3 phase vs 2 phase nema 34

[mbridge87]

Hello,

I'm very new to all this, lots to learn, so apologies for my lack of knowledge.

I'm currently building a motion control rig for videography and need a little help. Getting straight to the point, is there any downside to having a 3-phase rather than 2-phase motor? Are there any special considerations when using a 3-phase motor?

The reason I ask is I accidentally ordered a heavy duty slider from China not realising it had a 3-phase motor. All my planning and purchasing has been around 2-phase motors. I'm now wondering whether I should switch out the 3-phase motor for a 2-phase one or change my driver?

These are all the components I currently have:

Slider - https://www.fuyumotion.com/heavy-duty-compact-ball-screw-linear-axis-robot-arm.html

Large driver for slider - https://www.omc-stepperonline.com/digital-stepper-driver/digital-stepper-driver-0-5-8-2a-180-240vac-for-nema-34-42-stepper-motor.html?sort=p.price&order=DESC

PSU - https://www.omc-stepperonline.com/350w-48v-73a-115230v-switching-power-supply-stepper-motor-cnc-router-kits-s-350-48.html?search=350W%2048V%207.3A%20115%2F230V%20Sw itching%20Power%20Supply%20Stepper%20Motor%20CNC%2 0Router%20Kits

4 of these drivers - https://www.omc-stepperonline.com/digital-stepper-driver-10-42a-20-50vdc-for-nema-17-23-24-stepper-motor-dm542t.html?search=Digital%20Stepper%20Driver%201. 0-4.2A%2020-50VDC%20for%20Nema%2017%2C%2023%2C%2024%20Stepper% 20Motor

Motion controller - https://www.bfg-motion.com/index.php?p=1_4

I can either purchase a 2-phase motor from the same supplier or a 3-phase driver.

Alternate driver - https://www.omc-stepperonline.com/digital-stepper-driver/digital-stepper-driver-2-1-11-7a-176-253vac-for-3-phase-nema-34-42-stepper-motor.html?sort=p.price&order=DESC

Alternate motor - 28725

I'd really appreciate any help and advice.

Thanks,

Max

[JAZZCNC]

Ok well, 3 phase will actually be better for a photo rig because often 3ph motor as a lower step angle, often 1.2 deg rather than 1.8Deg of a standard stepper so give a smoother action, but this will depend on the motor. Thou in any case 3ph is smoother and are stronger motors in general because of the extra phases so will always be better than 2ph stepper in this environment as you can crank up the micro-stepping on the drives which helps to smooth the action of the motors.

But to be honest I'm wondering why your going with a stepper system, and a cheap one at that, on such a high-end motion control rig.?
DC or AC servo will be much much smoother and the motion controller is capable of 500Khz so will easily handle higher resolution encoders which is what gives you the smoothness and resolution.
Obviously they are more expensive but I would have thought a price worth paying if you are prepared to go high-end on the controller, It's a little like having a Ferrari engine and fitting skinny little tyres with weedy brakes.!!

[mbridge87]

Ok well, 3 phase will actually be better for a photo rig because often 3ph motor as a lower step angle, often 1.2 deg rather than 1.8Deg of a standard stepper so give a smoother action, but this will depend on the motor. Thou in any case 3ph is smoother and are stronger motors in general because of the extra phases so will always be better than 2ph stepper in this environment as you can crank up the micro-stepping on the drives which helps to smooth the action of the motors.

But to be honest I'm wondering why your going with a stepper system, and a cheap one at that, on such a high-end motion control rig.?
DC or AC servo will be much much smoother and the motion controller is capable of 500Khz so will easily handle higher resolution encoders which is what gives you the smoothness and resolution.
Obviously they are more expensive but I would have thought a price worth paying if you are prepared to go high-end on the controller, It's a little like having a Ferrari engine and fitting skinny little tyres with weedy brakes.!!

Thanks for the reply. So would it be best to simply grab that alternate driver, the 3DM2283T? Will it all hook up ok with what I have?

In terms of why that motor, it came down to budget. My budget for this project has gone up and up and it's now around £4k, which includes all the other bits and pieces I need for building the camera rig, control box, cables etc. I just can't afford more right now, COVID has been tough for business and I've been selling all the unused kit I can get my hands on to afford this.

I'm hoping this current build will at least outperform most consumer motion control units; Edelkrone, eMotimo, Rhino etc. Then in the future I'll upgrade to other parts and improve it further.

