VFD Suppliers

[wbleeker]

I am embarking on an AL54B CNC conversion, I have been looking for a VFD to drive a 1.5kw 3 phase motor.
I got a quote from Drives Direct for a Teco Cv @ 257UKP incl Vat plus freight, I emailed him to tell him my address and mentioned that he didn't have to charge VAT, despite another email,no reply?
So I thought I would try Teco Australia they want 683 AUD!
So what I am looking for is someone who supplies these at the right price who will return an email!
Any suggestions?
Will

[Dave J]

A lot of guys here have these one's below and I am just about to buy a couple.
VARIABLE FREQUENCY DRIVE INVERTER VFD NEW 2HP 1.5KW g | eBay (http://www.ebay.com.au/itm/VARIABLE-FREQUENCY-DRIVE-INVERTER-VFD-NEW-2HP-1-5KW-g-/390254514549?pt=BI_Electrical_Equipment_Tools&hash=item5adcfb5175)

Dave

[Jekyll and Hyde]

Heh - Drives Direct still not replying to emails despite being in their new factory - they must do themselves out of so many sales....


A lot of guys here have these one's below and I am just about to buy a couple.
VARIABLE FREQUENCY DRIVE INVERTER VFD NEW 2HP 1.5KW g | eBay (http://www.ebay.com.au/itm/VARIABLE-FREQUENCY-DRIVE-INVERTER-VFD-NEW-2HP-1-5KW-g-/390254514549?pt=BI_Electrical_Equipment_Tools&hash=item5adcfb5175)

Dave

I've been running the 3hp version of that on my Bridgeport clone, no issue with it so far. Well, okay, maybe one - the fact that they're now HALF THE PRICE they were when I bought mine.

Seriously, $140 delivered for a 3hp VFD is ridiculously cheap, mine cost about $230 not even 12 months ago!

You do need a motor that can be wired 240v delta though...

[Dave J]

The 2 I am getting are going to be the 3hp one's as Brian is sending me up a 3hp motor next week.
The other drive can sit there until I get a couple of motors for the mill and use the one between the 2 motors on it. I may as well get it while it's cheap.

I looked 12 months ago and was going to buy one in case they went up, lucky I didn't because as you said they have come down in price a lot.

Dave

[neksmerj]

J&H.

You ask if the motor has to configurable as delta. The answer is yes, unless.....more later.

Ordinarily, a VSD can only output the same voltage as the input. For example, if you have 240V single phase in the shed, then the normal VFD can only output 240V 3-phase. If your supply is 415V, the VSD will output 415V.

If your motor is hard wired as 415V delta, running it from a 240V output VFD, will run but at reduced power/speed etc. Not recommended.

The exception to this a VFD supplied by Drives Direct. They have a standard Teco unit modified to run on 240V 1-phase input with a 415V 3-phase output. This VFD is not available from Teco, and I don't think Teco sanction the mods, or warranty the mods. However it is available.

I have a 1HP unit from Drives Direct, and Stustoys has a 3HP unit. I haven't hooked mine up yet, ST has.

As far as I know, no-one else has a similar unit, and I had to pay around $500 for mine including a remote hand held pendant. The pendant has FWD, STOP, REV and SPEED.

PS. I managed to negotiate a price from Drives Direct, less the 20% VAT. Took some doing, but perseverance paid off.

Ken

[RayG]

Hi All,

I've recently been playing with those Huanyang drives, and i've no complaints, but, don't take that as an unreserved recommendation however, I'm still a little cautious, simply because they are so cheap..

They have a good range of input/output for different types of control, I would say they are much more configurable than the Teco.

They aren't as good as the Danfoss or any other drive that does vector control, by that I mean the more advanced drives that sense the motor feedback and adjust the output to maintain the set frequency. The net result of this is that you get near to full torque at low frequency (low rpm's) The sceptics will still quote HP=torque*rpm/5252, and that's true unless there is an overriding control system like vector control.

