andy pugh schrieb: > On 11 November 2011 16:13, Peter Blodow <p.blo...@dreki.de> wrote: > > >> hereabouts, you can't even buy outlets or plugs with only 4 leads. >> > > That seems a bit strange. What do you connect the neutral to, if there > is no external star point on a motor. for example? > When you bolt an outlet to a wall you can't possibly know what the next guy will connect to it later.
> A typical VFD, for example, has nowhere to connect that extra wire. Do > you leave it dangling? Do you need to fuse it? > If the VFD (primary side) or any other device has no terminal for the neutral, just leave it. Neutral is never, never, never fused because it would not be selective and mean a danger if devices powered by other circuits are using the same neutral return lead. I killed a lot of LAN power plug adapters some years ago when the neutral wire came loose in the power distribution cabinet. In this case, devices will be connected in series between two phases, and if one is a 2 kW heater and the other a 5 W DC plug, guess which one will get the overvoltage... > (To prove they exist: > http://www.tlc-direct.co.uk/Main_Index/Plugs_and_Sockets_Industrial_Index/Plugs_and_Sockets_Ind_415v/index.html#Red_415v_16_Amp_4_Pin > ) > I believe it. In England, there exist also things like haunted castles in the moor, white ghosts at midnight, unremovable blood stains on the carpet and Maggie Thatcher :-)) Look at this: http://de.wikipedia.org/wiki/IEC_60309 for standard industrial outlets and plugs and you will know what I mean. Peter Blodow Peter Bloow ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
