Wiring an 8 wire Nema to 4 core CY cable to an AM882

[AndyUK]

Andy, just want to clear something up just in case you or others think the drives current rating is a must not exceed the limit or will break.! . . . They are not limited to 4.2a you can actually run them higher and you won't damage them. It's not recommended because you will over time shorten their life because they will run hotter and the gains will be limited so not worth doing. But you won't kill them running a little higher current.

I was aware that going slightly over would just lead to more cooling requirements, but didn't realize they were quite so lenient.

Let's explore this a bit though; those 4nm Nema23s from CNC4YOU just have "current" listed in the datasheet as 4A. Now is that likely to be a peak or RMS current suggestion?

My EM806 drivers, essentially the same as Desertboy's, have a current table with Peak and RMS, what settings would you use for these motors?

I'm kinda surprised we're talking about this machine being able to reach 20m/min, I'm stalling at half that!

[Desertboy]

I was aware that going slightly over would just lead to more cooling requirements, but didn't realize they were quite so lenient.

Let's explore this a bit though; those 4nm Nema23s from CNC4YOU just have "current" listed in the datasheet as 4A. Now is that likely to be a peak or RMS current suggestion?

My EM806 drivers, essentially the same as Desertboy's, have a current table with Peak and RMS, what settings would you use for these motors?

I'm kinda surprised we're talking about this machine being able to reach 20m/min, I'm stalling at half that!

They should have an autotune function like the AM882's have a look in the manual, I used it with my first motors and it really did seem to work.

[AndyUK]

They should have an autotune function like the AM882's have a look in the manual, I used it with my first motors and it really did seem to work.

It's something that I've not done yet but is on my list. Does it suggest a current setting for you?

[JAZZCNC]

It's something that I've not done yet but is on my list. Does it suggest a current setting for you?

No, it doesn't, you still have to set the current using the Dip switches or can connect to drives and use software to set them more accurately in 0.1a increments.

The autotune can make a big difference and it's certainly something you should do. Do your motors Hiss or squeal.? . . . If so they will stop after Autotune

[JAZZCNC]

Let's explore this a bit though; those 4nm Nema23s from CNC4YOU just have "current" listed in the datasheet as 4A. Now is that likely to be a peak or RMS current suggestion?

My EM806 drivers, essentially the same as Desertboy's, have a current table with Peak and RMS, what settings would you use for these motors?

Most data sheets nearly always quote peak ratings, so if doesn't state RMS always go with peak.

I'm kinda surprised we're talking about this machine being able to reach 20m/min, I'm stalling at half that!

Couple of reason why he'll be getting that speed. If he really is because 2000rpm is high for a stepper.? (Have you checked the machines moving correct distance.? If steps Per is wrong you'll get false reading)

#1 He's only running at 400 Ms so will have more torque but the motors will be running very rough.
# 2 He's running well above 70vdc and close to 80V

[Desertboy]

Most data sheets nearly always quote peak ratings, so if doesn't state RMS always go with peak.



Couple of reason why he'll be getting that speed. If he really is because 2000rpm is high for a stepper.? (Have you checked the machines moving correct distance.? If steps Per is wrong you'll get false reading)

#1 He's only running at 400 Ms so will have more torque but the motors will be running very rough.
# 2 He's running well above 70vdc and close to 80V

I'm running at 68-70v with load from the stepper a couple of volts higher without, the steps are setup right dimensions spot on, 1:1 coupling on all axis, now I turned on 8 microsteps it faults at 20m/min but dialed back to 15m/min and it's very happy and does seems smoother.

I have the cutting speed set to 8m/min seems to make nice parts 2mm cuts, might try it at 10m/min.

Only doing wood if I ever do aluminium I'll dial the speed right back and only cut to the sides on the machine where it's strongest.