Wiring a Transformer

[eric.k]

Hello all, I have a fairly simple question (i think)
I am trying to wire up a transformer I purchased to bring 120VAC to 12VDC, heres a link to the spec sheet of what i have
My simple question is how do i connect the ground (FG) and to where?
Thanks
E

 

[eric.k]

Also, sorry if this is in the wrong section!

 

[(*steve*)]

That's not a transformer, that's a power supply.

As far as I can see, there are 4 connections 2 for AC in, 2 for 12VDC out.

Connect the mains to the input (via a fuse and possibly a switch).

If your mains cable is earthed, connect the earth to the metal case. Or are you not using a metal case?

Before you do mains wiring you really should know what to do. Making a mistake with mains wiring can kill you or someone else.

If you have a mains cable, ensure it is properly secured. (This is a reason to use IEC connectors for the mains. They're easier to secure and if someone trips over the power cable, the cable will pull out.)

 

[davelectronic]

SMP's

Hello Eric.k.
Your transformer looks like a switch mode power supply, this is an electronic type transformer, not to be confused with a linear transformer of iron lamination and copper windings, your link gives two data profiles, each has five models on it from what i can make out, which model number is yours ?. secondly as it a switch mode power supply it will give you 12 volts DC if you have that model, there should be either two leads for the mains, one blue and one brown ( neutral / live ) or a pcb socket that takes a plug, usually to pins, sometimes more, depending on its manufacturers use, there may be variations on those colors, the input mains voltage is any where between 85 and 264 AC volts in.

The supply is suppose to be double insulated, meaning there is probably no earth or ground wire to connect up, its case must comply with installation standards in your country for safe use, i would advise you strongly not to connect it up until you have an enclosure for it.

The model number would be more helpful of the unit you have, and its intended use, as you give no indication. Dave.

 

[eric.k]

Thanks for the quick replies! And sorry for the misleading link, the model number of the supply I have is the VAF1012. On the board the +V and -V, AC(N) and AC(L) terminals are all identified, it is just the fifth terminal "FG" (which I assume is ground) that I would like to know how to properly/safely connect. This was not for permanent use just an experiment so I had not fashioned a metal case but I think I will do so now.
Thanks
E

 

[davelectronic]

SMP supply

Hi again.
If your case is metal it must be earthed, and your mains supply must incorporate the third earthing rail from the supply lines, no part of the supply can come into contact with the chassis or case if its metal, only the support holes in the pcb, be sure to check very carefully that no parts of the circuits pcb rails or tracks come in contact with the case, you can check for good earthing using a multi meters buzzer, before you power it up, if the case is plastic you might not have to earth it, but the design of the plastic case must be suitable for insulation on a mains voltage potential. Dave. PS with out a closer look of the pcb board i don't know if "FG" is ground for sure. A picture of the input would clear that up.

 

[Merlin3189]

See http://www.trcelectronics.com/Cosel/pdf/Manuals/vaf_manual.pdf

FG = frame ground
It appears to want to be attached to the mains earth, via the metal housing or directly if there is no earthed housing.
Don.