I have a question about an Isolation transformer wiring diagram and need some help figuring it out. My main question is on a 240V input to 240V output where do I connect S1 and S2? I understand I connect H3-H2 and use this as the neutral in and then H1 and H4 as the 2 hot legs but where do I connect S1? It will be the same configuration on the output but where do I connect the S2 on the output?


Below are pictures of the current way I have it set up but I am not sure it is correct.
Input:


Output:


Any help would be appreciated!!!

Thanks

 

If you want galvanic isolation do not connect the S1/S2 link.
If used it is no longer an Isolation Transformer.
Max.

 

You're Wrong with the input terminals, H1 and H4 are your 240V input, H2,3 are linked but not used.
Don't connect S1,S2
See the chart on the side!!

 

The way I read this is: S1 and S2 are shields between the windings and the magnetic core material. They can be grounded to stop high frequency noise pulses from coupling capacitively from the primary to the secondary. Connecting the shields to one leg of the 240V line doesn't make sense to me. That would actually increase the coupling of high frequency noise from the input to the output.

 

@Stills00 If you want to re-establish the neutral, then re-reference one side of the secondary to earth ground in order to re-establish a neutral, connect one terminal of the secondary to the service earth ground, this conductor then becomes a local neutral.
Max.

 

If you want galvanic isolation do not connect the S1/S2 link.
If used it is no longer an Isolation Transformer.
Max.

I am using this as a line noise reducer for a cheap hole house generator to try and clean up some of the line noise coming from my generator prior to entering the House Panel. Not sure if I want a galvanic isolation or if I do? haha

 

You're Wrong with the input terminals, H1 and H4 are your 240V input, H2,3 are linked but not used.
Don't connect S1,S2
See the chart on the side!!

That is what i am trying to figure out I know that I use H1 and H4 for the hot wires and connect H2 and H3 together but the real question is what do i do with S1 on the input and output.

 

The way I read this is: S1 and S2 are shields between the windings and the magnetic core material. They can be grounded to stop high frequency noise pulses from coupling capacitively from the primary to the secondary. Connecting the shields to one leg of the 240V line doesn't make sense to me. That would actually increase the coupling of high frequency noise from the input to the output.

So you understand my hesitation to follow the schematic!!! i already have the ground wire connected to ground on both sides so would i also connect the S1 and S2 to the grounding Lugs?

 

Leave S1,2 not connected, that way there is total isolation.

 

@Stills00 If you want to re-establish the neutral, then re-reference one side of the secondary to earth ground in order to re-establish a neutral, connect one terminal of the secondary to the service earth ground, this conductor then becomes a local neutral.
Max.

I was told by a friend that the H3&H2 and X3&X2 would be my neutral through the unit.....

 

That is what i am trying to figure out I know that I use H1 and H4 for the hot wires and connect H2 and H3 together but the real question is what do i do with S1 on the input and output.

I think I was mistaken about S1 & S2, as per @#12 I think they are shielding but there does not appear to be terminals labeled as such?
If this is a whole (hole?) house generator and you are connecting to the service panel then you should not need the earth (re)referencing.
Here is a similar recent thread https://forum.allaboutcircuits.com/threads/what-connections-should-i-make-for-220v-output.134721/
Max.

 

Ok so here is what I am trying to do:

I have a Generator (harbor Freight, I know, I know why did I buy that piece of crap, it was $500 and I didn’t want to spend $2K on a good one) and I have a Smart Home with integrated Z-wave switches. My power goes out sometimes and I want to use the generator to power up most of my house.

I currently have the generator plugged into a sub panel that feeds back to the main and after doing some testing on it with my neighbors oscilloscope found that it is pretty close to a sine wave but want to clean it up a bit. So my neighbor suggested an isolation transformer to help clean it up to make me feel more comfortable with all the electronics in the house. So I found this one on eBay for $150 and it is 5KVA and it will satisfy my power needs with margin.

I took the 4 prong 240V generator extension cord cut it in half and plan to put this transformer in between the generator and the panel. So I have 2 hots, 1 neutral and a ground coming from the generator into the transformer and then the same on the output going to the sub panel. The ground and neutral have been split at the sub panel, with a code approved grounding rod, and they are also split at my main panel.

I know that was a long read but what I am trying to do is clean up the sine wave coming out of the generator and into the house so I don’t smoke all of my smart home stuff in a power outage.

 

So it sounds as though you are in N.A.? If so then the X2-X3 C.T. connection will be connected to panel earthed neutral?
Passing it through a transformer will provide some harmonic suppression but I don't think it will change the 60Hz wave form a great deal.
Max.

.

 

So it sounds as though you are in N.A.? If so then the X2-X3 C.T. connection will be connected to panel earthed neutral?
Passing it through a transformer will provide some harmonic suppression but I don't think it will change the 60Hz wave form a great deal.
Max.

.

N.A.? I live in California

 

Last time I checked it was in N.A. (North America).
This is why it helps to show your country of origin
Max.

 

Last time I checked it was in N.A. (North America).
This is why it helps to show your country of origin
Max.

Good point! hopefully it is visible now.

X2 and X3 will be connected to a gound at the main Panel.

So if I remove the S1&S2 wire from the rerminals that I currently have them on in the transformer and cap them then the setup in the pics will work for my needs?

 

Leave S1,2 not connected, that way there is total isolation.

Then what is the S1 and S2 even for? Why whould they include it if it doesnt do anything?

 

Then what is the S1 and S2 even for? Why whould they include it if it doesnt do anything?

They are for shielding against emf radiation noise, but for an Isolation transformer you don't need an earth on the secondary side.

 

Isolation transformer you don't need an earth on the secondary side.

If he is connecting the secondary to a N.A. service panel, the C.T. X2-X3 will automatically be earth grounded.
The N.A. residential service is a 240v 1ph transformer, with a CT at 120v, this CT is taken to earth ground at the panel where it is also taken off as a 120v neutral..
Max.

 

They are for shielding against emf radiation noise, but for an Isolation transformer you don't need an earth on the secondary side.

But I will have a ground on the secondary side for my setup that I detailed below.

Ok so here is what I am trying to do:

I have a Generator (harbor Freight, I know, I know why did I buy that piece of crap, it was $500 and I didn’t want to spend $2K on a good one) and I have a Smart Home with integrated Z-wave switches. My power goes out sometimes and I want to use the generator to power up most of my house.

I currently have the generator plugged into a sub panel that feeds back to the main and after doing some testing on it with my neighbors oscilloscope found that it is pretty close to a sine wave but want to clean it up a bit. So my neighbor suggested an isolation transformer to help clean it up to make me feel more comfortable with all the electronics in the house. So I found this one on eBay for $150 and it is 5KVA and it will satisfy my power needs with margin.

I took the 4 prong 240V generator extension cord cut it in half and plan to put this transformer in between the generator and the panel. So I have 2 hots, 1 neutral and a ground coming from the generator into the transformer and then the same on the output going to the sub panel. The ground and neutral have been split at the sub panel, with a code approved grounding rod, and they are also split at my main panel.

I know that was a long read but what I am trying to do is clean up the sine wave coming out of the generator and into the house so I don’t smoke all of my smart home stuff in a power outage.