[modeleng] Re: Question about phase converters
- From: "Andrew Houston" <andrew@xxxxxxxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Fri, 3 Feb 2006 00:50:46 -0000
Steve
The other things that have to be said are that :-
Variable Frequency Drives (aka Inverters) powered by single phase 240v
should only be permanently connected to one 3-phase motor configured in
delta mode. All switching is done on the primary side.
Converters, static or otherwise can run several motors (as indicated by
other replies) and these motors can be configured as "star" windings - if
the right converter is used. Best bet is to talk to a good supplier of
converters - like Transwave to name but one.
I suppose it goes without saying, but I will anyway. A 7HP converter would
need a dedicated single phase supply in the order of 30A at 240V.
Individual VFDs of up to 1.5HP could be supplied by separate 13A outlets. A
2HP unit (1.5KW) has input surge of up to 16A and should be supplied by a
heavier outlet.
In actual fact, as larger Lathes, Mills, etc, are classed as "fixed
appliances" they shouldn't really be connected to mains using a 13A plug.
(But tell that to kitchen and central heating fitters who insist on doing
this with built-in cookers, fridges, washing machines, pumps, etc, etc.)
As an aside, a UK double socket connected to a ring-main is only meant to
supply a total of 13A MAX (NOT, repeat NOT 26A). A good make, like say MK,
will usually be ok at 20A, but this should be the exception rather than the
rule. (See IEE Wiring Regs - 16th Edition)
Andy
-----Original Message-----
From: modeleng-bounce@xxxxxxxxxxxxx [mailto:modeleng-bounce@xxxxxxxxxxxxx]
On Behalf Of Sehwuk@xxxxxxx
Sent: 02 February 2006 19:52
To: modeleng@xxxxxxxxxxxxx
Subject: [modeleng] Question about phase converters
Chaps
My first post and it's a question for any and all to answer :- Has
anybody out there got, or used, phase converters ?. I'm just on the verge
of
building the new workshop for an attempt at a 41/2" Burrell but will need
bigger
machinery than I have at the moment, which really means going to 3 phase. I
have heard good and bad things abut these bits of kit but would rather hear
from people in the know (as it were). I have definately been told that a
rotary
will be better than a solid state. ALL replies, good or bad, will be most
welcome.
Steve
Bodgers Retreat, Burwell
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