Here's a tip for buying from that ebay seller, select sort items by "price+postage" then go to the store and enter the search for the hp you want, what you will find is that the price AND postage varies all over the place, often there is a big difference between the exact same items .. I just checked, and for a 2hp drive, the dearest price was 124+95=219, and the cheapest was 87+34=121.... that's a little more than half the price of the dearest listing.

eBay Australia: Buy new & used fashion, electronics & home d (http://stores.ebay.com.au/love-happyshopping/_i.html?rt=nc&_nkw=2hp&_sid=749694567&_trksid=p4634.c0.m14.l1581&_pgn=1)

Regards
Ray

PS Gotta love that name "love-happyshopping"

[Stustoys]

PS Gotta love that name "love-happyshopping"
Yeah I had a laugh at that as well.
I've been looking his VSD prices and thinking what a waste of time my box to switch the VSD between machines is lol. I'll in interested in how you get on with them.

Call me a sceptic but I am willing to be converted lol. Are you saying a 1440rpm motor can make 400% torque at 350rpm? A simply yes or no will do as I doubt I will fully understand the long version of the answer.

The only thing to watch on ebay when you get prices like that is that paypal take a nice little cut for currency conversions...... although its nothing like 80% lol

Stuart

[RayG]

Hi Stuart,

I don't think there is a short answer, but V/F drives are just that, you have a voltage versus frequency curve (usually a straight line) offset from zero by some amount (sometiomes called torque boost). So as you go slower, the voltage and frequency both decrease, and with lower voltage you get lower current and hence lower magnetic flux, torque depends on the magnetic flux. so the torque drops away at low speeds.. Not a problem for machines that run mostly at full speed. But could be a problem for lathes and mills, if you are expecting the same torque you would get from a gearbox reduction of the same amount. You also get a reduction in torque when you go higher than the rated Hz..

Vector drives, are totally different, they sense the motor rpm, with more complicated algorithms and circuitry, and boost the voltage as needed (even at zero rpm) to maintain the current and hence flux to get higher torque at low speeds than you get with V/F drives.

These Huanyang drives are V/F drives. What that means in practice, is you have to still select appropriate gearing for the job, or at least somewhere near it. I guess depending on how hard you are driving it ( the mill or the lathe)

Vector drives are more expensive, but, sometimes you get what you pay for.

That said, I now have 7 of these Huanyang drives, linisher, grinder, pumps and so on, but I have a Danfoss (Vector drive) on the lathe.

Regards
Ray

PS... The short answer was "maybe"
PPS...

Are you saying a 1440rpm motor can make 400% torque at 350rpm?
Ok, another answer is yes, of course,..... (pause for effect)... if you have a 4:1 reduction gear box.

[Dave J]

Paypal charge 2% for currency exchange. It's hits when you start getting up to $500 or more just to convert money over. I also notice their exchange rate is lower than whats going, you can opt out and have your bank do it instead but I am not sure if that would be better or not. At least with Paypal it is written there in black and white and you know how much it costs.

Dave

[wbleeker]

Some good info here, thanks! While were are talking about VFD's Where is the best place to get a motor I am looking for a 1.5kw.
Will

[eskimo]

Brian is sending me up a 3hp motor next week.



is it that the one he twisted my arm for:D

[Bryan]

so the torque drops away at low speeds...

Ray, to what extent can using a larger motor compensate for this? I doubled mine from 1 to 2 hp and was hoping that would be enough. Haven't used it enough yet to really comment on performance.

PS: Eskimo, yes Dave has a better use for it.

[eskimo]

Ray, to what extent can using a larger motor compensate for this? I doubled mine from 1 to 2 hp and was hoping that would be enough. Haven't used it enough yet to really comment on performance.

