Re: [CAD_CAM_EDM_DRO] Re: VFD's / Skates, Tim & JohnS.

>John,
>Somebody is pulling your plonker. A 1.5Kw Yaskawa invertor RETAILS
>for £280 and it has a fan already built in. I know I buy loads of
>these, In fact I'm an agent in the sense of getting a good discount.

=The fan was for the motor, he said as the hertzies drop down and the
spindle speeds come closer to 500rpm the motor will get hot and eventually
damage the invertor so the spindle motor needed force vented cooling if I
wanted to run it at 500 for long periods.

>You really need to do your homework though. 1.5 Kw is 2 Hp, if the
>motor on the mill is bigger than this then it's no use. You have to
>match the motor to the invertor.

=I did, the 1.5kW is the power going out to the motor which is 2HP. I didn't
make it anymore complicated than it had to be and just said "I need 1.5kW
coming out on triple phase and I'm using single phase to supply it." and I
let them work out all the bits I'm not so sure of right now. I don't
remembering being asked the voltage out but they assumed 230v, when I need
460v (The motor is rated for 415v I think, is this like how all the stuff in
the UK is rated for use on 240v but we use 230v?).

>I can offer you a 2.2kw single phase input unit, brand spanking new,
>latest model, not a last years clearout complete with programming
>panel and filters for £300

=Do you have a make for that inverter? I only just found a few places
selling them, I'm off school tommorow while the teachers show parents around
so I'll call some of these places and ask. I've felt a grinding halt to my
plans, the guy wrote back and said he'd plugged it in and the spindle motor
spins. The spindle bearings are fine he says but the motor's bearings are
noisey. Fine he says if I plan to buy a new motor otherwise they are cheap
and easy to replace. Am I about to hear number with three zeros in it? Tim,
I didn't refuse the idea of getting a VFD I just didn't see the point, no
one had actually told me what it is that makes them better. I suppose I
assumed them to be more of a novelty than something that is of use for how
much it costs. Now you've explained why it is you've all suggested one I'm
fine with spending more on one.

Thanks,
John He.



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