Re: Hybrid stepper motor.
Re: Hybrid stepper motor.
Hi,
no doubt there are many high torque 23 size motors but they also have high inductance and you need to avoid them.
All steppers lose torque the faster they go. Winding inductance is the primary measure of how bad that torque degradation will be.
A 6mH motor might have as little as 5-10% of its rated holding torque at 1000rpm whereas a 1-1.5mH motor might have as much as 40-50%
at 1000rpm.
By all means find a motor with more torque but reject anything over 2mH or your new motor will start losing steps or stalling at speed.
The classic way to overcome winding inductance is to use the highest voltage driver and power supply you can find. At the current time the
market leaders are 80VDC capable.......you should aim for 80VDC drivers and supply.
Craig
Re: Hybrid stepper motor.
Re: Hybrid stepper motor.
Quote:
Originally Posted by
Pugman1
Thanks for the reply’s
Finding something high torque (say 425oz- 570oz) with an inductance of less than 2.5mh is pretty much impossible.
My 570oz nema23 from the uk are 3mh (the uk has crap!). Importing the Automation tech ones would have cost too much.
https://www.automationtechnologiesin...3h2100-50-4bm/
To counteract my inductance I run them on 60Vdc with 80vmax drivers. They run awesome and are quiet.
Anything above 2mh run on 60Vdc it makes a big difference but. Go no more than an inductance of 3mh.
Re: Hybrid stepper motor.
In the scope of this discussion, I've a serious dilema :
I'm building a Router CNC, and planned to buy 4 NEMA34 closed loop steppers ... I targetted this model : https://www.befr.ebay.be/itm/1Axis-N...MAAOSwTm9dUqyN
5Nm Torque and 2mH inductance
But at this moment, there are sale on the 9Nm and the 12Nm version:
for the same price, i can get the 12Nm version but has and inductance of 8.4mH, or for 10% less I can get the 9Nm version with an inductance of 4.2Nm
In my design, i expected 5Nm ok for my need (two steppers config for the Y, one for the X and one for the Z)
PS: expected power supply are 350W 60VDC (one per stepper)
What would you advice ?
Re: Hybrid stepper motor.
Hi,
I personally would get the low inductance motor.
May I suggest that you compare, preferably overlay the three speed/torque diagrams and I'll bet you that the 5Nm motor
has more torque at 1000 rpm than either of the 'apparently' stronger motors, that's what low inductance gives you.
I think your power supply, at one per stepper will be more than adequate, but if you can get 72VDC or 80VDC assuming your drivers
are rated to 80VDC they are preferred. It gives you more top end speed.
Craig
Re: Hybrid stepper motor.
Quote:
Originally Posted by
joeavaerage
Hi,
I personally would get the low inductance motor.
May I suggest that you compare, preferably overlay the three speed/torque diagrams and I'll bet you that the 5Nm motor
has more torque at 1000 rpm than either of the 'apparently' stronger motors, that's what low inductance gives you.
I think your power supply, at one per stepper will be more than adequate, but if you can get 72VDC or 80VDC assuming your drivers
are rated to 80VDC they are preferred. It gives you more top end speed.
Craig
Actually, the drivers are rated to 100VDC ... but it is quite hard to find such power supply