Re: What kind of motor should I use?

--- In CAD_CAM_EDM_DRO@y..., JanRwl@A... wrote:

> In a message dated 03-Feb-02 15:42:15 Central Standard Time,
> datac@l... (Chris) writes:

Hi, I'm fairly recently over from the UK, while I was there I had a
hydraulic copy mill that used a small Bridgeport head. It was a PITA
to change speed, so I ran it from a variable frequency controller.
This unit, single phase i/p 3 phase o/p, was adjustable from 0 to
240Hz, in the UK which uses 50Hz, this meant that the motor could run
up to almost 5x faster than faceplate RPM. In practice I never
operated it at the higher speeds, but I did run it up to see how much
vibration was produced.. not very much.

How practical it is to run say a 3600 RPM motor at 14,400 RPM I don't
know, and how long the bearings would last is another question.

The UK units were fairly reasonaly priced, a .75kw (1HP) unit was GBP
284 (US$300) and a 1.5kw (2HP) was GBP 284 (US$450) 1999 prices.

I'm still finding my way around in the US so I don't know what's
available over here.

>
>
> > You had a LOUD Perske ??<< HORRIBLY-so! (a BIG 'un: 3.5 HP)
>
> > The two (note correct use of word [!!!] ) I stood behind were

very quiet. <<

> > There are two "groups" of Perske spindle-
> > motors, one with an external fan (sirens!) and TENV kind. The

ones YOU

> stood behind: Fans?
>
> As you pointed out, they > get expensive because the Inverter

costs so

> > much more than the spindle.
> > We could use a few newcomers *to the affordable spindle field

*too! <<

> > Scho' nuff! Listen-UP, 'Merikun mfgrs!!!
>
> > Some of the German stuff does not seem to have any resellers over

here.<<

> Yeah, Perske has a reseller in NJ. Been 15 years, so I'd have to

look in

> file to see who/where.
>
> I wonder what kind of $$$$ they can buy stuff like that for over

there?<<

> Even HIGHER, I think, due to the German VAT and Lohnsteuer.
>>
> Maybe one of the

European Group

> members > could set up someone in the states *to market spindles at

a lesser

> > rate.....<< Lossa luck!
>
> Did I read somewhere in this group that "regular 3-phase tool-

motors" can be

> used at higher frequencies [with care] to produce high-RPM

spindles? Seems

> dangerous and dubious. Can an expert "in here" on that comment?

The ONLY

> experience I have with HF motors is with a 95 watt "aircraft

instrument

> motor" running on 115 VAC 400 Hz. (which I get from a self-

designed/cobbled

> stationary inverter that "simulates" sine-wave 400 Hz/115 VAC).

That is for

> a PCB drill, and it works just fine (12,000 RPM, not 24,000!!!)

But, took

> some fancy machining to install a collet and larger ABEC-7 spindle-

bearing in

> place of original "plain shaft", etc.)
>
> P.S: The Perske stuff DID seem like well-did hardware, but even

still, the

> pricing was what I'd guess would be half- to as-much-again as any

American

> mfgr. would want for "same thing". Comments? American HF spindle

makers?

>
> Sincere ignernce, Jan Rowland, old troll
>
>
>
>
> [Non-text portions of this message have been removed]