PS: Eskimo, yes Dave has a better use for it.

what about me.....:D..i missed out ...again
oh well I will just have to wait for one....or buy it.....
nah ..i dont dont need it...glad its going to someone who will use it tho, rather than the scrap bin...like where these others may end up

[BobL]

With the help of the techo (Mark) at work I have decided to go for one of these for the hercus.

SAJ 1.5KW VSD VFD inverter for fan pump - saving energy | eBay (http://www.ebay.com.au/itm/SAJ-1-5KW-VSD-VFD-inverter-fan-pump-saving-energy-/180638267385?_trksid=p4340.m263&_trkparms=algo%3DDLSL%252BPSSI%252BSI%26its%3DI%26itu%3DUCI%252BUA%252BUCK%26otn%3D20%26pmod%3D180638265403%252B180638265403%26po%3D%26ps%3D63#ht_1954wt_1141)

I realize it's about double the price of the love-happyshopping units but I simply can't bring myself to buy from someone with that name and I feel more comfortable about purchasing from a supplier located in Oz so if there are any issues with it I only have to send it back to Sydney.

Anyway, Mark is also supposedly a bit of a gun in programming these units so it will be interesting to see what he can do with it.

[Greg Q]

With the help of the techo (Mark) at work I have decided to go for one of these for the hercus.

SAJ 1.5KW VSD VFD inverter for fan pump - saving energy | eBay (http://www.ebay.com.au/itm/SAJ-1-5KW-VSD-VFD-inverter-fan-pump-saving-energy-/180638267385?_trksid=p4340.m263&_trkparms=algo%3DDLSL%252BPSSI%252BSI%26its%3DI%26itu%3DUCI%252BUA%252BUCK%26otn%3D20%26pmod%3D180638265403%252B180638265403%26po%3D%26ps%3D63#ht_1954wt_1141)

I realize it's about double the price of the love-happyshopping units but I simply can't bring myself to buy from someone with that name and I feel more comfortable about purchasing from a supplier located in Oz so if there are any issues with it I only have to send it back to Sydney.

Anyway, Mark is also supposedly a bit of a gun in programming these units so it will be interesting to see what he can do with it.

That one seems* to be a vector control (constant torque) model, and worth the extra money if it is.

*Seems to be because many VFD sellers are now using "vector drive" and similar terms to convince the unwary that the drive is constant torque when in fact its V/Hz.

I guess a question to the seller should resolve that one way or the other since he's here in Oz.

Greg

[Stustoys]

Morning Ray,
Ok I think I am even more confused. At 0 rpm even infinite torque delivers 0 power. At 1 rpm the torque would need to be 1440 times what it is at 1440rpm(right?)
Originally Posted by Stuart
Are you saying a 1440rpm motor can make 400% torque at 350rpm?


"Ok, another answer is yes, of course,..... (pause for effect)... if you have a 4:1 reduction gear box. "
This confuses me more, if you have a 4:1 gearbox the shaft is now going 87.5rpm with 4 times the torque. But the power is the same. The torque of the motor at 350rpm still needs to be 4 times what it is at 1440rpm to deliver the same power.

Do the drives increase the V(which there must be a limit on) or do they change the wave from so it has steeper raise and fall or both?
But even a square wave is only going to give so much torque...... but then where is at power going if not to the output? :no: I'll think some more, maybe I'll get my head around it.

Thanks for trying. Sorry if it feels like you are hitting your head against a wall.

Stuart

[RayG]

Ray, to what extent can using a larger motor compensate for this? I doubled mine from 1 to 2 hp and was hoping that would be enough. Haven't used it enough yet to really comment on performance.

PS: Eskimo, yes Dave has a better use for it.

Hi Bryan,

Going for a 2hp motor was a smart move.

I think it will work just fine, it all depends on what Hz the vfd is running at, let's say you are running at 50%, (25Hz) then you will still have 1hp available (roughly).

Where you might notice the drop in power is say you have the gearbox selected to 1000 rpm, and dial the vfd down to give 100 rpm, the vfd would be running at only 5Hz, you would find it hasn't got much torque, might still be usable for light cuts..

