Inverters

A friend has purchased a machine that has a RS inverter with a 3 phase input. He wants to run this machine from a normal single phase supply. He has purchased a new inverter from RS with the same output characteristics but designed for single phase input and this has been installed on the machine. He needs someone familiar with inverters to set the new inverter up and program it correctly. Does anyone one know of an electrician in the Slough, Berkshire area who could do this?

Thanks in advance for any suggestions.

Mike

I'm a little surprised that he needs to swap inverters. A large number of the usual home workshop-size inverters (up to 3HP, say) will typically have connections for three-phase input, but are also suitable for single-phase. You just connect to two of the three input terminals.

However, you have not mentioned voltages. Three-phase input often implies 415V where "normal single phase supply" implies 240V. There are a few inverters around that will take 240V single-phase in and supply 415V three-phase output but at a quick glance I'm not sure that RS supply them - theirs are all same voltage in and out.

Can you clarify?

I agree with Nelabs comments.

Also RS don't make inverters, they rebadge them. Details of the model numbers would help. It might be a simple matter of copyingthe settings across.
A "electrician" is unlikely to help with this, he needs an automation engineer.

Details of the machine to be run from the inverter (particularly a photo of the nameplate on its motor) would also help people here to give best advice.

Be careful, the 3ph input ones have much smaller smoothing caps on the mains DC side, because it is 3ph. It is very unlikely one would work off of just a sp input. In my experience if it is 3ph input then it outputs 400V 3ph, so even a transformer boost from 240 to 400 won't work.

On the other hand the larger inverters have terminals for extra smoothing caps, so could add as many as you want.

This is high power electrics, only meddle if you understand it!

Thanks for all the comments.

The new single phase input RS inverter has the same output characteristics as the three phase version that it replaced.

The motor does not have a name plate.

I do not want to meddle with inverter because I do not understand them in any detail and that is why I am looking for someone competent in this area to check the installation and program it.

Mike

There are many VFD's on the market and in the industrial sector most are either 3ph in and 3ph out or 1ph in 3 ph.

One thing you might try Mike is to hook up the old VFD putting the 230V supply across two of the 3Ph input terminals - it is quite likely that the control circuitry just runs off 1 phase, you may have to swap them until you find the right combo. The purpose is to see if you can interrogate the programming to see what parameters are set as this will greatly aid setting up the new unit. Yes it will generate a loss of phase error but you are not trying to run a motor just see the menus.

When looking for an electrician you need to find one who has industrial automation experience, domestic installers are unlikely to have the skills you need.

Tony

This probably won’t help much, but … for those eager to assist Mike, it’s worth noting that the RS list of ‘own brand’ inverters with 3-phase input is quite short:

The choice of this particular one was just my wild guess: **LINK**

https://uk.rs-online.com/web/p/inverter-drives/1748217

… as usual with RS, adequate documentation is available from the product page.

MichaelG.

That inverter linked to is made by Teco,, from their L510 series….

From my experience, relatively straightforward in programming.