Here is a list of all the postings Ewan Turnbull has made in our forums. Click on a thread name to jump to the thread.
Thread: Boxford motor help |
26/06/2020 18:22:03 |
Posted by Howard Lewis on 26/06/2020 16:12:14:
Not sure what make the VFD is on my lathe. It came as part of the deal. (Free fitting if ordered at the same time as the lathe ) Unless the pendant is a generic one, it looks like a Newton Tesla? The standard single phase 1470 rpm motor was a 2 hp. I asked for 1.5 hp three phase motor, since I thought that it would be an equivalent. The VFD has been in use, not daily, but many times long enough for the cooling fan to cut in, and is still functioning after 16, nearly 17 years, so could be described as being reliable. The motor spends most of its time being run at maximum sped. Howard Hi Howard I'd say 16-17 years qualifies as reliable |
25/06/2020 18:46:36 |
Thanks Harry My workshop converter is also a transwave that I bought almost 20 years ago and it's still going strong - they do good stuff but seem to be a bit more £££ than some of the others. I'll have a wee youtube session and see if I can expand my VFD knowledge Cheers Ewan |
25/06/2020 11:53:22 |
Hi NDIY - scuse my rushed maths fair point about upgrade one part - consider the rest. I've emailed Inverter Drive Supermarket and asked them to recommend a VFD/motor combo - any other reliable companys that folk would recommend trying?
cheers |
25/06/2020 09:40:45 |
Posted by Harry Wilkes on 24/06/2020 22:00:44:
Evan I would say stay with a 4 pl 1500 motor .75 HP or even move up to a 1HP buy your inverter or a inverter /motor pack from reputable supplier who can give you advice and support if needed, and as NDIY pointed out if you need to go slow with torque put it into back gear. One of the advantages of fitting a VFD is that it gives you some speed adjustment for a given pulley combination. Look at it this way do you need to fit a DRO no does it make life easier yes same goes for a VFD H Edited By Harry Wilkes on 24/06/2020 22:03:48 Thanks for this good advice Harry (& thanks to SM as well) I think it's time to get on with this as I have a few wee jobs starting to build up and I'm looking forward to having some fun with this wee thing. CB1 mentioned Inverter Drive Supermarket on an earlier post - based on your experience are there any other reputable suppliers out there I should be looking at? |
24/06/2020 21:52:03 |
Posted by old mart on 24/06/2020 21:45:32:
Having a VFD controlled motor is an addition to using pulleys and back gear, not a lazy persons substitute.
this is a real good point and is the reason I went back to the woodlathe - my mate had sold it to me as variable speed control and no need to change belts but as you rightly say, thats the lazy way. I can't really fault my mate as he's not into woodturning and was when it all comes down to it, just doing me a good turn
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24/06/2020 21:42:45 |
thanks to both Clive 1 and not done it yet for the comments - good common sense advice regarding not going overboard - the original motor was a 3 phase 3/4hp so a 25% increase to a 1hp used sensitively might be the way to go.
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24/06/2020 20:16:11 |
Posted by Andrew Tinsley on 24/06/2020 10:57:49:
If going the VFD route, then it is worth putting in a more powerful motor, if it will fit. The reason being that at lower RPM the torque available is reduced with a VFD.. Putting in a more powerful motor returns the torque to a higher figure. Andrew. Hi Andrew would a jump from 4 pole 3/4HP to 4 pole 1HP be enough to overcome the torque problem? cheers ewan |
24/06/2020 20:13:41 |
So - time to give the full backstory I have a wee workshop beside my garage which I use for woodwork - having a combined workshop in the garage wasn't good - wood don't like engine oil and engines don't like sawdust! I have a 3 phase converter which i originally had running my wadkin bursgreen bandsaw and my Union Graduate lathe. Both ran great but I got a bit fed up changing the connection and settings on the converter every time I wanted to work the 'other' machine. One day a friend offered to add some weird gizmo -that I now know to be a VFD - to my woodlathe to allow it to be fed straight from the 240v supply. Ideal said I, after he told me about the variable speed etc. However..... when roughing or turning larger dia wood blanks - specially out of balance blanks the woodlathe has to be run at fairly low RPM and it just doesn't have anywhere near the torque it had before the conversion and it kind of spoiled my experience to the point that I avoided woodturning for a good couple of years. Spring forward to current times and I am looking to get a system that will work my Boxford in the way it's meant to be used....... I was right on the point of ordering a 3 phase + VFD when Speedy made his point about the reliability of VFD's and the cost of replacement. I'm happy to spend a wee bit more - looked at the website recommended earlier and its around £200 - £220 for the complete 3 phase system with VFD - if it will give me the best solution. There does seem to be an argument for single phase from a cost point of view although as previously mentioned - I'm a bit clueless in this area and don't really know what else I need, do I just buy a motor (££?) and pop that in and it works or do I need other gubbins and have to rework switches etc? I'm still leaning towards the 3 phase but want to make sure if I do go that route that I get a reliable VFD . I'm also really enjoying all these different points of view and appreciate all the advice folks are giving. I'm happy to take the time and listen to folks to make sure I opt for the best all round solution thanks again
ewan |
