Transwave inverters

[Mark P.Participant @markp]

I would like to thank Pete Moss at Transwave for his help in setting up my inverter. Can’t fault their aftersales service.

Mark P.

[Mark P.Participant @markp]

[Chris Evans 6Participant @chrisevans6]

I think it was Pete Moss that came out to sort my static inverter problems. Apparently he does not live to far from me so popped over on a Saturday morning. (I am between Lichfield and Burton on Trent so not very close to Transwave premises.)

[David Leahy 1Participant @davidleahy1]

Dear All,

I have recently purchased an elderly but well kept Smart and Brown Model 1024ss/cc lathe. This lathe is now in my small workshop awaiting connecting to some power. I have a Transwave static converter with a max loading of 4.0KW and have tried connecting this to the lathe (T1, T2, T3 neutral and of course earth). I can hear the coolant motor buzz when its turned on but do not have any response from the main motor?

Any advise here would be much appreciated. Am I connecting the Transwave converter incorrectly or is the converter of too small a power? Should it be a rotary and not a static.

My limited electrical knowledge is my downfall here but perhaps one of you more experienced engineers can advise on this?

Thankyou!

[Martin CargillParticipant @martincargill50290]

Phase convertors have a "ghost" phase. If your machine has its control circuit connected to the ghost phase it won't energise the control gear. Try swapping the phases about to see if it makes any difference.

Martin

[David Leahy 1Participant @davidleahy1]

Thankyou for that advise. I have tried what I think to be most combinations without any success? I am connecting L1, L2 and L3 and have tried moving L2 to neutral but nothing? The Transwave is lighting us as it should? I cant seem to fathom it?

[Clive FosterParticipant @clivefoster55965]

David

I presume this is the Mk 1 version of the 1024 with three speed motor. If so you probably won't be able to get it running on a static converter. I believe its technically possible to set things up so they work but you really need to know what you are doing.

Assuming the Transwave is 440 (nominal) volt output convert it (more or less) to a rotary converter by adding a pilot motor direct to the output of the converter. The pilot motor runs when the converter is switched on giving a much better approximation to real three phase. A 5 HP motor would be best. You may well need to alter the internal capacitors on the Transwave for best results. I'd be unsurprised to discover that absolute best performance needs extra switches to select the most appropriate set of capacitors for each speed.

Even with a pilot motor its advisable to ensure that the control gear is fed from the direct, transformer output phase rather than one of the generated ones. Also need to check whether Smart & Brown fitted 240 volt or 440 volt control gear. Later ones like mine could have either. 240 volt control gear needs a decently stable neutral to work well. Something converters aren't particularly good at when the motor is running up to speed.

Those 3 speed motors a lovely electrical machines but they do put horrid loads on the supply circuit as they start up and accelerate towards running speed. No issue with the national grid behind the plug but converters are something of an electrical con trick with very little capability for the abnormal.

Clive.

[David Leahy 1Participant @davidleahy1]

Hi Clive,

Many thanks for your comprehensive reply. I am not sure of the exact date of the lathe but I would imagine by the date stamped on the cast main switch cover at the rear of the lathe it is early 80's as the stamp states 1979.

I am happy to invest in a rotary converter if this will do the job but didn't want to go to further expense (especially now being in the wife's bad books for buying to much equipment in the 1st place!) if I can make do with the one I have, the Transwave static I have is as follows:

5.5kw max loading

max single motor 4kw

0.75kw min loading

input 230

output 400v

50Hz

If I were to invest in a rotary converter would this be capable of running the control gear and the 3 speed motor sufficiently? I can always sell the static I have if a rotary would be a better option?

Any advice is greatly appreciated. I would hate to buy another piece of kit and not have it working still?

Best regards,

David.

[Clive FosterParticipant @clivefoster55965]

David

First take look at **LINK** and verify whether yours is a MK 1 with the 3 speed motor or a MK 2 VSL with single speed motor and variable speed belt drive. I don't know when the MK2 VSL version of the 1024 was introduced but late 1970's has the right feel. If it is a MK2 life is much, much easier.

A static converter will still struggle on a MK2 because there is no clutch so it has to run up the spindle and drive every time. Simply adding a pilot motor should sort that.

