[modeleng] Re: Oops... ignore last one, this one is RE: 3 phase

Over here in the US of A, those Inverters are pricey as hell so I made my 
own 3 phase converter from a 1-1/ 2hp 220v 3 phase motor and a rather large 
(no, I don't know the size) capacitor from my old central AC unit (4 ton 
unit).  It has worked a treat and starts the 2hp motor on my Delta lathe 
albeit a bit slowly. The 3 phase motor was brand new, but had been damaged 
in shipment due to a broken base.  I made another one for my son from a 
motor that had broken its shaft just outside the pulley and was therefore 
useless as a motor, but made a Jim dandy phase converter.

I have a good 440 inverter, but alas, I have only 220 single phase here in 
the house or I would have used it..

Jesse in the wilds of West Tennessee




----- Original Message ----- 
From: "Chris Crosskey" <chris.crosskey@xxxxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Tuesday, May 20, 2008 5:48 AM
Subject: [modeleng] Oops... ignore last one, this one is RE: 3 phase


>A lot easier to fit an appropriate inverter (if a fraction pricier). The
> capacitor network thing basically fakes a third phase by shifting the
> positive phase 120 degrees round. It is the same principle on which
> static converters work.... the problem is you frequently need to have a
> switchable set for start-up and run, and you might well need a third set
> for start, run low-load, run hi-load.... An inverter deals with all of
> this for you and it will give a modicum of speed control too, a decent
> one should give you x0.5 through to 2x or even 3x standard speeds...
>
> chrisc
>
>> -----Original Message-----
>> From: modeleng-bounce@xxxxxxxxxxxxx
> [mailto:modeleng-bounce@xxxxxxxxxxxxx]
>> On Behalf Of julianharrison7@xxxxxxxxxxxx
>> Sent: 20 May 2008 09:46
>> To: models
>> Subject: [modeleng] 3 phase
>>
>> Hi Guys,
>> Have aquired a couple of fairly old 3 phase pillar drills from a local
>> engineering works. The cosst is I have to fetch them which seems fair.
>> They are in very good condition and still being used to finish off a
> large
>> contract. Don't know the make but most of the rest of the works they
> came
>> from last year were "Senior" machines for this smaller stufff. They
> are
>> mine when job done. Rather than changing the motor I hope to keep the
> one
>> on them. I have heard it is possible to fit a capacitor to act as the
>> third phase. If this is correct can someone please tell me what
> capacitor,
>> where to connect etc
>>
>> Many thanks
>>
>> Julian.
>>
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