In Europe, I need to create a four wire 230V line from a three wire 230V.

[KH6VP]

Hi all,

In Europe we use 230V three wire [phase and neutral and ground].
In the US we use four wire 230V [phase 1, phase 2, neutral, ground] where it is 230V between phase1 and phase2 and 115V between either phase and neutral].

I need to create a standard 230V four wire line from a standard three wire 230V line [plus ground]. I want to use it for some linear amplifiers I brought over from the US, that require four wire 230V.

Has anyone done this successfully?

Peter

[KD1SH]

   I would think that you'd need a transformer, since U.S style 230v (or 240v) implies phase 1 and phase 2 being 180 degrees out, and given only a single phase coming in, only a center tapped transformer can create that condition.
   It always drove me crazy that here in the U.S we customarily refer to our 240v service as "single phase," even though there are two separate and distinct phases, 180 degree out. Your European 230v service is truly "single phase."
   In the U.S, we actually have two code-approved methods of delivering 240v: by using three wires, or four. In the three wire circuit, we have the two phases, L1 and L2, and a ground, whereas in the four wire circuit we have L1, L2, neutral, and ground. Both will essentially perform the same function, but the distinction is regulatory and safety. If the appliance you're connecting to will apply the load between L1 and L2 only—in other words, it will use 240v only and never 120v between either phase and ground—the three wire connection is fine. The ground wire in that case is a safety ground only; it will never be used as a return path for current.
   If your appliance needs to take power both between phases and from either phase to neutral—and I'm assuming your amplifiers are in that category—the code requires four wires, with the return current for any 120v load being taken by the neutral wire, never through the ground wire. It's all about safety—if you use only three wires on an appliance that uses both 240v and 120v, and the ground (now your only return path) opens up, the chassis goes hot.

[K8DI]

It may be easier and will likely be cheaper to modify stuff to work there. Consider running the 240 stuff off the 240 line, and a step down transformer for the 120 stuff, and some rewiring to separate the 120 from the 240. I'm going to bet that of your 240v stuff that does have 120v bits, none of them are particularly high current, meaning said step-down would not have to be large. You will want to avoid autotransformers in this application.

Regarding the "180 out of phase"...they're not, they are of opposite polarity. Polarity vs. phase is an audio argument us audio guys have been having since the first balanced circuit -- and that's what the US 120/240v system is -- balanced, two lines of opposite polarity around a center, grounded neutral.

Be aware that running US spec stuff in Europe also means 50Hz vs 60Hz.  Some motor types will run slow and have reduced torque, running slower still, and undersized transformers will run hot as they saturate, and devices with borderline filter capacitance will hum more.

Ed

[KD1SH]

  Yes, anything running off 120v is most certainly low current—fans and blowers, maybe some transformers to supply low voltage for relays and control circuitry. Maybe, but probably not likely, a filament transformer. It wouldn't be good practice to intentionally create a significant unbalance on a 240v line.

  Good point about the 50hz—hadn't thought about that.

  Indeed, the U.S distribution system is "balanced," and L1 and L2 are "opposite," but opposite in what? Phase, maybe? But I digress, and certainly don't want to hijack the thread. It's an interesting semantic point, though, and worthy of friendly debate. I'll surrender, however, on the grounds that utility workers and electricians here in America have decided to call 240v circuits "single phase," so it's a done deal.

It may be easier and will likely be cheaper to modify stuff to work there. Consider running the 240 stuff off the 240 line, and a step down transformer for the 120 stuff, and some rewiring to separate the 120 from the 240. I'm going to bet that of your 240v stuff that does have 120v bits, none of them are particularly high current, meaning said step-down would not have to be large. You will want to avoid autotransformers in this application.

Regarding the "180 out of phase"...they're not, they are of opposite polarity. Polarity vs. phase is an audio argument us audio guys have been having since the first balanced circuit -- and that's what the US 120/240v system is -- balanced, two lines of opposite polarity around a center, grounded neutral.

Be aware that running US spec stuff in Europe also means 50Hz vs 60Hz.  Some motor types will run slow and have reduced torque, running slower still, and undersized transformers will run hot as they saturate, and devices with borderline filter capacitance will hum more.

Ed

[KD6VXI]

As someone else pointed out at 50 hz the transformers will be less efficient.  Also the cooling fans or blowers will run slower.

Easy fix for power.  Run the 117 volt stuff off the center tap on the plate xformer.  Plate xformer will be two 120v windings in series.   Between the neutral lead and the center tap you have 120v..  Rarely is there enough current being drawn by a blower and relays, etc to cause much of an imbalance.

They make 120v/240v isolation xformers too.


--Shane
WP2ASS / ex KD6VXI

[WQ9E]

What Shane suggested was commonly done with amps, Heathkit put the fan across 1/2 the primary of the power transformer in their SB-200 and SB-220 amps and Drake did the same with the blower in their L-4B except it was across 1/2 the primary of the filament transformer.

Most amps would have power transformers suitable for 50/60 hz service but that might not be the case with low priced units designed only for the U.S. market.  I haven't kept up with EU power ratings for amateur radio but that is something else to check.  I recall at one time, Germany had a power limit based upon limiting the maximum rated plate dissipation tubes that could be used in the final.  I suspect during that time there were some anodes glowing brighter than filamentary cathodes during contests 🤣

Rodger WQ9E

[KH6VP]

Finally, I created a unit using a 2KW 230V isolation transformer (I had) that has a 230V CT secondary thus creating a 3 wire 230V service. I used a special NEMA socket on the output (the one with two flat blades at right angles) so there would be no confusion. I am changing the plugs on my units to compatible NEMA plugs.

Tried it and it works well! Thanks for the suggestions.

[n8fvj]

There is no neutral wire in Europe.

[KD6VXI]

There is no neutral wire in Europe.

This is incorrect.

There isn't split phase feed in Europe.   It is 3 phase.  There is still a neutral conductor.

This doesn't mean anything in regards to the OP, however.  And his question is answered and solved.

--Shane
WP2ASS / ex KD6VXI

[KD1SH]

https://commons.wikimedia.org/wiki/File:European_plug_and_sockets,_UE_standard,_EU_plug_and_socket_wiring_diagram,_schuko,_french_socket,_cee_7-7.jpg

There is no neutral wire in Europe.