[Amps] What is the meaning of ACVFD ?

[Roger (sub1)]

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 at rogerhalstead.com>
> To: <amps at 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 at free.fr>
>>> To:<amps at 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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