[modeleng] Re: FW: Question about phase converters
- From: "Andrew Houston" <andrew@xxxxxxxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Mon, 6 Feb 2006 14:47:35 -0000
Chrisc
The inverters I've bought didn't come fitted with 13A plugs. I think that
the best we can assume is that, if three people are asked to design an
installation, there will be four solutions and, as my old "Rotating
Machines" University Lecturer used to say, "All of them wrong".
I've been reading the Discussion Group on the IEE web-site about Wiring and
Regulations. It's interesting to see how many opinions there are on what
the Regs mean about certain scenarios. If "professional electricians" are
having to ask questions, what chance does Mr T. C. Mits (The competent man
in the street) have of getting it right.
Andy
-----Original Message-----
From: modeleng-bounce@xxxxxxxxxxxxx [mailto:modeleng-bounce@xxxxxxxxxxxxx]
On Behalf Of Chris Crosskey
Sent: 06 February 2006 09:25
To: modeleng@xxxxxxxxxxxxx
Subject: [modeleng] Re: FW: Question about phase converters
Also better add that the inverters aren't "permanent installations"
either, they're on 13A plugs..... Also I did the shed wiring before the
new codes came in and an electrician mate who saw it said "You don't
believe in doing things by halves do you?"..... I used to run the whole
shed off a single 13A extension lead, which it would still be legal to
do and as the total load in the shed doesn't exceed this technically it
would be safe to.... However I prefer having 100A armoured cable running
under the path to a dedicated 40A RCD in the house box and have the old
house box acting as local MCB's fior the shed.... The shed now has two
lighting circuits.....
chrisc
-----Original Message-----
From: modeleng-bounce@xxxxxxxxxxxxx
[mailto:modeleng-bounce@xxxxxxxxxxxxx] On Behalf Of Chris Crosskey
Sent: 06 February 2006 09:19
To: modeleng@xxxxxxxxxxxxx
Subject: [modeleng] Re: FW: Question about phase converters
Hi Andy,
Hmmm... Yeah I checked the manual..... From personal experience I've not
had a problem running 3/4 HP motors off 4HP inverters or 1/4HP motors
off 1HP inverters (none of them Siemens, IIRC I've got a 1HP Hitachi, a
2HP Danfoss and a 4HP LG). Also I'm not beyond doing power wiring, as
long as you make sure everything that can sensibly be earthed is earthed
and over-rate the wire by a factor of 4 (everything in my shed that can
be 60A or 100A armoured cable is) and add some common sense then you are
cooking with charcoal..... Basically my inverters run to 3-phase outlet
sockets so I can swap what is plugged into them, the 1HP and 4HP also
serve a 3-phase disconnect switch that goes to the lathe (1HP) and mill
(4HP) respectively as they are the most common loads on those units and
I picked up the switch boxes for free when a factory cleared out...
they're the big old style thing that looks like a door handle on a 1
foot square 4" deep box..... Remote controls for inverters are almost
standard these days, button for start, knob for speed, big button for
off......
Chrisc
-----Original Message-----
From: modeleng-bounce@xxxxxxxxxxxxx
[mailto:modeleng-bounce@xxxxxxxxxxxxx] On Behalf Of Andrew Houston
Sent: 03 February 2006 19:15
To: modeleng@xxxxxxxxxxxxx
Subject: [modeleng] Re: FW: Question about phase converters
Chris
Some good points about Inverters (Correctly termed Variable Frequency
Drives) vs Converters. However, they are essentially meant to be "One
Machine, One VFD"
"You don't have to have tailored loads on an inverter" - read the
Siemens
installation and commissioning instructions for their 540 series !
"add some plugs or switches to change machines over and build a mobile
control box to run it with" - sorry, I don't like the sound of that wrt
Safety, EMC, manufacturers recommendations, IEE Wiring Regulations, etc,
etc.
Andy (Chartered Electrical Engineer keeping electricity live and safe)
-----Original Message-----
From: modeleng-bounce@xxxxxxxxxxxxx
[mailto:modeleng-bounce@xxxxxxxxxxxxx]
On Behalf Of Chris Crosskey
Sent: 03 February 2006 18:28
To: modeleng@xxxxxxxxxxxxx
Subject: [modeleng] FW: Question about phase converters
Another attempt with rtf
-----Original Message-----
From: Chris Crosskey
Sent: 03 February 2006 18:22
To: 'modeleng@xxxxxxxxxxxxx'
Subject: RE: [modeleng] Question about phase converters
Hi Steve,
<Opinionated Rant>
You've been told rubbish, solid state gives you infinite control over
speed (within the limits of your motor to cope with it), all a rotary
phase converter gives you is an expensive space consuming spinning
transformer. For me I couldn't live without inverters, plus the fact
that good ones can be had on ebay for peanuts while atavistic retards
pay silly money for rotaries is just another plus in their favour
</Opinionated Rant>
I personally prefer inverters because of the speed control, you can
individual ones on a per machine basis, as long as you aren't going over
about 7.5kW (10HP) then an inverter will be a lot cheaper. Also you
don't have to have tailored loads on an inverter, so if you're only
using one machine at a time just by one big enough to cope with the
biggest thing you use and add some plugs or switches to change machines
over and build a mobile control box to run it with....
Chris Crosskey
-----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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