Can a Zig-Zag Transformer Provide a Neutral for 3-Phase HVAC Control Circuits?

AI Thread Summary
A zig-zag isolating transformer can provide a neutral point for a 3-phase HVAC control circuit where only a 3-phase supply is available. The control circuit requires approximately 15A at 230V, and proper sizing of the transformer is essential for safe operation. It's recommended to consult with a licensed electrician for assistance with installation and sizing. Additionally, users are encouraged to seek manufacturers that supply zig-zag transformers suitable for their specific needs. Proper guidance and professional support are crucial for ensuring compliance and safety in this project.
halam
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Hi

We have a project where we have to install an HVAC system but only a 3-phase supply is available. While that is fine for the motors inside the unit, it means that there is no neutral available for the control circuitry.

I am aware that a "zig-zag" isolating transformer can provide a neutral point in a 3 wire system but I have not used it before.

The control circuit will require approx 15A, what is the correct method of sizing the transformer, also is there any manufacturers out there that can provide this product?

Attached is a possible solution, as it mentions the zig-zag option. Would this fulfill the requirement?

Some details for our project:
Available supply: 3ph 400V (400A Breaker)
Control Circuit: 1ph 230V (24no 230V Contactors & 4no Siemens PLCs - Approx 15A)
 

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halam said:
Hi

We have a project where we have to install an HVAC system but only a 3-phase supply is available. While that is fine for the motors inside the unit, it means that there is no neutral available for the control circuitry.

I am aware that a "zig-zag" isolating transformer can provide a neutral point in a 3 wire system but I have not used it before.

The control circuit will require approx 15A, what is the correct method of sizing the transformer, also is there any manufacturers out there that can provide this product?

Attached is a possible solution, as it mentions the zig-zag option. Would this fulfill the requirement?

Some details for our project:
Available supply: 3ph 400V (400A Breaker)
Control Circuit: 1ph 230V (24no 230V Contactors & 4no Siemens PLCs - Approx 15A)

Welcome to the PF.

You need to use a licensed electrician to help you with this project. We cannot help you here.
 

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