DIY CNC 2

On your PSU: I have used a similar PSU on a similar project and it worked great. dbtayl's notes on PSU are correct, but another way to success is to use an oversized PSU. According to the specs you seem to be doing so.

So based upon what I'm using you don't think I need to swap out for a different PSU that has said protections?

CAT6A should do if you make sure it is multi-stranded. On a lot of cheap network cable each wire is solid = will break soon if it has to flex a lot. Breaking wires between your motors and drives can fry your drives. Just something to keep in mind.

I feel like this would do good.

Logthor wrote:

So based upon what I'm using you don't think I need to swap out for a different PSU that has said protections?
 

How many stepper drives? If 3, then we're looking at 4 amps per motor * 3 = 12 amps total. Your stepper drives will draw less than that. Now, cheap PSUs tend to be overly optimistic with their current rating. I think your PSUs are easily sized double what these specs require. Which I think is a good plan. Go for it. I would buy that.

Your twisted pair cable looks great. I was just coming back with a suggestion 18 Gauge 4 Conductor Shielded when I noticed your post.

How many stepper drives? If 3, then we're looking at 4 amps per motor * 3 = 12 amps total. Your stepper drives will draw less than that. Now, cheap PSUs tend to be overly optimistic with their current rating. I think your PSUs are easily sized double what these specs require. Which I think is a good plan. Go for it. I would buy that.
 
Are you sure it is 4 amps per motor? I thought that at most it'll draw 2 amps between the two windings (2.8 amps if it is peak). Sounds like a plan regardless. I was thinking I might just use a TL431 on the main bus and have it send all back voltage to a large resistor.

Logthor wrote:

Are you sure it is 4 amps per motor?

 

4 amps per motor... I was thinking worst case. In practice you won't hit that.

A TL431 Precision Programmable Reference by itself won't handle the current. It will need some form of power transistor to handle the current. My little home-built cnc mill I had for a while had simply a cheap switching PSU powering 3 stepper drives with no additional protections. If a person had to add something I would connect  a 35V 10,000 uF capacitor to the DC bus. This adds cushion to even out short duration voltage spikes from decelerating motors.

TL431 was/is some type of low current voltage regulator of reference or ... been over 30 years, so it can not send anything to big resistors.
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Start over:
-get some cheap drives, the so called "TB6600" that do not use the TB6600 chip are very good as they are the cheapest boxed drives, i have probably over 40 in daily use
-Get a MeanWell or Delta power supply, 24V (no, not 36V nor 48V) and 200W or 8.something amps, it is more than enough for 4 or 5 or 6 drives at full current of 3.5A (they are rated at 4.5 or 5A online), never mind the math for now.
-get a used PC with parallel port, or buy an add on parallel port
-wire the drives to the PC, with no BOB (your choice, i never use them)
-start making chips.
Oh cr@p, i just went back and :
-forget the parallel port
-those drives are fine, i have them for over two years.

So much advice already but a coupe of pointers including from some gecko docs I read years ago.
1. Doubling the motor voltage almost quadruples available torque
2. Any power supply for CNC can be overrated by about 40% so for 3 or 4 x 2 amp motors a 5 amp power supply is plenty
3, If a drive does not have a max temperature spec, be guided by the temperature the windings start to melt which is typically around 130 deg C but your motors are silent on that too. 80-100 deg C is fine

I always run 48 volts and sometimes as high as 90 volts but on a small machine I might consider 36 volts depending on manufacturers recommendations. 24 volts leaves too much available torque on the table.
I would prefer you to use seperate power supplies with the 7i96
Meanwell MDR-10-5 for logic (5v)
Meanwell MDR-60-24 for field power (24v) MDR-40-24 is Ok too.
Meanwell NDR-240-48 (48 volts) for motors but a LRS-350-48 (7 amps) might be cheaper and is a popular choice.