I was originally going to go with Dragonframe (didn't know any better) but realised that to get live motion I needed their very expensive controller. That then led me to Mantis and Gerald, who makes the controller and software, he's been really kind in advising me what to get. It's all been a balancing act with budget as I'm sure you can imagine.

I take it I can upgrade the motors down the line? Would better motors work ok with the drivers I've already got? Are these the sort of thing you mean:

https://www.omc-stepperonline.com/servo-stepper-motor/

Thanks again.

Max

[mbridge87]

Thanks for the reply, I appreciate it.

So it would be ok to get that alternate Driver, the 3DM2283T? That will work ok with the items I currently have?

In terms of why these motors, honestly it comes down to budget. My original budget has gone up and up, it’s now around £4k, which includes other items, pan unit, tilt unit (linked below), rig for camera, lens motor, control box etc. and I just can’t put in anymore right now. COVID has decimated my business this year so the only way I can afford this is by selling every unused piece of kit I have.

I’m using two of these for the pan and tilt units - https://www.aliexpress.com/item/1661601847.html

My hope is that this system will at least out-perform most consumer motion control units; Edelkrone, eMotimo, rhino etc. In the future I’ll then upgrade parts once budget allows.

Gerald, the guy who designs and builds the Mantis controller, has been extremely helpful giving me advice on what parts to buy. As you can imagine, it’s been a balancing act in terms of budget.

Just so I know for future reference, what sort of Servo motors would you recommend?

[mbridge87]

Sorry for the double post. I did the first one but it didn't appear so I wrote it again and now they're both there...

[johnsattuk]

Could go 5 phase :lemo:

[JAZZCNC]

The 3DM2283T will certainly do the job but it's most likely massive overkill for what you are doing which might not a positive thing.?. I say most likely because I'd need to know more about the spec of Motor you have to be 100% sure, Size, inductance etc.

Here's why it might not be a positive thing.! The DM2282T you have already and the 3DM2283T are High voltage drives which you only really need with very large motors or very High inductance motors.
They are kind of drive I would fit on a Router with Large Nema 34 motors in the 10Nm to 15Nm range which is required to spin at the highest speed possible and still provide strong torque at higher RPM. You won't need speed for this application or High torque at high RPM I would presume.

For a Lower size Nema 34 motors ie: 4Nm to 8Nm range with low to medium inductance then they may get too hot if you run them at 230v Mains voltage which I presume you are going to do as I don't see any transformers on your list.!
The heat will make the motors run rough and eventually over time slowly get rougher until they kill the motors altogether.

Again without knowing the full spec of the motors and the weights you are shifting it's difficult to be accurate but I've got a fair bit of camera equipment my self with large heavy lenses etc and I can't imagine any situation where a 4Nm or 6Nm NEMA 34 motor on a linear stage with a ball screw would require more than 80Vdc. To be honest even a Nema 23 with 50 to 60Vdc would easily handle it.

This brings me on to the next thing I see. The 4 x DM542T and the 48V PSU. The DM542T drives are 50Vdc Max voltage and with 48vdc your running very close to the limit, now in this application which will be relatively slow-moving with low inertia you'll probably be ok and get away with it. But if this was a router or fast-moving device with a heavy load and high inertia I'd recommend you went with a low voltage PSU due to the fact a stepper becomes a dynamo when de-accelerating and will dump power back into the drives which can cause them to be damaged. Ideally, you should allow a 10% safety margin on the drives Max voltage, Often these PSU have an adjustment pot which you can use to tune the voltage, if it does I suggest you lower it as a safety precaution.

When it comes to steppers BIGGER isn't always better and it's common for people to fall foul of this and go with large Nema 34 motors. Happens all the time on Milling conversions where they think the little motors can't lift the heavy Milling heads or tables when in reality not only do they do this easily they actually often allow higher feed rates than the larger Nema 34 motors.!

[JAZZCNC]

Just so I know for future reference, what sort of Servo motors would you recommend?

