Dual Voltage Transformer Fuses 1

[brinkmann27]

We are designing a small PCB with a dual voltage transformer. Customer would have a choice of input power. It's rated for 115/1/60 or 220/1/60. Primary connections have 4 pins. For the customer connections we will use pin 1 (L1) and pin 4 (L2). If we connect pin 1 and pin 3 ( for L1) and connect pin 2 and pin 4 (L2) we have a 115/1/60 volt input. L1 would be hot, L2 neutral. Or if we connect pin 2 and pin 3 (internally on the PCB with dip switches) The L1 and L2 connections would be for 220/1/60. For portection we would like to fuse the transformer. For the 220 volt it's no problem, fuse L1 and L2. For the 115 volt connection L2 would be neutral which we don't want to fuse.

Don't know if this is permissable, another idea would be to fuse one side of the secondary ( 24 V) and require the customer to provide branch circuit protection to the panel (transformer).

Any idea?

Thanks in advance!

 

[itsmoked]

Yeah a great idea... Just buy a 120/240 switch and solder it to the board! Otherwise you are going to be receiving blown boards to fix as users misconnect things.

Look at a Digikey.com part like EG1941 OR 42

There are others that actually have fuses incorporated in them too.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[automatic2]

provide L1,L2 and neutral terminals, fuse L1,L2. Include a two position slider switch that configures the terminal and transformer interconnect. Label your slider 115/220.

 

[brinkmann27]

Thanks Keith,

I think we'll use that switch and fuse one side of the transformer secondary.

 

[itsmoked]

Atta boy!

Oh hey, for future reference, there are much more sophisticated modules that allow US/foreign fusing where you have 120V verse 240 and as you switch things, it changes the fusing to boot. Generally they are IEC plug//fuse/switch modules.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[itsmoked]

Atta boy!

Oh hey, for future reference, there are much more sophisticated modules that allow US/foreign fusing where you have 120V verse 240 and as you switch things, it changes the fusing to boot. Generally they are IEC plug//fuse/switch modules.

WOW, my whole laptop just crashed - froze totally - I had to reboot it, yet Firefox asked "Restore session?" and came right back to what I'd just finished typing. SWEET!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[itsmoked]

Then I botched the submit.. Oh well.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com