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Hi I have a pair of 4nm Nema 23's I want to swap on my bottom axis of the router, 4 core CY cable to run off a pair of AM882.
Here's the wiring diagram
Attachment 27439
I want to wire for parallel, guessing 2 wires from the Nema connect to 1 wire in the CY cable but which ones lol?
Could be any wire you want so long as you connect it to the right phase on the drive but here's what I would use.
Wire # 1 = A+ = Red+Blu
Wire #2 = A- = Yel + Blk
Wire #3 = B+ = Wht + Brn
Wire #4 = B- = Org + Grn
The middle one. bypolar parallel
Thanks Jazz, that worked perfectly luckily I twisted the pairs on these motors when I first fitted them so when I swapped the wiring it was super easy to work out the pairs. It worked first time and even both motors went the right way so bonus ;)Quote:
Originally Posted by JAZZCNC
I went from being able to move the dual motor axis at 4m/min to over 15m/min without firing fault protect on the AM882's, 20m/min worked but that screw looked scary lol so I dialed it back.
25m/min and it fired fault protect had to try, 1610 ballscrews with cheap ass mounts but am going to buy a set of proper angular ones from BST.
What controller you using and how many volts. Do you have a ratio on that because at 1:1 that's 2500Rpm.!!Quote:
Originally Posted by Desertboy
it's 1:1 with couplings, I have 80v PSU self build 1kva and AM882's 1 per Nema which can drive up to 8amp's I believe.Quote:
Originally Posted by JAZZCNC
I think the screw whip is just over 2000 rpm for this length so I was surprised it went up to 20m/min.
DDCSV 2.1 I have microsteps set to only 2 at the moment the minimum the AM882's will let you set them from the jumpers.
2*4nm Nema 23's from CNC4you on the bottom axis, 1*3nm on the gantry both fire fault protects when I go over 20m/min but under seem to work but I would never run then that fast lol.
Rest of the machine is not up to the job for sure.
Are those the 4nm NEMA 23s from CNC4YOU with a 4.2 amp current limit? What have you got the AM882 set to?
Yes they are, and now you ask lol I used the AM882 autotune function on the last motors I just replaced not actually "Autotuned" the new motors so they aren't even close to set up correctly.Quote:
Originally Posted by AndyUK
Last motors were only 1.8nm so must be out and I did a cut for 30 mins and the motors were cool to touch, need to tune them in to get best performance but motors are stronger than machine lol.
I only built the machine out of 4590 heavy duty extrusion it's not steel.
Your asking for trouble running at the drives Max voltage. You will damage them at some point if your running at high feeds and happen to catch the mains at a peak the back EMF will fry them.!Quote:
Originally Posted by Desertboy
They will run like a grumpy bear at 2 x turn them up to 8x and they will run much smoother, you'll lose a little torque but will run much nicer.Quote:
Originally Posted by Desertboy
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.Quote:
Originally Posted by AndyUK
I'll try that in a minute, thanks.Quote:
Originally Posted by JAZZCNC
PSU test's at 72v without load ~68v with load with home supply when I try it at work I get 78v without load and around 70v with load, it's a Toroidal transformer.
That really confused me originally but power is far from clean.
When Maplins went bankrupt they were half price so I bought 2 both 1kva.
I was aware that going slightly over would just lead to more cooling requirements, but didn't realize they were quite so lenient.Quote:
Originally Posted by 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?
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.Quote:
Originally Posted by AndyUK
It's something that I've not done yet but is on my list. Does it suggest a current setting for you?Quote:
Originally Posted by Desertboy
Most data sheets nearly always quote peak ratings, so if doesn't state RMS always go with peak.Quote:
Originally Posted by AndyUK
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)Quote:
Originally Posted by AndyUK
#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
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.Quote:
Originally Posted by AndyUK
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
Yeah there's a strange hiss and squealing that changes pitch even when the notes aren't doing anything. I just assumed it was the drivers being weird...!Quote:
Originally Posted by JAZZCNC
Yeah definitely something I will look at over the weekend.
Tuned my all my motors last night and manually set the currents using Protuner. Much happier machine now, the X axis has gone from stalling at 8m/min to being able to do 15m/min without flinching. The Y can do 20m/min, but I've set both X and Y back down to 10m/min for general use.
Still getting some quiet hissing and squealing, although it seems to be emanating from the motor drivers not the motors themselves. Is this something I need to keep an eye on?
Nothing to worry about it's quite normal to get quiet hiss, often it only happens when stood still and it's the recirc circuit lowering the current.Quote:
Originally Posted by AndyUK
Surprising isn't it how much difference the tuning makes..:thumsup:
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.Quote:
Originally Posted by JAZZCNC
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.