Next time you are on the lathe, give it a try, and see how slow you can go, with a high gear selected. I'm sure that there are a few others here, (myself included) who would be interested in what your thoughts are.

Regards
Ray


Ok I think I am even more confused. At 0 rpm even infinite torque delivers 0 power. At 1 rpm the torque would need to be 1440 times what it is at 1440rpm(right?)
Let me think about that for a bit, now I'm confused...:)

[Greg Q]

FWIW my lathe is a single speed belt driven with a 4:1 back gear. I am replacing its obsolete 2 hp. motor drive with a 4 h.p. induction motor. At 145 motor rpm (35 spindle rpm) it will be at around 5Hz. I figured I would need at least a 4 h.p. motor to get the required torque at that low speed. (.4 hp resulting X 4 (back gear ratio)= 1.6 h.p

I also have a 2.5 kW AC servo motor that I want to migrate to, but that has its own issues (inertia mismatch between the servo and the load).

(The above is the 1:1 motor:spindle ratio case, and I don't want to give up too much top speed. The lathe originally had 45-4000 rpm range. I don't want to go to 160 Hz+, but I would go to 120 Hz if the drive train balance is OK)

Greg

[BobL]

That one seems* to be a vector control (constant torque) model, and worth the extra money if it is.

*Seems to be because many VFD sellers are now using "vector drive" and similar terms to convince the unwary that the drive is constant torque when in fact its V/Hz.

I guess a question to the seller should resolve that one way or the other since he's here in Oz.

Greg

Too late - I ordered it on Tuesday afternoon and it was waiting for me when I arrived at work this morning. Techo Mark and I are going to try it later this afternoon - I'll report back as soon as we have something worth saying.

[EDIT] Nothing much to report other than it works as it says. We've played around a little with the setting of functions and that seems straight forward enough.
Mark is going to help me setup a switch box and bits and pieces so I can't quite plonk it on the lathe yet.

[Bryan]

Where you might notice the drop in power is say you have the gearbox selected to 1000 rpm, and dial the vfd down to give 100 rpm, the vfd would be running at only 5Hz, you would find it hasn't got much torque, might still be usable for light cuts..


That might actually be an advantage for parting. Better to stall than break stuff.



Next time you are on the lathe, give it a try, and see how slow you can go, with a high gear selected. I'm sure that there are a few others here, (myself included) who would be interested in what your thoughts are.


I can provide my freq/rpm data but not much in the way of thoughts at this stage. I will report when I've had a chance to use it more.

These are the upper and lower spindle speeds for each pulley combo (at 5Hz and 70Hz):

1: 42-628
2: 56-845
3: 71-1116

Lots of overlap. I reckon I can leave it in any of those ranges and get most things done, only belt swapping for the extreme cases. It's a lightweight machine and I don't push it hard.

[RayG]

<snip>
I also have a 2.5 kW AC servo motor that I want to migrate to, but that has its own issues (inertia mismatch between the servo and the load).


Now your'e talking real motors..... what brand? Does the controller have auto-tune?

Regards
Ray

[Greg Q]

Hi Ray...I have a pair of Allen-Bradley servos and drives, cables etc.

I collected them over a couple of years on ebay, and I am planning* to install the small one on the Deckel feed shaft to replace the chain driven shaft and change gears (Which I do not own).

*Plans change though, and there's a chance of another mill on the horizon. If that happens I'll keep the FP-1 for manual duties and leave the feeds as they are.

The whole subject of inertia mismatch came up in a PM thread. I may be OK, but the servo is pretty small compared to an induction motor (although just as heavy). I was lucky enough to buy everything new at less than 10% of new price, including some massive braking resistors. My lathe has a camlock chuck, so quick stopping won't be a problem.

