3 phase vs 2 phase nema 34

**mbridge87** · 17-08-2020

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** · 17-08-2020

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** · 17-08-2020

Originally Posted by 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.!!

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** · 17-08-2020

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?

**JAZZCNC** · 17-08-2020

Originally Posted by mbridge87

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.

**mbridge87** · 18-08-2020

Originally Posted by JAZZCNC

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.

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** · 22-08-2020

Originally Posted by JAZZCNC

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.

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** · 22-08-2020

Originally Posted by mbridge87

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.