix in respect of it's build and desirable noise characteristics. > > Cheers! > > > > > > > > > On 17 Jul 2011, at 15:49, "Andrew Jury" <andy@...> wrote: > > > If you canât work this out for yourself then I would be very carefully > > poking around on the primary side of the mains supply!! However, as long as > > you promise not to sue anyone if it goes wrong then the 50VA transformer > > with 2 x 25v secondary windings might be what you are looking for. > > > > Cheers, > > Andy > > > > On 17/07/2011 13:44, "tim p" <target9@...> wrote: > > > > > > > > > > > > > > > > > > > > > > > Hi everyone > > > > > > I've recently converted an MKS-70 from US 117 to UK 240v, a simple job as the > > > transformer had 240v taps. > > > > > > I've decided to convert my US rated PolySix, but the internal transformer does > > > not have 240v taps. > > > > > > Can anyone please help with recommendation of a transformer they have used to > > > successfully convert to UK? > > > > > > Thanks! > > > > > > Tim > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > [Non-text portions of this message have been removed] >
2011-07-17 by Ben Stuyts
On 17 jul 2011, at 16:48, Andrew Jury wrote: > If you can’t work this out for yourself then I would be very carefully > poking around on the primary side of the mains supply!! However, as long as > you promise not to sue anyone if it goes wrong then the 50VA transformer > with 2 x 25v secondary windings might be what you are looking for. Are you sure about the 2 x 25 V? In my schematic there are some caps behind the rectifier which are only 35 V. (25 V x sqrt(2) - 0.7 V diode loss = 34.7 V.) And with less load or over voltage on the input the transformer output could be even 10 % or 20 % higher and you would blow the caps. My guess is you would need only 2 x 16 V, 40..50 VA. Anybody here actually measured the output voltage of the transformer? By the way, if you open up the Polysix, it might make sense to recap the power supply board anyway. And make sure to check the battery. But you probably know that. :-) Kind regards, Ben
2011-07-17 by Andrew Jury
Sums up my point perfectly! If you are unable to do the maths yourself you shouldn't be in their tinkering! BTW. Multiplying the secondary input AC by 1.414 is a much easier way to remember and I get 35.35V. So yes, BANG! Cheers, Andy
On 17/07/2011 23:15, "Ben Stuyts" <ben@stuyts.com> wrote: > > On 17 jul 2011, at 16:48, Andrew Jury wrote: > >> If you can¹t work this out for yourself then I would be very carefully >> poking around on the primary side of the mains supply!! However, as long as >> you promise not to sue anyone if it goes wrong then the 50VA transformer >> with 2 x 25v secondary windings might be what you are looking for. > > Are you sure about the 2 x 25 V? In my schematic there are some caps behind > the rectifier which are only 35 V. (25 V x sqrt(2) - 0.7 V diode loss = 34.7 > V.) And with less load or over voltage on the input the transformer output > could be even 10 % or 20 % higher and you would blow the caps. > > My guess is you would need only 2 x 16 V, 40..50 VA. Anybody here actually > measured the output voltage of the transformer? > > By the way, if you open up the Polysix, it might make sense to recap the power > supply board anyway. And make sure to check the battery. But you probably know > that. :-) > > Kind regards, > Ben > > > > ------------------------------------ > > The original Poly6-mailinglist: http://www.acc.umu.se/~amber/Poly6/ > Yahoo! Groups Links > > >