Transformer vs VFD/Inverter

[Wade BeattyParticipant @wadebeatty78296]

My 380V lathe shares an 220X415V inverter with my 400V mill. The are not operated at the same time… ever.

I see that there are 220 X 400V 3 phase transformers for sale on the local web.

Is there any reason not to use a transformer for 400V 3 phase in my shop? There have been many threads on this site regarding inverters but few on transformers for step up.

I attach photos of a transformer nameplate and the lathe motor nameplate.

Thanks in advance

[noel shelleyParticipant @noelshelley55608]

It requires 3Ph input ! I take it you only have single phase hence the use of an inverter so, no help . A transwave converter uses a step up transformer and capacitors to give a type of 3Ph. This is an isolating transformer, step up, or down.   Noel

[Wade BeattyParticipant @wadebeatty78296]

Yes, I have 3 phase 220 in my workshop.

[Andrew TinsleyParticipant @andrewtinsley63637]

Somewhat puzzled by your statement that you have a 3 phase 220 Volt supply to your workshop. Are you in the UK or maybe the US? The standard 3 phase supply in the UK is the usual 415 volt 3 phase standard. I believe that 220 volts is standard in the US for a 3 phase supply.

If you are UK based, I would be fascinated to know who is supplying you with a 220 Volt 3 phase supply.

Andrew.

[Wade BeattyParticipant @wadebeatty78296]

I am in Norway, about the transformer?

[Julie AnnParticipant @julieann]

Is that 220V live to neutral or phase to phase?

Julie

[Speedy Builder5Participant @speedybuilder5]

I have 3 phase and neutral thus 3 indépendant 240 volt supplies

[Wade BeattyParticipant @wadebeatty78296]

phase to phase, just normal 3 phase

[BazyleParticipant @bazyle]

It seems this is normal in Norway while it would never happen in the UK so transformers like this are going to exist specifically for running imported machines. I don’t understand if the current and hence power is per phase or overall. Any help from the manufacturer’s website.
3 phase input inverters are not that expensive just not used by UK amateurs because we don’t often have 3 phase in domestic properties.

Could you put the Norwegian flag as your avatar like I have the Devon flag to give people an idea that you are not UK based.

[Robert Atkinson 2Participant @robertatkinson2]

If you have 3 230V to neutral phases you have a 400V 3 phase supply. Your motor should run off this directly.  The Phase to phase voltage is 1.73 (square root of number of phases, 3 in this case).
The transformer is Star to Delta so used to run a 230V delta motor from your 400V star supply  or provide 3 independent 230V isolated supplies.

Robert.

[duncan webster 1Participant @duncanwebster1]

But he’s got 230v phase to phase, which according to interweb is an option in Norway. I suspect 230v 3 phase in to 3 phase 415 out inverters are a bit rare.

[Wade BeattyParticipant @wadebeatty78296]

Lets forget my question please, this was about a transformer, not an inverter. Thanks for the replies.

220, phase to phase Robert

[Thor 🇳🇴Participant @thor]

Most new consumer mains electric installations in Norway uses the TN system that gives 400V phase to phase and 230V phase to Neutral. Older mains systems were used several places, including where I live which has 230V phase to phase.

@Wade, if you decide to buy the transformer to get 400V 3-phase let us know if it works.

Thor

[Wade BeattyParticipant @wadebeatty78296]

Thanks Thor, we have an older property on Karmøy with 220V phase to phase

[Andrew TinsleyParticipant @andrewtinsley63637]

Having understood what you have. Why on earth do you think that the 3 phase transformers would not work to give you a 415 volt 3 phase output. It is a no brainer.

Andrew.

[Mark RandParticipant @markrand96270]

Yes, the transformer will do the job perfectly. With sufficient capacity it’ll run the lathe and the mill at the same time. (If you can run between the machines fast enough 😀 )

[Wade BeattyParticipant @wadebeatty78296]

Sorry Andrew, I usually receive excellent help here to my questions, this thread has obviosly rubbed a few people the wrong way. My no-brainer will be to use another forum.

Bye oo

[Andrew SkinnerParticipant @andrewskinner94774]

Oh dear… Well a bit late, but I’d say in answer to the question, “is there any reason not to use a transformer…”:

Both the lathe and mill would surely benefit from being hardwired to their own VFD. So I’d spend my money on another VFD and some pots/switches, to take advantage of all the features of VFDs – soft start, braking, reverse, speed control, low speed torque boost…

My lathe and mills are all run on VFDs, and even if I could get real three phase in, I wouldn’t change that.

Even better, if your motors are easily configurable, set them up to run on 230V and buy two standard AT1 VFDs. As I understand it, the step-up VFDs like you have are often normal ones modified with a voltage doubler at the input, so perhaps pushing the design a bit.

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