DMG DMU 50 Retroftiing(?) help

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08 May 2023 16:33 #270942 by Aciera
So just out of curiosity, this would mean that your regular domestic wall socket would actually be 2-phase 220V ?

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08 May 2023 16:56 #270946 by pommen
Yes indeed. L and N is connected between two phases in the distrubution box. The wires are still brown and blue, and any switch or socket is still marked L &N though.
It kinda threw me for a loop when i first moved here from Sweden. It never crossed my mind that there were different ways of delivering household electricity. I get three phases from the supplier in to my house. In addition there is a PE pole staked in to the ground outside, and a PE cable that run in the my distrubution box. On older houses it is common to still the the PE line connected to the copper water pipe.

Just to add to the confusion, here are some more pictures.

Wires coming in to my house. 3 phase, no neutral.
 

Installation certificate in my distribution box:
 

A 3phase connector:
   
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08 May 2023 19:48 #270952 by Aciera
Interesting, thanks.
Here (Switzerland) we used to have a combined 'PEN' wire that combined earth and neutral but that was years ago. In those days there was also no neutral coming into the house just like in your installation. The PEN was 'created' by connecting it to the water pipes. So basically the 1phase was the voltage between a phase and earth.
Nowadays the neutral is brought into the house along with the three phases and the earth is usually connected to the rebar in the concrete foundation. Often the pipes are plastic now anyways.

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09 May 2023 00:49 #270976 by tommylight
Everything points out to 3x230V, no neutral.
Strange, most of Europe use the same 3x380V and neutral.
Most "low" power devices are single phase 220V, using one phase and neutral.

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09 May 2023 04:53 - 09 May 2023 04:58 #270981 by Aciera
Just found out that Belgium also still has some 3x220 installations:
www.sibelga.be/en/connections-meters/my-...ion/electrical-power

In Belgium, there are 2 voltage systems: either 230V or 400V.  In Brussels, 80% of the territory is covered with 230V. 

and I keep seeing Kosovo also listed among the countries where this type of installation exists.
Not sure if these are run as delta or star configurations, apparently sometimes one phase is grounded.
Learn something new everyday.
Last edit: 09 May 2023 04:58 by Aciera.
The following user(s) said Thank You: pommen

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09 May 2023 07:55 #271001 by tommylight
Kosovo has no more of that, i am in Kosovo, everything moved to 3x380 quite long ago.
And yes, some very old buildings do have ground and neutral tied together. Spent plenty of time removing those as ground fault protection does not work with it, and i absolutely insist on having properly working grounding and protection. Had plenty of free lunches from people saved by it.
Here everything is 4 wires, easy to see as there is plenty of wires on poles, even high voltage rails are 4 wires on very high metal poles, at 110KV.
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13 May 2023 20:01 - 14 May 2023 04:19 #271309 by pommen
The elbow grease is paying out. starting to look less and less like a rust pile :)
I also remounted the Y + Z axis that I had to take of to fit it through the garage doors.
Warning: Spoiler!



I found this drawing on the backside of the lid for the junction box for the spindle.
Warning: Spoiler!


If im not mistaken is diagram show a Y(Star) connection. It leads me to believe that the nameplate previously posted here checks out :)
Is there any risk to the spindle if connect up a 220V VFD configured as delta? Would be nice to see it spin :) I need to make up my mind if I should pursue to get the original spindle running (buying a VFD and try to get a 32 A line drawn in).

I also have the possibility to use a big transformer to get the line voltage up to 380. Although it would perhaps be more VFDs to choose from, they are quite expensive. Any tips/thoughts/ideas are very much appreciated.

/Peter
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Last edit: 14 May 2023 04:19 by pommen.

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13 May 2023 20:47 #271313 by Aciera
Running it on 220V-delta shouldn't hurt it since the voltage across the individual windings would actually be lower than when wired as 400V-Y (which is _probably_ what is was wired to before judging from the scribbles on the connector box).
My guess is that 32A might not be quite enough though.

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16 May 2023 20:38 - 17 May 2023 06:28 #271468 by gitin
Excuse me, I'm using the translator.
It is the spindle that is connected to the VFD. For 8000 rpm you need about 400 volts and 280 Hertz. If you connect only 72 volts to the transformer, the RPM will be 1,430 U/min.
Last edit: 17 May 2023 06:28 by gitin. Reason: incorrect translation

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