OT (slightly) : Are used 3phase converters worth anything?

[r.p.mcmurphy]

Flog em on eBay...sure to fetch a fortune.

Steve

[Kalico]

Sorry for the slightly off topic post.

I have been asked to get rid of two 3 phase converters. They have been used in a launderette to provide an 'apparent' 3 phase supply from a standard single phase supply.

When I mentioned them to a friend he cursed as he had just paid a fortune to have some installed in his motor workshop business.

Not sure the best route to find a valuation or any purchasers though.

Suggestions?

TIA

Replace 'spam' with 'org' to reply

[Malc]

I wonder how those work? Ruddy great capacitors or something, rectify and chop into 3 phase?

What I would do is to find out how much a new one is then charge a bit less than half.

-- Malc

[Andy Hall]

For an application like this, they are probably rotary convertors - i.e. a specially wound motor/generator with extra windings to generate the missing leg(s).

There are electronic ones as well, but I think it's unlikely for an application like this.

[Kalico]

Well I do know that they made a hell of a buzzing sound in operation.

God knows where i would find a price for a new one and even E-bay wouldn't find a buyer for something like that, surely?

Fact is that the launderette has just had 3 phase installed now so they are redundant.

Thanks for all the replies.

Rob

Replace 'spam' with 'org' to reply

[Andy Hall]

Yer can sell yer granny on Ebay. :-)

You could try dealers of secondhand workshop machinery.

They often have three phase machines that people would like to run on single phase.

The best thing would be to find somebody reasonably local because I guess these are heavy and transport cost would be an issue.

Here's somewhere to start

Thanks for all the replies.

[Andy Dingley]

I'll have 'em ! 8-)

There are three sorts. One works (but costs a fortune), one is rubbish, one is easily built at home. There's a good and valuable trade in all of them, through either machine tool dealers or eBay, but shipping can be a nuisance for the two heavy types.

The first is a modern VFD (variable frequency drive). This is made out of semiconductor electronics and does clever stuff like variable speed, braking and rapid reversing. Small ones are expensive, big ones are staggering. Lightweight too, in comparison to the others.

The rubbish sort are the capacitor boxes. They are moderately sized, still expensive, and require "tuning in" for the load currently being demanded. Not too bad for running a single machine that works at a constant load, but they're a nightmare for a whole workshop with varying machines being turned on and off. They're also inefficient at delivering useful power.

The best sort for most people is a rotary converter. These can be made badly from an old 3-phase motor , or made well from a big enough version of the same motor with some simple control relays. The crude ones need to be "kick started".

If you want to know more, the best resource I know of (albeit American) is at the Old Woodworking Machines site.

under "Motors and Electricity:"

[burbeck]

[Rod Hewitt]

Kalico wrote in news: [e-mail]:

Used to use one to run the naval radar at school. At least I think it was one. Know anyone who wants to run a 1950s radar station?

[Sam]

Machinemart sell them for £299 upwards, there's two on the website but I'm sure they have more in the catalogue.

As someone else suggested Ebay is most likely the easiest place to sell them, at probly far more than they are worth at that.

Sam

[Dave]

But do tell us when you're advertising them ...

Dave

[Kalico]

Well I have finally got some photos of the 3 phase converters.

There is also a beast of a step up transformer and apart from a switch, two other boxes that have no apparent identification. Any ideas?

I have put 3 photos and the specs from the name plates on to a web site. Apologies for my poor web site skills.

what do you think of them? Are they worth anything? They weigh a lot so even scrap must be something, thinking of all the copper there must be in the transformer etc.

Cheers Rob

Replace 'spam' with 'org' to reply