Thread: Step Down Transformer

Electric knife sharpener says to me
Dumb electric motor

If it has brains and computers ignore my thoughts
But if it’s a dumb induction electric motor I’d pop the cover and look at the specs on the actual motor

Orrr plug it in and see what happens !!!
If the smoke comes out I think you can buy a can of smoke at Jaycar

S

Originally Posted by Celtoid

Hi All,

Made a Rookie mistake and ordered an electric knife sharpener from the US. Has multi-language instructions, covers warranty in different countries, ships to Australia, etc. Unfortunately it turns up in US format ... US plug and 120V requirements.

Does anybody know of a place in Brissy that I can purchase a Tx that can handle 125W ... other than the ridiculously priced Jaycar items?

There are good options available in other cities in AUS (around $40) but would like to walk into the shop and buy.

Appreciated.

Kev.

Send it back and get one of these
Victorinox Wetzstahl Oval Diamond Coated Sharpening Steel 23cm | 7.8313 7611160705051 | eBay

Much easier on your knives, does a much better job of keeping a keen edge on your knives and NO need whatsoever to plug it in so you can even use it when you go bush

I have tried many differant types of knife sharpeners over the last 50 years and a whetstone and a GOOD steel is by far the most coveniant, easy and reliable option by Far

I still have an older (at least 15 years old) Victrinox diamond steel in with my killing knives set and it still does the job and I haven't had to use a whetstone on any of them since I got the diamond steel.

dick smiths (if you can find one) altronics, would be my gotos, office works has been known to carry them.

but heres a google search result of a bunch of other aussie places and then theres ebay...

240v to 120v step down transformer brisbane - Google တွင် ရှာရန်

Fair warning....

check what your appliance is and if you need an isolating or non isolating transformer, the isolation ones are dearer the non isolating ones about half the price for the same number of watts.

Originally Posted by Blknight.aus

dick smiths (if you can find one) altronics, would be my gotos, office works has been known to carry them.

but heres a google search result of a bunch of other aussie places and then theres ebay...

240v to 120v step down transformer brisbane - Google တွင် ရှာရန်

Fair warning....

check what your appliance is and if you need an isolating or non isolating transformer, the isolation ones are dearer the non isolating ones about half the price for the same number of watts.

Hi Dave,

Thanks for the input.

Dicky Smith is online only these days I believe. There is an Altronics in Virginia but they are asking $169 for a 250w. I'm sure their's and Jaycar's are good bits of kit that will probably go all day, but I only need something that will run off and on for 10 minutes every week or so. However, If I have to pay the bucks I will.

Fortunately there are a few online options in Aus, but having a new shiny thing, was wanting to play straight away .... you know how it is

The important thing in your post for me is the question around isolating and non-isolating. What does that mean? How do I tell? Is it when the device has no earth pin on the plug or are you referring to some sort of built in ELCB (or something similar)?

Thanks again.

Cheers,

Kev.

I think you'd be wasting money getting a transformer. Treat this as a learning exercise.

I assume from isolating and non-isolating, Dave means one has a transformer with separate 240v and 120v windings whereas a non-isolating might mean it's an autotransformer with a single winding, tapped at 120v, e.g., below pic.

What-is-an-Autotransformer.png

To be strictly legal, and safe, an autotransformer has to be an integral part of an appliance or other equipment. In other words, not something with an outlet on it that other things can be plugged into.
You need a double wound transformer which can be checked with a simple ohmmeter to show that there is no connection between the input and output.

Originally Posted by p38arover

What-is-an-Autotransformer.png

Whats here are both auto transformers and are what you need if you are going to be using an earthed appliance (caveats apply) and expect to have your RCD's work

Originally Posted by Celtoid

Hi Dave,

Thanks for the input.

Dicky Smith is online only these days I believe. There is an Altronics in Virginia but they are asking $169 for a 250w. I'm sure their's and Jaycar's are good bits of kit that will probably go all day, but I only need something that will run off and on for 10 minutes every week or so. However, If I have to pay the bucks I will.

Fortunately there are a few online options in Aus, but having a new shiny thing, was wanting to play straight away .... you know how it is

The important thing in your post for me is the question around isolating and non-isolating. What does that mean? How do I tell? Is it when the device has no earth pin on the plug or are you referring to some sort of built in ELCB (or something similar)?

Thanks again.

Cheers,

Kev.

iNKXW.png

thats the schematic for an isolating transformer, and with it come restritions, you cant use it for earthed appliances, it has to be double insulated from the wall to the end device, it cant have earth pins on the output side, the input side can only have an earth pin if its there to act as a safety interlock (some industrial sockets will not allow a plug into them unless there is an earth pin present) or as a noise suppresion ground and probably a bunch I've forgotten

Compare & Buy Step Down Transformers & Voltage Converters