Hello, I'm after a simple and compact diagram to convert 230VAC to 110VAC able to handle 3 amps max.
I need it as small as physically possible so it can fit into a battery charger.
I have purchased a Milwaukee 110 volt charger unit and want to run it from 230VAC mains.
I have a step down transformer but its too heavy and bulky to carry around with me, so I would love to be able to find an electronic way of reducing the voltage.

Any help greatly appreciated.
I'm not an electronic buff, so please keep it simple.

I'm in Adelaide South Australia, so parts relevant to this country would be ideal.

Many Thanks
Paul

 

It's a step down transformer, end of story!.

By using an auto-transformer it will be as cheap, small, and light as possible, and they are freely available for this exact purpose - often with in-built American 2 pin sockets!.

There's really no other sensible way - but what is it for charging?, 330W is a hell of a big charger! - are you sure of the requirements?.

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Well, its for a lithium ion battery charger which states it draws a maximum of 3 amps.

What about a voltage divider circuit?

 

Hi Paul,

Isn't there a possibility to connect your charger to one phase
and ground, you'll get 130 volts if you can.
Otherwise you could let your wife carry the transformer.

on1aag.

 

Don't know where YOU are, as you don't have your location filled in - but this wouldn't work in Europe, or anywhere with European/British mains systems.

BIG bang, don't attempt it!.

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Do you have a meter with AC current ranges so you can measure it?, and how large is the battery - taking 330W would probably be larger than a car battery?.

No, like I said, an auto-transformer is the cheapest, lightest and most sensible method. A voltage divider 'would' be possible, but would cost more, be MUCH larger, and run absolutely red hot - and probably be a fire hazard.

Can you not source the corrct charger for your country?.

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on1aag,
That's assuming he live in the US.

We don't have a split phase system, here in Europe we use a three phase system with a star (Y in US English) connection. This means you get 0 to 230V not 115V-0-115V so your suggestion won't work.

An autotransformer is the only sensible way to go, they're also more light and efficient than standard transformers.

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If you've got a 3 x 230 volt system you can always connect a load
between one of the phases and the neutral conductor, you"ll get 130 volts.
The same applies to a 3 x 380 volt system, the 230 volt relays always operate between one of the phases and the neutral conductor.
They never use a transformer when the neutral conductor is available.
But I don't know what the electrical system looks like down under,
it's probably upside down too.

As for my location, you can find it in the international callbook, you
should have known that Nigel.

on1aag.

 

That's not allways true.

There is allways one grounded wire at the distribution transformer, but in 3 x 220 V systems it may not be the star's centre. In fact, if the transformer's secondary is wired in a Delta (or "D" or triangle) configuration there is no star centre at all.

In that case one of the three wires is grounded, and you may have one "neutral" and one "live" (220 V between them) or two "lives" (also with 220 V between them).

We still have some old 3 x 220 V systems here, but allmost all the electrical system is 3 x 380 / 220 V - That is 380 V three phase, with neutral, 220 V between any phase and the neutral.

And (for you in the USA) its 50 Hz here

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Like I said before, you are completely 100% WRONG - the European system is three phase 230V with each phase 120 degrees apart, this means there's 230V between each live and neutral, and 440V beween lives. There's no way you can get 130V off of it (without a transformer).

As a moderator I could have checked your IP address as well - but why should I?, it makes sense to have your location filled in - in this case you posted a dangerous suggestion, giving the impression it would work. If your location was filled in it would give the OP some idea of the validity of your post.

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In Europe, we get 230V between a phase and neutral. Between two phases we get 415V.

I think you're thinking that we get 230V on two phase ? We don't.

Edit: Nigel beat me to it.

 

Why are we supposed to know where on1aag is posting from? And if it somehow gives your location, why do you object to having it in your profile?

I see your name in a lot of Google hits, but no location.

 

Even worse he lives in a location where he gets three phase 230V mains, just as the OP does - so HE doesn't even get 130V between live and neutral, he gets 230V as the OP does. Makes his post even worse!.

A quick google soon finds callsign allocations at http://www.arrl.org/awards/dxcc/itucalls.html

So he's from Hercule Poirot country!.

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google claims this information, which concurs with Nigels' findings.

on1aag
Location: Antwerp, Belgium.

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That's not always true, some systems aren't earthed at all.

Sometimes, the neutral point is made by a zigag transformer rather than at the the main transformer; this done when a neutral connection is required with the secondary of the transformer is connected in delta.

Two phase isn't a 180 degrees (that's split phase), two phase is 90 degrees. Lol I've just had this argument with someone at work and he refused to accept it,

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