I would need to know more about the weights your moving and linear stage etc but any 200W AC servo would probably do what you need or 400W at most I would think. Even something like this 180W DC with integrated drive would be enough I'd guess, esp if used a gearbox.
https://www.ebay.co.uk/itm/180W-3000rpm-0-6Nm-57-Integrated-Servo-Motor-NEMA23-36V-JMC-iHSV57-30-18-36-DE/264268594764?_trkparms=aid%3D1110006%26algo%3DHOME SPLICE.SIM%26ao%3D1%26asc%3D225076%26meid%3Da9890b 1aadce465fa08da2acb133b89d%26pid%3D100005%26rk%3D3 %26rkt%3D12%26mehot%3Dco%26sd%3D283049525706%26itm %3D264268594764%26pmt%3D1%26noa%3D0%26pg%3D2047675 %26algv%3DSimplAMLv5PairwiseWebWithDarwoV3BBEV1%26 brand%3DUnbranded&_trksid=p2047675.c100005.m1851

Don't be fooled by the low Nm rating, Servo's are very different to steppers and the rating is constant across the RPM range so you'll have the rated Torque at full speed which is often 3000rpm, this is between 2x to 3x faster RPM than a stepper will reach which is why you can use a gearbox to increase torque and still have the same rpm as a stepper. Also, they can often peak at 3x the rated torque for 10-20s which is often more than enough to overcome any friction and get things rolling.

[Kitwn]

Max,
It was making a basic camera motion control system for timelapse and animation (driven by Dragonframe) that first got me into playing with stepper motors and then onto building a CNC router. Be warned!

Back then there was a very active group on the forum of the TIMESCAPES website who were building their own gear, some of which was designed to be used for professional work. Gerald at Mantis was quite active on there for a while. Sadly the activity has died away over recent years but the archive of material might be of use to you.

Kit

http://forum.timescapes.org/phpBB3/viewforum.php?f=24

[mbridge87]

The 3DM2283T will certainly do the job but it's most likely massive overkill for what you are doing which might not a positive thing.?. I say most likely because I'd need to know more about the spec of Motor you have to be 100% sure, Size, inductance etc.

Here's why it might not be a positive thing.! The DM2282T you have already and the 3DM2283T are High voltage drives which you only really need with very large motors or very High inductance motors.
They are kind of drive I would fit on a Router with Large Nema 34 motors in the 10Nm to 15Nm range which is required to spin at the highest speed possible and still provide strong torque at higher RPM. You won't need speed for this application or High torque at high RPM I would presume.

For a Lower size Nema 34 motors ie: 4Nm to 8Nm range with low to medium inductance then they may get too hot if you run them at 230v Mains voltage which I presume you are going to do as I don't see any transformers on your list.!
The heat will make the motors run rough and eventually over time slowly get rougher until they kill the motors altogether.

Again without knowing the full spec of the motors and the weights you are shifting it's difficult to be accurate but I've got a fair bit of camera equipment my self with large heavy lenses etc and I can't imagine any situation where a 4Nm or 6Nm NEMA 34 motor on a linear stage with a ball screw would require more than 80Vdc. To be honest even a Nema 23 with 50 to 60Vdc would easily handle it.

This brings me on to the next thing I see. The 4 x DM542T and the 48V PSU. The DM542T drives are 50Vdc Max voltage and with 48vdc your running very close to the limit, now in this application which will be relatively slow-moving with low inertia you'll probably be ok and get away with it. But if this was a router or fast-moving device with a heavy load and high inertia I'd recommend you went with a low voltage PSU due to the fact a stepper becomes a dynamo when de-accelerating and will dump power back into the drives which can cause them to be damaged. Ideally, you should allow a 10% safety margin on the drives Max voltage, Often these PSU have an adjustment pot which you can use to tune the voltage, if it does I suggest you lower it as a safety precaution.

When it comes to steppers BIGGER isn't always better and it's common for people to fall foul of this and go with large Nema 34 motors. Happens all the time on Milling conversions where they think the little motors can't lift the heavy Milling heads or tables when in reality not only do they do this easily they actually often allow higher feed rates than the larger Nema 34 motors.!

Thanks so much for the detailed reply.

This is the spec of the 3-phase Nema 34 motor I currently have for the slider – 28728
This is the spec of the 2-phase motors in the rotation stages which are being run by the DM542T drivers - https://www.makeblock.com/project/42byg-stepper-motor

Having looked at the specs of the Nema 34 motor (holding torque 7Nm), it seems like the suggested Driver may be overkill. What would you suggest using instead?

To give you a little more info on this part of the build, the slider will have a pan tilt head attached, sometimes a cinema camera (Red DSMC2, Alexa mini), sometimes a smaller camera, plus a focus motor and some rigging items like camera plates etc. I’d estimate the total weight of this to be 12-16kg depending on the camera, lens etc.

