3 phase vs 2 phase nema 34

[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.

[JAZZCNC]

This is the spec of the 3-phase Nema 34 motor I currently have for the slider – Nema 34 motor FM86128SJT03-FSL120.pdf

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/po...ice&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