Kstep VB question?

Moderators: TomKerekes, dynomotion

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inwu
Posts: 7
Joined: Fri May 24, 2019 5:37 pm

Kstep VB question?

Post by inwu » Tue May 28, 2019 10:36 pm

I have done some research on my custom-made CNC system. I found out they connect two 36V 9.7A power supply to KStep J1 input. Although J1 has two VB input, but I assume they are actually shorted on the board. Will this cause any problem?

The KStep actually drive 4 step motors. Two are wantai 57BYGH115-003B (3A) and the other two are 85BYGH450C-012B (3.5A). I assume the maximum the 36V they will need is 3 x 2 + 3.5 x2 =13A. That's why they join two 9.7A power supply to do it.

Any suggestion please?

Tony

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TomKerekes
Posts: 615
Joined: Mon Dec 04, 2017 1:49 am

Re: Kstep VB question?

Post by TomKerekes » Wed May 29, 2019 1:33 am

Hi Tony,
I have done some research on my custom-made CNC system. I found out they connect two 36V 9.7A power supply to KStep J1 input. Although J1 has two VB input, but I assume they are actually shorted on the board. Will this cause any problem?
Yes the two VB terminals are connected to the same power plane on the board. It usually isn't a good idea to connect two regulated power supplies in parallel. If the voltages are not set exactly the same they may fight each other and sink/source huge currents.
The KStep actually drive 4 step motors. Two are wantai 57BYGH115-003B (3A) and the other two are 85BYGH450C-012B (3.5A). I assume the maximum the 36V they will need is 3 x 2 + 3.5 x2 =13A. That's why they join two 9.7A power supply to do it.
That's not quite how it works. Please see this wiki article.
Regards,

Tom Kerekes
Dynomotion, Inc.

inwu
Posts: 7
Joined: Fri May 24, 2019 5:37 pm

Re: Kstep VB question?

Post by inwu » Wed May 29, 2019 6:55 pm

Hi Tom,

Thanks for the help. I really need to do something about the power supply!

Tony

Moray
Posts: 121
Joined: Thu Apr 26, 2018 10:16 pm

Re: Kstep VB question?

Post by Moray » Fri May 31, 2019 4:25 pm

inwu wrote:
Wed May 29, 2019 6:55 pm
Hi Tom,

Thanks for the help. I really need to do something about the power supply!

Tony
It's worth mentioning that some regulated supplies will run quite happily in parallel, whereas others will quite quickly fault out. Those that fault out, are also the ones likely to give issues with faulting during fast deceleration where the stepper driver(s) are dumping energy back into the power supply.

However given the current rating of your motors, a single 9.7A power supply should be ample.

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