On 7/2/2011 9:00 PM, Carl wrote:
> A 10 HP or higher 3 phase motor and a couple of surplus utility
> company phasing capacitors is the working mans way to tackle it.
>
> Since I dont run that much big 3 phase tools and only one at a time, a
> 7.5 HP "idler" motor has been used for over 20 years, it draws
> negligible power to run. The motor cost $50 and the caps were $5 each.
> There is a surplus of 3 phase motors these days and the cost would
> likely be scrap value if you shop around.
You read my mind. <:-))
There are quite a few tool room lathes and mills available at very
reasonable prices lately. They are usually a *tad* large for hobbyists
and the market for machine shops has pretty well dried up as that's
where most are coming from. I've been looking at a Bridgeport floor
mill with digital readout on all three axises as well as power feed on
all three. I don't remember if it's a 42 or 48" bed. Weight is *about*
2000#. All 3 phase. I think the main motor is 3 or 4 HP...Might be 5,
but I don't think it's that large. I'm also looking at a tool room
lathe with a 7 HP 3 phase motor (60" bed) weight is about 5,000# (give
or take)
I have to admit I like the thought of a CNC, but virtually all are of
the older style and not an advantage for a one or two off project. The
new ones will take the input from my 3-D drafting program and you just
have to put in the tool sizes. I'm not at all familiar with the older
CNC setups. New ones are *expensive*
73
Roger (K8RI)
>
> Carl
> KM1H
>
>
>
> ----- Original Message ----- From: "Roger (sub1)"
> <sub1@rogerhalstead.com>
> To: <amps@contesting.com>
> Sent: Saturday, July 02, 2011 6:33 PM
> Subject: Re: [Amps] What is the meaning of ACVFD ?
>
>
>> On 7/2/2011 3:17 PM, Paul Kraemer wrote:
>>> AC Variable Frequency Drive
>>> An electronic motor control that rectifies incoming line voltage
>>> (single or
>>> 3 phase) to provide a dc buss voltage (approximately 350vdc for a
>>> 230vac
>>> drive) which is supplied to a "six pack" array of power devices
>>> (transistors
>>> or fets) which is controlled by microprocessor to synthesize a pwm 3
>>> phase
>>> output to a motor.
>>
>> I've been told not depend on the solid state 3 phase converters to run
>> much of a motor. When you get up to a lathe or mill a rotary converter
>> works much better and of course costs many times more. <sigh> For a 7
>> HP lathe it takes a 15 to 20 HP rotary converter. (run 2 to 3 times the
>> rating of the load) Too bad too as the solid state converter is a few
>> hundred dollars while the rotary converter is $2,000 or more.
>>
>> 73
>>
>> Roger (K8RI)
>>> Paul K0UYA
>>> ----- Original Message -----
>>> From:<pdussertvidalet@free.fr>
>>> To:<amps@contesting.com>
>>> Sent: Friday, July 01, 2011 11:44 PM
>>> Subject: [Amps] What is the meaning of ACVFD ?
>>>
>>>
>>>>
>>>> What is the meaning of the acronym ACVFD ? Message 1 , vol 103 ,
>>>> from Paul
>>>> Kouya
>>>> .
>>>> How can I connect a one phase transformer , 230 volts , on a three
>>>> phases
>>>> main
>>>> using the three phases to split the power between them ? 73 from
>>>> Pierre /
>>>> F8GY .
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>>
>>
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>
>
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