Electrical Question For Our Friends Down Under.

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9,797
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Central Coast, Calif.
I build a machine that uses 120v 10a single phase. The load is resistive so the frequency won't make a difference. The PLC has its own power supply that converts 120-240vac into 12vdc. The resistive load uses a transformer that drops the 120vac to 6vac. I have a client in Australia interested in purchasing some of these machines but I am unfamiliar with electrical requirements outside of the USA. Is there a simple power supply that I can recommend to my client? I'd rather not rework the electrical system at this point.
 

MolaKule

Staff member
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21,908
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Iowegia - USA
http://www.armory.com/~stacey/aus-us-power.html
Quote:
The PLC has its own power supply that converts 120-240vac into 12vdc. The resistive load uses a transformer that drops the 120vac to 6vac.
So the PLC has a switching power supply that works from 110VAC to 240VAC?? It sounds as if the resistive load needs its own 240VAC to 6VAC transfformer. Recommend you fuse input to transformer or SWPS to 1.5X operating current.
 
Last edited:

tom slick

Thread starter
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9,797
Location
Central Coast, Calif.
The PLC has a standalone power supply that will is rated 85-265vac 50-60hz input. Changing the transformer for the resistive load (heaters) is possible but easier said than done. The most cost effective solution seems to be using a transformer/power supply to drop the 240v to 120v so everything could be plug and play. I am unfamiliar with whatever the Australian version of NEMA is and what their standards are.
 
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11,656
Location
Illinois
You will be using a transformer either way. Sounds like you don't want to replace the "internal" transformer for the resistive load. Using an external transformer/power supply is doing the same thing you would be doing if you used a different transformer inside. I'm with MolaKule, a different transformer for 220v applications is in order. Makes it ready for deployment in a number of places worldwide where 220v electricity is the standard. Is it possible to source a transformer that has a center tapped secondary. You could use a switch to determine where you take your 6vdc. If it's set to 220v input, you take it from the center tap on the secondary. If set to 110v, you take it across the entire secondary. This way, the product is ready for the world with the flip of a switch.
 
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1,058
Location
New Zealand
It's fairly easy to source a 230VAC to 110VAC transformer downunder, although 1.2 KVA is getting up there in size. I have a building site transformer on which I run a 110VAC laser printer. If it's a personal import for the buyer there should be no issues but if it's sold as a commercial product for anyone to buy it would likely have to have the correct mains connection provided, certified to Australian Design Rules (ADR). Amusingly I have a harder time convincing locals that US homes are wired for 220.
 
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