Neutral Grounding on Secondary of Step Down Transformer

[agubaira]

Hi everyone,

I´ve got the following connection scheme:

3 phase delta wired Generator --> Transfer Switch --> Main Panel --> single phase Step Down Transformer (220 to 110V) --> Load

(The reason to use a step down transformer is to reduce cable gauge because of voltage drop)

Now, the transformer is fed with 220V line voltage, no neutral. How do I go about getting a neutral at the secondary and where must it be bonded to ground ?

Thanks

 

[ActionDave]

Now, the transformer is fed with 220V line voltage, no neutral. How do I go about getting a neutral at the secondary

You get it from the transformer. If it is a standard transformer there will be X1, X2, X3, and X4 and you will parallel the windings.

and where must it be bonded to ground ?

Thanks

If you are working under NEC you would bond inside the transformer or inside the secondary disconnect.

 

[ptonsparky]

Hi everyone,

I´ve got the following connection scheme:

3 phase delta wired Generator --> Transfer Switch --> Main Panel --> single phase Step Down Transformer (220 to 110V) --> Load

(The reason to use a step down transformer is to reduce cable gauge because of voltage drop)

Now, the transformer is fed with 220V line voltage, no neutral. How do I go about getting a neutral at the secondary and where must it be bonded to ground ?

Thanks

You have a separately derived system so you develop one at the transformer by earthing one of the secondary lines via your GES. X2 is typical for single output. What size of transformer are you using? Larger 240/120 will have x1 x2 x3 x4 as choices. Look at the installation instructions for the transformer. Read the Fine Manual.