Thread: single to 3 phase vsd confusion.

Here is one (not paricularly cheap) I came across:
SAJ 4KW VSD VFD inverter 415V variable speed drive | eBay
or this Huanyang one:
http://www.ebay.com.au/itm/2-2KW-Var...item43af026b24

Hi Lather,

Could you make do with 0.9kW and 1.5kW?

Stuart

P.s. Joe I think lather only has 240V

Oh yeah, sorry, Lather. Stuart has pointed you to the cheapest option: running it on 240V 3-phase..... If you do, make sure you DON'T switch speed with the VFD runnging (only when it's off).
That works perfectly OK - at the loss of output torque (no or little reduction in speed).
Joe

Stuart,

how much would the speed be reduced when run on 1.5kw ?
if it's close to the slow speed of the original setup,it would be o.k., as the higher speeds probably won't be used.

Another option is to get a suitable S/H 3 phase motor, though will first need to know if both motors can be run using the same vsd.

edit: just noticed joe's comment that their is little loss in speed,
the amount of power loss seems a bit too much.
will set it up this way to at least get the lathe running, unfortunately can't purchase the lathe with a different motor.

A 3hp 240/415 motor can be picked up cheap second hand.

Dave

Hi Lather,
The rpm should be the same near enough*, if not you can tweak it with the VSD.
Remember the numbers I gave you were kW...... 1.2hp/2hp.

I doubt if its worth going with the 3kW VSD. If you use the motor you have wired as 415V you wont need 3kW. If you get a new 3hp motor 2.2kW will do.

This guy sells in $AU so you might save on the conversion(cant remember what it is off the top of my head) VARIABLE FREQUENCY DRIVE INVERTER VFD NEW 3HP 2.2KW 10A | eBay

Stuart

*ok I think the correct answer is it would be down a little at any given load as the slip would be increased to make the same power from less voltage(?well it sounds right, thought I'm not sure it is)......but I doubt you'll notice and as I said it just takes the press of a button on the vsd to fix if it troubles you. The VSD can be set in 0.01Hz steps, that should get you close enough

Originally Posted by lather

Placed a deposit on a lathe,
the motor nameplate details are,
2 speed 3Phase induction cage motor
type- 415V
yd112m 8-4 4.8/5A

1.5/ 2.5kw

Δ/2y
700rpm/ 1400 rpm.

is the VSD below suitable for this motor ?
UPDATED NEW VARIABLE FREQUENCY DRIVE INVERTER VFD 4HP 3KW 13A 220-250V e3 | eBay

Hi Lather,

Apologies for the slow reply, ( just back from a 3 day road trip)

Joe, Stuart and Jekyl&Hyde have already got it sussed anyway, but I'll just re-inforce what they have already said, that motor is 415 3 phase 8 pole delta (700 rpm) , and they connect the center of each of the three sides to make it a 2 stars connected in parallel to make it 4 pole 1400 rpm. (you **could** in theory actually rewire it to be 240v 3phase, 2xdelta 4 pole in parallel, but that would involve a lot of work rewiring inside the motor, I think there are better solutions)

So, in short, the motor as supplied isn't suitable for 240 volt operation at full power, you could actually run it, but at much reduced power, I wouldn't go down that path, if you can get a 4 pole motor with suitable frame dimensions, same shaft diameter and length etc.. as a drop-in replacement, that would be a workable solution.

But you might want to ask H&F whether that would have any impact on the warrantee.

Regards
Ray

PS Did you happen to see what the coolant pump power was?

Hi Ray,

I was thinking about the "rewiring the current motor " option, but couldnt make up my mind.
1. What rpm you would end up with?
2. What power you would end up with?
My guess(an a somewhat uneducted one to put it nicely) was 700rpm 1.5kW (which I figured wasnt much better than 240V on the motor as is)

Stuart

Originally Posted by Stustoys

Hi Ray,

I was thinking about the "rewiring the current motor " option, but couldnt make up my mind.
1. What rpm you would end up with?
2. What power you would end up with?
My guess(an a somewhat uneducted one to put it nicely) was 700rpm 1.5kW (which I figured wasnt much better than 240V on the motor as is)

Stuart

Hi Stuart,

It would be 4 pole ( 1400 rpm) , 2.4kw, I think.... I'd need to check)... ( still busy unloading a shaper vise...

Regards
Ray

Originally Posted by RayG

But you might want to ask H&F whether that would have any impact on the warrantee.

What warranty? We are talking H&F here, they only respond to warranty claims once threatened with the ACCC and the Trade Practices Act if peoples' experience posted here is anything to go by.

I have a use for an 8 pole 415V motor (8/4 pole would be fine) as I've got 415V 3 phase and would like to dump the 6 pole 240V single phase motor on my slotter. Mainly I want a slower stroke speed and don't want to screw with pulley changes. Lather is too far away to do any deals with though.

PDW

Forum newbie here.
I've just spent the last few evenings reading this thread about electric motor options, phases, 415/240v conversions and VSD/VFDs (that's normal though, right??)
I've learned quite a bit about these subjects and also, quite a bit about MWF.
The most important thing I've learned is that I've definitely made the right decision to bite the bullet early, and go for 3 phase power in the shed that I'm building.
It's a lot of money to upgrade the house supply and to run 6mm, 5-core cable to the shed (and through the slab to the various places I'll need power) but once it's done, I think I'll forget the cash and just be happy.
Many thanks to all the contributors.
Freddie.

This is a relatively old thread - considerable water has passed under bridges since then.

Maybe have a read of the first two threads in this forum https://www.woodworkforums.com/f271
You will need to register to see the photos.

Originally Posted by BobL

This is a relatively old thread - considerable water has passed under bridges since then.

True. But he's still correct - if you can afford it and can get it, genuine 3 phase 415V power beats the hell out of relying on VFD's to do it any day of the week.

You can still run them on 415V or less of course, but you don't *have* to, and multi-speed motors like the 2 speed on my Arboga drill or the 3 speed in my Kearns S type HBM just simply work as intended. Not to mention running a decent sized air compressor.

I even ran 6mm 3 phase cable down to my dam 120m from the workshop while I had a trench open. I did it 15 years ago and only used it for the first time about 2 weeks back when I decided I was bored and needed to start another 3 long-term projects.

I've gotten a few too many finished and can't spend as much time sailing my big toy ATM.

PDW