The slider will need to move that weight both horizontally, and vertically.

In terms of wiring, if I’m honest this part has been the most confusing to me. There are loads of resources online for CNC but I didn’t know what was relevant to me and have ended up quite confused after watching loads of YouTube videos. Some seem very simple, just drives, PSU, BOB and controller, others involve all manner of additional items. So, no I wasn’t planning to use a transformer but happy to incorporate one if need be.

Would you recommend getting a different PSU for the 4 x DM542T drivers? Something with a lower 36V like this for example - https://www.omc-stepperonline.com/power-supply/350w-36v-97a-115230v-switching-power-supply-stepper-motor-cnc-router-kits-s-350-36.html?sort=p.price&order=DESC

Again, I’m very appreciative of the advice. Wish I’d found this forum earlier. I can probably return some of these items, the larger Driver and PSU and switch them out for other components so hopefully won’t waste much money here.

If you have any other suggestions I’d love to hear them.

[mbridge87]

I would need to know more about the weights your moving and linear stage etc but any 200W AC servo would probably do what you need or 400W at most I would think. Even something like this 180W DC with integrated drive would be enough I'd guess, esp if used a gearbox.
https://www.ebay.co.uk/itm/180W-3000rpm-0-6Nm-57-Integrated-Servo-Motor-NEMA23-36V-JMC-iHSV57-30-18-36-DE/264268594764?_trkparms=aid%3D1110006%26algo%3DHOME SPLICE.SIM%26ao%3D1%26asc%3D225076%26meid%3Da9890b 1aadce465fa08da2acb133b89d%26pid%3D100005%26rk%3D3 %26rkt%3D12%26mehot%3Dco%26sd%3D283049525706%26itm %3D264268594764%26pmt%3D1%26noa%3D0%26pg%3D2047675 %26algv%3DSimplAMLv5PairwiseWebWithDarwoV3BBEV1%26 brand%3DUnbranded&_trksid=p2047675.c100005.m1851

Don't be fooled by the low Nm rating, Servo's are very different to steppers and the rating is constant across the RPM range so you'll have the rated Torque at full speed which is often 3000rpm, this is between 2x to 3x faster RPM than a stepper will reach which is why you can use a gearbox to increase torque and still have the same rpm as a stepper. Also, they can often peak at 3x the rated torque for 10-20s which is often more than enough to overcome any friction and get things rolling.

Interesting, thanks for showing that to me. For the moment I think it still makes sense financially to stick with what came with the slider and rotation stages but in V2 of this machine, sometime down the line, I'd definitely build it with better motors as you suggest. There was an option to add a servo to the slider but it increased the cost but something like £200 so I had to pass.

I gave a bit more info about what I'll be moving, weights etc. and how, above. Essentially, 12-16kg being moved both horizontally and vertically. In the future that may increase if I were to add multiple sliders together to give me both horizontal and vertical movement simultaneously.

[mbridge87]

Max,
It was making a basic camera motion control system for timelapse and animation (driven by Dragonframe) that first got me into playing with stepper motors and then onto building a CNC router. Be warned!

Back then there was a very active group on the forum of the TIMESCAPES website who were building their own gear, some of which was designed to be used for professional work. Gerald at Mantis was quite active on there for a while. Sadly the activity has died away over recent years but the archive of material might be of use to you.

Kit

http://forum.timescapes.org/phpBB3/viewforum.php?f=24

Hi Kit,

Thanks for the reply. I actually found that forum a while ago, even tried to sign up before I realised it was no longer operating. Trouble was I needed to ask questions and there was nobody there to help. Hopefully I can run a few things past people here.

When you say "be warned!" can you elaborate? Was it a nightmare for you?

Thanks,

Max

[Kitwn]

Hi Kit,

Thanks for the reply. I actually found that forum a while ago, even tried to sign up before I realised it was no longer operating. Trouble was I needed to ask questions and there was nobody there to help. Hopefully I can run a few things past people here.

When you say "be warned!" can you elaborate? Was it a nightmare for you?

Thanks,

Max

Timescapes was a great place to hang out as well as learn a lot of stuff. I was inspired to move into animation from timelapse and to build my first CNC router design by friends I made on there. I even got into making timelapse films of turtles nesting on the beaches near where I live in Western Australia using only moonlight after one forum member in Florida started doing something similar. Once we got to the point that every mobile phone could do timelapse and the regulars who were on the forum got busy making use of the machines they'd made activity died down.

