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-dut...robot-arm.html

Large driver for slider - https://www.omc-stepperonline.com/di...ice&order=DESC

PSU - https://www.omc-stepperonline.com/35...0Router%20Kits

4 of these drivers - https://www.omc-stepperonline.com/di...tepper%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/di...ice&order=DESC

Alternate motor - FM86150SJD04-P(2-phase).pdf

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

[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-3000....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 – Nema 34 motor FM86128SJT03-FSL120.pdf
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/po...ice&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.