24/06/2020 19:49:48 |
Posted by Andrew Tinsley on 24/06/2020 10:57:49:
If going the VFD route, then it is worth putting in a more powerful motor, if it will fit. The reason being that at lower RPM the torque available is reduced with a VFD.. Putting in a more powerful motor returns the torque to a higher figure. Andrew. Hmm that was one of my concerns cheers |
24/06/2020 10:23:51 |
Posted by Harry Wilkes on 20/06/2020 21:57:19:
Roughly 2 pl 3000 4pl 1500 6pl 1000 RPM any new motor you buy should be marked 415/240 volts star is 415v delta is 240v when using a 240v inverter the motor needs to be wired for 240v If you buy from a supplier of inveter/motors you will get the correct motor but you will need to check it's wired in delta Hope this helps H Hi Harry ideal explanation - simple and to the point informed is always better cheers E |
20/06/2020 21:32:13 |
Posted by Phil Whitley on 20/06/2020 21:29:29:
remember too that if your VFD outputs 240v 3 phase you will need a motor that can be connected in Delta, but if you go for the VFD with 415 volt output the motor can be run in star. Some modern small motors do not bring the star point into the terminal box, and therefore they cannot be connected in delta. Phil Sorry Phil - I'm showing my woeful lack of knowledge on electrical matters - star / delta? i get your point about being careful to match the VFD output to the motor but is there a difference / benefit to delta over star or vice versa? thanks Ewan Edited By Ewan Turnbull on 20/06/2020 21:32:40 |
20/06/2020 21:29:27 |
so - these replies have raised another question.... 2 pole? 4 pole? 6 pole? ?????whats the difference / benefit
thanks again Edited By Ewan Turnbull on 20/06/2020 21:29:41 |
20/06/2020 21:18:45 |
Posted by Clive Brown 1 on 20/06/2020 11:30:42:
Is your lathe an underdrive or a bench model? I've got a bench type ME10. To go the VFD route, I found that the largest frame size motor I could fit without too much surgery of the mounting was a 71. I bought a TEC 0.75kW, 1440 rpm motor from Inverter Drive Supermarket. A 71 frame metric motor will have a 14mm dia. shaft, so the pulley needs to be sleeved You might find an imperial sized motor but prices seem to be higher. If a CUD, can't really advise on motor dimensions. A VFD makes lathe operation much more convenient IMO. Edited By Clive Brown 1 on 20/06/2020 11:32:41 Hi Clive it's an underdrive model so space is a bit limited. thanks for the heads up on Inverter drive supermarket cheers |
20/06/2020 21:15:30 |
Posted by Speedy Builder5 on 20/06/2020 10:48:21:
I have had a Southbend, then an AUD Boxford for 50 plus years 3/4Hp single phase. If you have the money, 3 phase seems to be the way to go, but its only 30 seconds for a belt speed change on mine. Also, there are several posts where the VFD has stopped working - Well its just a matter of more money, I would prefer to spend the money on making things! If you were doing a lot of large face work using a powered cross feed, then variable speed would be handy...but how often? On the basis that the model C doesn't have powered cross feed I would question the reason why you wanted a VFD ? Hi Speedy to be totally honest - I don't really know. I'm a time served turner and am used to 3 phase but this is just a wee lathe for doing the odd bit of turning at home - mainly motorcycle related and the odd job for a few of my mates that are into steam engines etc. As i'm not looking to use it to earn income I don't really want to spend any more than I need to to get it running reliably - whats the rough price difference between 1 & 3 phase? always good to have a variety of opinions from experienced users. cheers |
20/06/2020 21:09:32 |
Posted by SillyOldDuffer on 20/06/2020 10:25:21:
As Dave Halford says, first identify the frame (standard sizes for both Imperial and Metric), so the motor will physically fit. Then find a motor in that size, with the wanted volts, power output and RPM. It may be possible to find a VFD & Motor Package, which comes with instructions and simplifies installation - maybe Newton-Tesla. Otherwise the forum is good at answering motor questions. A moderately more powerful motor wouldn't do much harm, (say 1HP rather than 0.85HP) but do you really know better than the bloke who designed the lathe? More power puts more stress on the machine all round. It also increases the amount of damage in the event of a crash and the risk of personal injury. Doubling the motor power, or more, is asking for trouble in my opinion, especially if the motor can be over-sped with a VFD as well. Lathes aren't like cars where improved acceleration is a benefit; on a lathe big motors can only do more work faster, which risks thrashing the machine. Big motors on small machines don't produce better finish or improve accuracy. Of course, it's your machine and you can do what you like with it! Chewing metal at high-speed, or delicate precision... Have fun! Dave Thanks for this Dave - I was thinking about maybe going up to the 1hp to give it that wee bit more oomph but agree with your point about going silly with power being an accident waiting to happen. thanks for the advice |
20/06/2020 21:06:23 |
Posted by Dave Halford on 20/06/2020 09:32:54:
You can use THIS to work out the existing frame size that you have from the bolt spacing. Then buy the same in 3phase as frame sizes are standardised. Dave This is really handy - that was going to be my next question was how do I get a like for like fit
cheers |
19/06/2020 21:28:49 |
Hi Folks I've had a look at a few threads and the question I was going to ask - single or 3 phase - has been answered - (thanks so much for all of these informative posts), 3 phase seems to be the way to go. so that moves me on to question 2.....
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