"be warned!": Not a nightmare at all, I've found the whole process of starting with a wood and allthread 'proof of concept' machine and working my way up to something capable of serious work a very rewarding project in it's own right (not that I recommend that route at all!) But it has been time consuming and once you have made the CNC machine you have to find things to make with it. Other people (aka wife) will also find all sorts of things for you to make with it and it tends to become central to all the other projects you have in mind since it can make the pieces better and quicker than you can.

Kit

[mbridge87]

Timescapes was a great place to hang out as well as learn a lot of stuff. I was inspired to move into animation from timelapse and to build my first CNC router design by friends I made on there. I even got into making timelapse films of turtles nesting on the beaches near where I live in Western Australia using only moonlight after one forum member in Florida started doing something similar. Once we got to the point that every mobile phone could do timelapse and the regulars who were on the forum got busy making use of the machines they'd made activity died down.

"be warned!": Not a nightmare at all, I've found the whole process of starting with a wood and allthread 'proof of concept' machine and working my way up to something capable of serious work a very rewarding project in it's own right (not that I recommend that route at all!) But it has been time consuming and once you have made the CNC machine you have to find things to make with it. Other people (aka wife) will also find all sorts of things for you to make with it and it tends to become central to all the other projects you have in mind since it can make the pieces better and quicker than you can.

Kit

Ah ok, glad to hear it wasn't a nightmare to get everything operational. I was concerned.

I don't plan to build a CNC machine, rather a motion control video rig. That said having looked into this for so long a CNC machine would be pretty cool!

[Kitwn]

That said having looked into this for so long a CNC machine would be pretty cool!

See, you're on the slippery slope already :excitement:

My own moco rig was simply a slider which was not used for real-time video which requires MUCH smoother motion. I know the Timescapes forum has dried up but if you want more info on some of the rigs described there the same people are probably still about on different sites. Just for a taster, here's a video of a rig built by a man who is known online as DISPLACEMENT1 who works in an impossibly small garden workshop and equally small living room in Manchester and has been working in professional animation for many years.

https://vimeo.com/177889250

Kit

[mbridge87]

See, you're on the slippery slope already :excitement:

My own moco rig was simply a slider which was not used for real-time video which requires MUCH smoother motion. I know the Timescapes forum has dried up but if you want more info on some of the rigs described there the same people are probably still about on different sites. Just for a taster, here's a video of a rig built by a man who is known online as DISPLACEMENT1 who works in an impossibly small garden workshop and equally small living room in Manchester and has been working in professional animation for many years.

https://vimeo.com/177889250

Kit

Looks pretty amazing! Love the music.

My intention for the moment is to build a rig which will allow me to produce a portfolio of motion control video work. I'd then approach ad agencies, direct brands etc. and have the work to show. If actually booked for a job then I can either use the kit I've built, if suitable for the job, or bring on people like G6 Moco - https://www.instagram.com/g6moco/

I'm currently a still life photographer and on large advertising shoots there should be the budget to bring in people with far more advanced rigs then I could ever build. This whole process gets my foot in the door and teaches me a little of what I need to know.

This is my still life work - https://www.max-bridge.com/

[Kitwn]

This is my still life work - https://www.max-bridge.com/

Nice! I like the liquid splash work for Max Factor.

This was my one and only animated film. Took so bloody long with me doing EVERYTHING required from designing and building the moco rig and high stability LED lights to improvising the music that I hadn't the will power to make another one.

https://vimeo.com/137467870

Kit

[mbridge87]

Nice! I like the liquid splash work for Max Factor.

