240v to 110v step-down convertor

Voodu Child

I need a step down transformer to power some electrical equipment from the US. The combined power consumption is probably about 300W, so ive been looking at domestic 500W and 800W units, along the lines of this:


But it occured to me that all the gear on construction sites is 110v, and we use big (and small) heavy duty units like this:


A quick search on ebay turned up one like that, that was actually cheaper than the domestic ones, and yet rated to 3.3KVa.

Is there any reason why I couldnt use one of those, and just wire my equipment up with standard site 16A plugs?:

The cables off my equipment are standard kettle leads, i could buy new ones for a couple of euros and wire on the 16A plugs.

I dont really need the extra capacity, but if theyre sturdier and just as cheap, is there any reason why not to?

Thomas_S_Hunterson

You probably shouldn't run low consumption appliances like that without fitting some sort of fuse.

I'm not sure how those site plugs work(i.e. if they're fused or not), but it would be wise to have a fuse in there somewhere because your appliances shouldn't be drawing more than about 3A altogether.

But other than that, no I don't see why not

Voodu Child

Heres what I know:

The appliances are normally powered with IEC (kettle type) leads, which in the US are unfused anyway (afaik).

The two appliances are fitted as standard with 6A and 1A slow-blow fuses respectively, right at the power input. (the 6A sounds high, i know, but the power consumption is listed as 1A at 117V in the manual, i believe the fuse is rated so high to allow for power spikes)

The step down transformers just plug into a domestic power supply, and as such have a 13amp plug on the input end.

The industrial plugs in question are 16Amp 110v plugs. They are unfused AFAIK

So....does that sound decent enough?

themole

What exactly are you trying to power?

The site transformer may be cheaper because is may not regulate the power as accurately as the other bench transformers.

When using power tools and the like the quality of the power is not that important, but depending on what you are powering the device could be damaged by "dirty" power.

bushy...

They are both probably just transformers anyway ,so the site ones would have more copper and iron mass . You can get powerstrips with US style sockets and a fuse in them too.

Voodu Child

themole wrote:

The site transformer may be cheaper because is may not regulate the power as accurately as the other bench transformers.

When using power tools and the like the quality of the power is not that important, but depending on what you are powering the device could be damaged by "dirty" power.

Yeah, thats the kind of info i was wondering about, a technical reason not to use the industrial one..

I reckon I might just loosen up the purse strings a little and shell out on a good, heavy duty bench transformer.

Cheers lads

themole

one thing i have noticed from those big yellow ones is that they have a fairly strong magnetic field. This will show up if it is beside a TV for example.

Michael Collins

themole wrote:

When using power tools and the like the quality of the power is not that important, but depending on what you are powering the device could be damaged by "dirty" power.

Yes, this could definately be the case. What you need to know is it a true sine-wave transformer? For stuff that run on motors (such as most power tools) it generally doesn't have to be a very "clean" sine wave as the inductive element of the coil acts to smooth it out. Other applicances such as computers or other sensitive electronics might not work or quite possibly be damaged by using one of these...