3 phase convertors

morning all, Ive managed to find the money to power my mill :) Is there much to choose between the 3 phase converter manufacturers?
Im thinking of transwave and boost in particular. I think Ill end up with a rotary converter, are there any things I should be aware of? The reason is that things like the power feeds are fed from a seperate dinky motor and you can use them with the spindle turned off. I think this sounds useful, and I dont want to have to rewire to add an interlock to prevent this by accident. AIUI the rotary will be ok with this, and is more likely to give me all the spindle speeds (upto 4K5) than a static one.
cheers
Dave
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seperate
sounds
this
From my experience using them over the last 25 years I would definately recommend Transwave (Power Capacitors Ltd). Not only is the product good, but the support is excellent. So far I've had one static and two rotarys from them, and the only failure ever was when I knocked the static off a shelf! And even then when I ordered a replacement voltage sensitive relay that had physically broken in the fall they initially wanted to send me one for free, until I pointed out it was my own stupidity that caused it. Certainly a rotary is more convenient in a mixed machine workshop.
AWEM
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I have no idea about the relative merits of the different suppliers. All I can say is that I've been running my mill, lathe and bench grinder off a 5hp Transwave static converter for 15 years now with complete reliability. OK you do have to fire up one of the bigger motors (mill or lathe) before you can use the little bench grinder or you'll burn it out in about a minute but that's not a major issue. I did once forget and the thing was smoking before I'd started to sharpen the tool. Fortunately it seemed to be fine again after cooling down.
You also can't switch on a bigger motor when a smaller one is already running or it'll stall. So if I want to use the lathe and mill at the same time I switch the lathe on first and then the mill. Again no real problem but not quite as user friendly as real 3 phase.
--
Dave Baker - Puma Race Engines



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Your situation is one were a rotary converter is best suited, expecially if you may add other machines in the future. I have had a Transwave rotary converter and have never had any problems at all. I would highly recomend Power Capacitors to anybody, although its worth bearing in mind that they converters are not cheap but are very well put together pieces of kit.
Stuart Pearson
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Dave
I too have nothing but praise for Power Capacitors, they were very helpful in getting a second hand static of theirs to do what I wanted.
Steve (Sheffield)
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Skip the static phase or rotary converters and go with a VFD to run th
motor on the mill. If your machine is step belt this will be significant upgrade as it will allow full variable speed control wit the twist of the knob. Also the Variable Frequency Drives (VFD) are no much more and sometimes less than a rotary phase converter.
Only caveat is if you have servo power feeds that have three phas motors in them then you will have to do something seperate for those a you can only run one motor per VFD.
The Teco Westinghouse VFDs are pretty popular.
http://www.factorymation.com/s.nl/sc.2/category.11 /.
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macona wrote:

Whilst small vfd's are cheap(ish) istr that there is a limit of about 2.2Kw on single phase 240V input ones. given the spindle motor is bigger than this its an imediate non starter, added to which Im not wanting to rewire the machine, as it could easily turn into a multi month (and pound) job, even if the original 2 speed(checkslovakian) motor can be rewired in delta, which I havent looked at.

yes, i you read the op I do have seperate power feed and suds motors. I think the 16 spindle speeds will be adequate, and its better to be making things than to be spending months making the things to make things (I have enough of those projects ongoing already...)
Dave
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Hi,
I bought a 415v 2hp inverter from Drives Direct for my Colcheste Bantam. I works a treat, is programmable, very quiet and small. Dave a DD is extremely helpful.
I was put off Transwave when I read their ebay "hatchet job" on Drive Direct. I'm not an electrical engineer and can't comment on whethe Transwave's allegations have any merit, but it certainly lost them customer. If you can't sell your products on their merits and have t resort to bad-mouthing another company then something's not right.
Anyway, plenty of other posters seem happy with Transwave, I'm happ with my DD unit
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at
Drives
to
There is history to the Drives Direct / Transwave saga. As I understand it DD started by supposedly offering Transwaves on ebay but infact knocking them and pushing their 240 to 415 v converters, that were really 415 to 415 ones that they had moddified and had not been certified. Transwave pointed this out and from then on it got messy! I am not sure if the 240 - 415v ones that DD offer even now are compliant and certified re: noise injected back into the mains.
AWEM
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i use a clark 240 -400v static converter , up to 5 hp , runs a student
a bridgeport and a small surface grinder seperately ok
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I see up to 3.75 KW 5hp VFDs available quite often.
How big of a spindle motor do you have
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