Voltage conversion; need help please

[steve96822]

Acurus DIA 100 set up for 110voly (US)

Want to change it to 220v.

Have schematic but schematic depicts "switches" and unit does not have switches. Instead has a board. board has a different number of posts than schematic depicts.

anyone done this?

choices are 110, 220, 240v

Thank you

[AndrewT]

Hi,
can you post a pic of the wiring posts (pins) that feed the primaries?

[steve96822]

I will post a photo asap.

Thank you so much for your help.


Might it be possible to replace wiring post with some sort of switchable device so if i move back to a 110v location will not need soldering work?

[sletol]

Steve, I would in that case protect the switch from accidetal use, perhaps not make it available from the outside.
To your first question. All the pins, or soldering points, in question are connected to the same (primary) coil on the transformer. The different supply voltages are adjusted to by using the bigger or smaller section of the coil. Just find all the pins that are connected by measuring the DC resistance. (disregard the initial jump of the needle).
The 110V pins are using a smallest part of the coil, the 240V input is simply using the whole of the coil, and therefore has a higher resistance of course (or inductance for that matter), the 220 input slightly less. I cannot see that there is room for much error.
Using the 240 connection instead of 220 will probably not give any noticeable difference in practice, btw.

[jan.didden]

Possibly (probably) the 100V connection uses the two primaries in parallel. There is room for error: you need to connect them in the same phase, otherwise BOOM ..

Similarly for 220/240V the two primaries need to be in series, with the same phase, otherwise BOOM ..

Jan Didden

[sletol]

janneman, you are possible (probably) right! I take back what I said! But I wonder, if you by measuring the resistance first to find how to find how to couple the windings in series , would not the intrument at the same time reveal a potential wrong phase by an absence of the strong inductive reaction to the measuring current? In other words, would you not be able to find the right solution just by using a simple instrument?

[AndrewT]

Hi,
try reading this from yesterday
http://www.diyaudio.com/forums/showt...ht=#post998832
it may give you what you need.

[jan.didden]

Yes, you can measure the impedance with an AC voltage to see if you have it right. You either can use an L meter if you have it, otherwise use a signal generator and drive the primarie(s) with say 1kHz through 1kOhms, then measure the voltage at the primarie(s). The connection with the highest voltage is the right one (Ideally the wrong connection gives 0 volts ie a short).

Jan Didden

[steve96822]

see this and other photo

[steve96822]

photo B