Talk to Transwave, they are helpful folk and have the experience to know the best way to drive whichever motor you have.

In similar circumstances on another breed of machine, albeit with a two speed rather than three speed motor, simply adding a 5 HP pilot motor to a 4KW static converter got things running well enough. That was a MotoRun converter but a Transwave is essentially similar.

I run my 1024 VSL off a 220 V in / 440 V out VFD box from Drives Direct. Mine is 10 HP "whole shop" unit permanently set to 50 Hz and runs everything a treat. Very expensive but, so far as the machines are concerned its proper 3 phase from the grid. A smaller, single machine, VFD works fine on the VSL too but you do need to re-jig the controls to operate the VFD direct.

I suggest you sign up with the Smart & Brown group on Yahoo as there are members with direct experience of setting up static or rotary converters on the 1024.

Clive.

 

Edited By Clive Foster on 16/09/2017 18:05:51

[David Leahy 1Participant @davidleahy1]

Thankyou again for your comprehensive reply. I can confirm from the images in the link that my lathe is the VSL model. Also I have viewed the Yahoo Smart and Brown group and this looks like a great resource.

Regarding a VSL, I have purchased one for a band saw so I guess I could use this? If I do use the VSL am I correct in thinking that I will have to wire direct to the motor and loose the functionality of the buttons on the front of the machine? It is an option that I would consider but have no idea as yet to the wiring?

[larry PhelanParticipant @larryphelan54019]

Not sure if this will be of any help to you,but here goes,anyway.

I had a static converter,on loan,some time ago,to see if it would run my planer and spindle moulder. I t would not .,just gave a buzzing noise when I pressed the starters [each machine had 4hp motors ] Would run my lathe and mill OK 1/2 hp each,even both together. Got fed up and bought a rotary converter,set it up and away she went !

Now I just switch on and get stuck in. I think you may be better off to just buy a rotary job and be finished with it. There is no messing about adjusting anything to suit loads.

[David Leahy 1Participant @davidleahy1]

Hi Larry,

Thankyou for that. That is exactly what I am experiencing with my lathe. I was wondering about the rotary. I think I will do just that and buy a rotary.

Thankyou.

[Clive FosterParticipant @clivefoster55965]

David

Three motors on a VSL so rotary is the easiest way by far.

Do talk to Transwave first because a rotary is pretty much just a static converter with a permanently connected pilot motor and it may be possible to convert yours for less money overall than selling the static one and buying a rotary.

Big disadvantage of rotaries is that there is another motor buzzing round which can be annoying. Whatever you do don't put it on a shelf or its likely to set the whole workshop going. Found that out the hard way!

Clive.

[Matt de HoestParticipant @mattdehoest99598]

Worth looking at L1, L2 and L3 again. As others have said – if control circuitry is connected to phantom phase it dont work. I think L1 and L2 are OK but running control circuits off L3 leads to symptoms similar to those you have described. Static converters are fine where a single motor is supplied (or even single main motor + coolant motor with negligable draw) but you need to set the output power usually with a rotary switch. Eg – if you have one motor at 1hp and another at 2hp you need to manually change the output power to 1hp or 2hp depending on which motor your running (or 3hp where youre running both). Might be worth checking your converters output matches your motor's draw. Static converter output frequency is fixed so motor speed is fixed. VFD probably better for a single motor: relatively cheap, infinate speed control etc and small 3phase motors (coolant motor) can be rewound for single phase quite easily/cheaply apparantly. The VFD control then replaces the stock motor controls on the lathe and only allows control of the drive motor. I chose a rotary as my machine has two motors (main and power-feed) hence constantly change the power draw as i operate the machine. With a rotary there is no need to set any output and minimum draw is 0. Much easier for multi-motor or multi-machine operations. I phoned transwave for help when buying and after buying to help set up – they were really helpful and sympathetic to my lack of knowledge!! They also sell inverters.

Best wishes

Matt

Edited By Matt de Hoest on 18/09/2017 22:25:24

[David Leahy 1Participant @davidleahy1]

Thankyou for that detail Matt. I will give it another check and see what I can do further.

Cheers,

Dave.

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