This was my one and only animated film. Took so bloody long with me doing EVERYTHING required from designing and building the moco rig and high stability LED lights to improvising the music that I hadn't the will power to make another one.

https://vimeo.com/137467870

Kit

Nice! Love the dog at the beginning, made me laugh

[mbridge87]

I would need to know more about the weights your moving and linear stage etc but any 200W AC servo would probably do what you need or 400W at most I would think. Even something like this 180W DC with integrated drive would be enough I'd guess, esp if used a gearbox.
https://www.ebay.co.uk/itm/180W-3000rpm-0-6Nm-57-Integrated-Servo-Motor-NEMA23-36V-JMC-iHSV57-30-18-36-DE/264268594764?_trkparms=aid%3D1110006%26algo%3DHOME SPLICE.SIM%26ao%3D1%26asc%3D225076%26meid%3Da9890b 1aadce465fa08da2acb133b89d%26pid%3D100005%26rk%3D3 %26rkt%3D12%26mehot%3Dco%26sd%3D283049525706%26itm %3D264268594764%26pmt%3D1%26noa%3D0%26pg%3D2047675 %26algv%3DSimplAMLv5PairwiseWebWithDarwoV3BBEV1%26 brand%3DUnbranded&_trksid=p2047675.c100005.m1851

Don't be fooled by the low Nm rating, Servo's are very different to steppers and the rating is constant across the RPM range so you'll have the rated Torque at full speed which is often 3000rpm, this is between 2x to 3x faster RPM than a stepper will reach which is why you can use a gearbox to increase torque and still have the same rpm as a stepper. Also, they can often peak at 3x the rated torque for 10-20s which is often more than enough to overcome any friction and get things rolling.

Hey Jazz, hope you had a good week. Just wondering if you saw my messages giving a bit more info about the build? I'd love your opinion about the correct driver for the NEMA 34 and PSU.

Thanks,

Max

[JAZZCNC]

Hey Jazz, hope you had a good week. Just wondering if you saw my messages giving a bit more info about the build? I'd love your opinion about the correct driver for the NEMA 34 and PSU.

Thanks,

Max

No, I've been busy this week so not had much time, I'll go back and have a look come back to you.

[JAZZCNC]

This is the spec of the 3-phase Nema 34 motor I currently have for the slider – 28728

Ok well, that's a whopping 14mh which is common for Cheap Chinese motors and will certainly need a good amount of volts if you want speed but it could go either way on motor heating with 230V with it only being 7nm.
However, If you have the Drive already then you can connect it up and will soon see if it gets hot, for a short period of time this won't damage the motor or drive.


Would you recommend getting a different PSU for the 4 x DM542T drivers? Something with a lower 36V like this for example - https://www.omc-stepperonline.com/power-supply/350w-36v-97a-115230v-switching-power-supply-stepper-motor-cnc-router-kits-s-350-36.html?sort=p.price&order=DESC

Given the application and the fact it's probably not going to be moving very quickly then you will most likely be ok. However I would certainly test the output with a volt meter before connecting to the drive just in case it's putting out more than 48V and if possible adjust the output to it's lowest setting.
If more than 48v then I wouldn't use it as your very close to the limit.


Having looked at the specs of the Nema 34 motor (holding torque 7Nm), it seems like the suggested Driver may be overkill. What would you suggest using instead?

Any of the higher-powered drives allowing 80 - 100Vac will easily handle this job, even with high inductance motor, you'll just have less rpm than a lower inductance motor would provide given the same voltage. But the fact you probably won't need higher rpm's then it won't be a problem.
Then just use a toroidal transformer which gives the output you require. You could actually use a toroidal transformer for the high powered drives provided it's within the drives voltage range. This would lower the output voltage and lessen the motor heating.

[mbridge87]

Ok well, that's a whopping 14mh which is common for Cheap Chinese motors and will certainly need a good amount of volts if you want speed but it could go either way on motor heating with 230V with it only being 7nm.
However, If you have the Drive already then you can connect it up and will soon see if it gets hot, for a short period of time this won't damage the motor or drive.



Given the application and the fact it's probably not going to be moving very quickly then you will most likely be ok. However I would certainly test the output with a volt meter before connecting to the drive just in case it's putting out more than 48V and if possible adjust the output to it's lowest setting.
If more than 48v then I wouldn't use it as your very close to the limit.



Any of the higher-powered drives allowing 80 - 100Vac will easily handle this job, even with high inductance motor, you'll just have less rpm than a lower inductance motor would provide given the same voltage. But the fact you probably won't need higher rpm's then it won't be a problem.
Then just use a toroidal transformer which gives the output you require. You could actually use a toroidal transformer for the high powered drives provided it's within the drives voltage range. This would lower the output voltage and lessen the motor heating.

Thanks for the reply Jazz.

I've not got the driver already but thanks for the advice. I'll buy it and fingers crossed all will be ok.

I'll keep all your other points in mind regarding the PSU.

Thanks again.

Max