Greg

[jack620]

Some good info here, thanks! While were are talking about VFD's Where is the best place to get a motor I am looking for a 1.5kw.
Will

Will,
try these guys:

Electrical Motors,3 Phase Motor,Gear Motor,Industrial Electric Motors by Royce Cross (http://www.roycecross.com.au/home.php?Operation=SetSessionVariable&Variable)[cat1]=-1&Variable[cat2]=-1&Variable[cat3]=-1&Variable[searchfilter]=-1&Variable[sqlFilter]=-1&pager=1&startpage=1&Variable[cat1sel]=-1&Variable[cat2sel]=-1

Their prices are on the website. I spoke to them today. They said "about" $25 postage for a 10kg motor (1.5HP 3 phase) to Melbourne.

[RayG]

The whole subject of inertia mismatch came up in a PM thread. I may be OK, but the servo is pretty small compared to an induction motor (although just as heavy). I was lucky enough to buy everything new at less than 10% of new price, including some massive braking resistors. My lathe has a camlock chuck, so quick stopping won't be a problem.

Greg

Can you find a link to that thread, it would be interesting to hear why anyone would think low inertia was a problem. Servo motors are specially designed to have low inertia, that why they are often long skinny things, it's so they can accelerate and decellerate faster.

The trick is to be able to tune the PID, I would expect a top of the line AC servo like Allen Bradley would have some auto-tune function.

Regards
Ray

[Bryan]

Next time you are on the lathe, give it a try, and see how slow you can go, with a high gear selected. I'm sure that there are a few others here, (myself included) who would be interested in what your thoughts are.


I can report that in high 'gear' (pulley), at 7 Hz it's quite easy to stall. At the same rpm in low, at about 12 Hz, no problems. I was facing 75mm bar at 100-odd rpm. The cut was modest, but interrupted.

[RayG]

Hi Bryan,

I'm finding similar things on the surface grinder cross feed, the torque drops away around 7-8 Hz, so I think for a rough guide to gear selection, you might get (say) 10 Hz to 70 Hz range for each gear ratio. That's a 7:1 ratio, still plenty of flexibility and would mean far less gear changes overall.

Regards
Ray

[Bryan]

Ray, yes I agree it's a vast improvement. However it's not a total solution for a lack of change gears. Not the way I've done it anyway. If I add another motor pulley to get 6 speeds instead of 3 it will be better.

BTW have you played with PD145 - auto torque compensation? I've set mine to a cautious 6 out of 10 so there's a little room to move.

[BobL]

Ray, where does 70Hz as an upper limit come from and is that for a 1450 or 2850 rpm motor?

I was discussing this with an electrical engineer at work and he was suggesting that almost all electric motors are designed to cope with at least 3000 rpm and if we think about 60Hz motors then 3450 rpm since I don't see motors made for 60Hz being any different mechanically than our 50Hz motors. So a 1450 rpm motor mechanicals should theoretically be able to cope with 1450/3450 x 50 = ~120Hz.

The mechanicals of a lathe are them probably the limiting factor of actual maximum rpm but if the lathe is operated at say a lower gear ratio then this effect is reduced.

Anyway - just exploring the origin of the 70Hz.

[Bryan]

Bob, 70 Hz if an arbitrary figure I've used as an upper limit for 2 reasons: I don't need more top end, I need more bottom end. And the motor is in retirement so I'm just being conservative. Jim Cox suggests 1.5 - 2 x nameplate speed should be quite safe. And I'm guessing he's being a bit conservative too. See "Electric Motors", Workshop Practice Series No 16, p62.

[BobL]

Bob, 70 Hz if an arbitrary figure I've used as an upper limit for 2 reasons: I don't need more top end, I need more bottom end. And the motor is in retirement so I'm just being conservative. Jim Cox suggests 1.5 - 2 x nameplate speed should be quite safe. And I'm guessing he's being a bit conservative too. See "Electric Motors", Workshop Practice Series No 16, p62.

Thanks Bryan.