Recommend me a VFD

[vwmark]

Hi - having no luck finding a decent replacement (ie cheap) 2-3hp single phase motor on my mill, I am looking at replacing with 3 phase and running a VFD.

Looking back at other posts, everyone says the Chinese VFD for the money are good but never any links. Can anyone point me in the right direction?

Thanks

 

[daleyd]

I think all the Chinese versions are the same thing, like these

https://www.ebay.co.uk/itm/181737454601

If your lucky and patient you can find big brand versions (Schneider altivar, Siemens micro master, Mitsubishi etc) for the same or even less money. (They don't do anything much different but they will have better manuals and support, and are proper industrial kit - im not saying there's anything wrong with the generic Chinese ones by the way, just worth keeping an eye out if your not in a rush)

 

[Mee]

Lots of cheap Italian made motors about, it may pay you to buy a cheap piece of equipment which is scrap and salvage a decent motor.

 

[daleyd]

Out of interest what size vfd are you after? I have a 1.5kw and a 2.2 kw - I don't really need both so I could be tempted to let one of them go - both Schneider altivar, the 2.2 is a 12 series and the other is a 312 (has a few more advanced features but nothing really useful for the home workshop type application).

 

[vwmark]

Hi. I am looking at 1.5kw motor so do you need to build in any safety margin? Send me a message with price. Thanks

 

[penfold]

With brand name VFDs the plated rating is what the manual will say they can run, I've never seen one rated otherwise. Some recommend having a safety margin but I've not encountered problems with motor rating = VFD rating, although I rarely if ever operate machinery at 100%.

 

[daleyd]

Yeah, just read the specs for the 312 1.5 kw and its rated for 8A continuous and 12A transient for 60 secs, so it'll be fine on a 1.5kw motor (5.8 Amps according to rm electrical calculator). As Penfold says I've used these in an industrial capacity and they'll usually be matched to the motor size they are running, unless there is some specific requirement.

 

[steve_s]

I have got 2 VFD from http://www.invertekdrives.com/ not cheap but 2 year warranty and I have not had a problem, UK based so no problems sending fault stuff to china

 

[Wedg1e]

I have a TECO as sold by Drives Direct, it's run my Boxford and a small mill for 8 or 9 years now. Mine's a 415V-out unit.

 

[rikrobson]

http://www.ebay.co.uk/itm/Three-Pha...ilable-/192052502073?var=&hash=item7286d96380

http://www.ebay.co.uk/itm/UPDATED-1...699546?hash=item3cfcd29f5a:g:NiIAAOSw~gRVwbiX

you'll be just over £200 for this lot, but you get variable speed.

just remember it needs to be a dual voltage (star wired) motor if you want to power it of a single phase supply. the cheap Chinese vfds are only 220V not 400V.

I got one of those vfds for my lathe. the benefit is you can adjust the startup, slowdown and torque as well as controlling the speed and direction as long as you can understand the Chinglish manual, which is pretty rubbish.

a 4 pole will be half speed if your milling machine is expecting 3000rpm motor

you can gett hall sensors, magnets and tachometers from china for pennies these days, so you can make a wee box to control it. the VFD will ofcourse show the supplied frequency and have the ability to control via the supplies panel.

 

[vwmark]

Looks like going 3 phase and vfd. 3 phase 4 pole motors are cheap second hand and been offered a decent vfd on here.

I would prefer a used industrial 3 phase motor to a cheapish single phase.

 

[rikrobson]

Make sure that the mill is set to have a 4 pole motor (1500rpm) and not a 2 pole (3000rpm).
If you get it wrong, wour speeds will be 1/2 or double what you expect. You'll also need to make sure the motor is 220v (dual voltage) some are hard wired for 400v

 

[armalites]

I run my ramp with an IMO, they are not cheap but the range of settings is amazing. It is in an open barn and I have never got round to fitting a box so it's wrapped in a feed bag, it has power 24/7 and has been like that for probably 7yrs plus.