OK... Start from the beginning, again...
sorchard wrote:As you say, the original transformer is effectively 2 x 8.6 VAC. Max current is 1.8A per output coil. Power rating is 17.2 x 1.8 = 31VA.
I search on reichelt.de again...
I would like to insert the transformator into the case, at the place of the origin transformator.
There is a place of 6,4cm x 6,8cm (better 6,4cm), heigh: 6,5cm
Best matches are:
"Universal transformer" in a "open design":
A.) 2x9V 24VA - 15€
->
http://www.reichelt.de/Universaltrafos/ ... T+24VA+2X9
* size: 6x5,5x5cm (fit the origin place)
B.) 2x9V 48VA - 20€
->
http://www.reichelt.de/Universaltrafos/ ... T+48VA+2X9
* size: 6,7x7,5x5,9 cm (to big)
"Toroidal transformer" as a "print design"
C.) 2x9V 25VA for 18€
->
http://www.reichelt.de/Ringkerntrafos/R ... RKPT+25209
* size: 6x6x3,8 cm (fit the origin place)
"Closed PCB transformer":
D.) 2x9V 36VA - 10€
->
http://www.reichelt.de/Printtrafos-25-5 ... 6%2F23+209
* size: 7,1x6,1x4,9 cm (too big, but can be easy fitable)
E.) 2x9V 30VA - 10€
->
http://www.reichelt.de/Flachtrafos/UI-3 ... 9%2F21+209
* size: 6,8x5,7x3,5 cm (fit the origin place)
Seems that
D.) or
E.) is the best choice, isn't it?
E is smaller but the "problem" is, it has two primary windings: 2x115V... IMHO i can use it with 230V by "series connection", isn't it?
D is a little bit bigger, but has only one primary windings for 230V and is a little bit more efficiency...
So D?
sorchard wrote:If your house doesn't have circuit breakers you should probably include an inline fuse on the 230V side. Something like T2A with >1000A breaking capacity.
Adding a fuse is a good idea!
The 25VA "Toroidal transformer" has a fuse with 230V 160mA...
Should i add a fuse on both sides? primary and secondary circuit ?