STEPPERS: better lower inductance or lower step angle

paboman

Hi,
I am using Wantai 57BYGH420 and I am happy how they work, they are 1.8 step angle and I would like to increase the resolution using a 0.9 deg stepper.
The only one I was able to find have an inductance of 4.5 instead of 2.5 of the current ones, should I be worried about 80 % more inductance ?

Wantai 57BYGH420
Step Angle 1.8°
Voltage rating: 3.0 V
Current rating: 2.0 A
Resistance: 1.5 Ω ± 10%
Inductance: 2.5 mH ± 20% (1KHz)
Holding Torque 0.9 Nm
6 leads

Datasheet

OMC STEPPERONLINE 23HM22-2804S
Step Angle 0.9°
Voltage rating: 2.5 V
Current rating: 2.8 A
Resistance: 1.0 Ω ± 10%
Inductance: 4.5 mH ± 20% (1KHz)
Holding Torque 1.26 Nm
4 leads

Datasheet

thx!

dc42

Use the motor emf calculator at https://reprapfirmware.org to check whether the higher inductance will limit the movement speed.

paboman

@dc42 the requested speed value is the speed of the carriage or the end effector ?

paboman

Wantai 57BYGH420

OMC STEPPERONLINE 23HM22-2804S

It seems that the torque drop is really high on the 0.9deg stepper, now the question is if the motors can handle the effctor anyway, maybe at a lower speeds...

Any advice is welcome

dc42

@paboman said in STEPPERS: better lower inductance or lower step angle:

@dc42 the requested speed value is the speed of the carriage or the end effector ?

Yes.

Danal

@paboman said in STEPPERS: better lower inductance or lower step angle:

The requested speed value is the speed of the carriage or the end effector ?

Carriage/Effector move the same speed for Cartesian

On Delta, effector speed will vary with the position and type of move... pure Z moves are same carriage/effector, combined moves, particularly where the effector is near the edge of the printable circle, the carriage will move much faster than the effector. So the upper limit of speed of the motor sets the upper limit of the carriage... and the effector "does what it wants".

Below link is a variant on the EMFcalc... set the "Delta Rod Angle" to 45 degrees for Cartesian, or about 20 degrees for most Delta, and you'll see the difference in speed:

http://danalspub.com/EMFcalc/

paboman

@danal
I will try to do some math
thank you.

By the way guys, is 0.9deg steppers something should I try? are the improvments really visible on the prints ?

dc42

@paboman said in STEPPERS: better lower inductance or lower step angle:

@danal
I will try to do some math
thank you.

By the way guys, is 0.9deg steppers something should I try? are the improvements really visible on the prints ?

One a delta, yes because they improve the Z resolution. On a Cartesian or CoreXY, probably not worth it.