Control Panel Circuit Protection

[NickB]

Looking for some advice on protecting the components in the control panel. I am open to any suggestions and input because I have reached a bump in the road with the electrical aspect of this project. I have primarily been looking at adding a fuse to the input of each device. I am looking at feeding 208V single phase to the three axis power supplies and the included Meanwell RD-35B power supply for the Acorn board. I will then be feeding the VFD with 208V 3-Phase.

Components that I am using:

- Automation Direct DURApulse GS23-25PO VFD
https://www.automationdirect.com/adc/sh ... /gs23-25p0

- Meanwell RD-35B Power Supply
https://meanwell-ps.com/products/rd-35b

- Stepper Online NEMA34 Closed Loop Stepper Kit
https://www.omc-stepperonline.com/ts-se ... lts120-v41

- Power supply for each axis motor (included in the kit)
https://www.omc-stepperonline.com/350w- ... s-s-350-60

If I can provide anymore info please let me know. I have been at a standstill with making progress with the remaining electrical tasks that I have to do.

Disregard the mess at the bottom of the control panel, that will all be taken care of. If you see any other issues please let me know this is a first time build and way out of my comfort zone and knowledge base.

[ShawnM]

The cabinet is already tight with all your components so you'll probably need to move some things around to be able to add in some DIN rail circuit breakers. You'll want a circuit breaker on each of the 5 components you mentioned. All 4 power supplies and the VFD. You topic title says "fusing" but I assume you meant circuit breakers, yes? You can have the Acorn supply a signal to a contactor to power up all the components at startup.

[NickB]

Thanks Shawn and I was not sure whether using fuses or circuit breakers would be better (title shows some of my lack of knowledge and inexperience but I am trying my best with it all). The power will be coming from a 30A 208V feed from the circuit breaker that goes into a knife switch and then from there is distributed, if I understood the electrician correctly. Could the three power supplies be swapped out for one supply that could handle all three motors and if so would there be any advantage or disadvantage (I am thinking for conserving space). What is the best way to size a circuit breaker for each component?

[ShawnM]

Hi Nick, you can also turn the power supplies on their side, vertically, and save space. Just be mindful about cooling. Not to close and the fan toward the bottom, should stay cool and save space. You can go either way with the power supplies, one or 3, you just have to make sure you have enough current for the motors full load amperage X3. And then enough headroom on the voltage side for back voltage when the motors rapidly slow or stop.

I'm not a fan of Gecko drives but they have some good white papers on power supply basics that will make a good read for you. See this webpage:

https://www.geckodrive.com/support/power-supply-basics/

A circuit breaker for each component is best. Just determine the max load for each device and and buy a circuit breaker to match or the next available size up . Like if you need 8 amps of protection on a circuit and can't find a 8A breaker you can easily buy a 10A circuit breaker.

Last question, is your backplane in the cabinet metal or plastic? It need to be metal, plastic is a very bad idea for a backplane and cause noise issues.

[NickB]

Hi Shawn, thank you for that information, its very helpful. The backplane is metal. What would your recommendation be for grounding the cabinet? I have a busbar that I plan on running the ground from each device to, but still unsure of the best way to ground the cabinet itself. Would I run the ground from the breaker panel to the body of the cabinet and then from there a wire to my bus bar?

[cncsnw]

Yes, that is most typical.

Bring a ground wire in along with your AC service lines, and land it on a panel/cabinet ground lug adjacent to where the incoming power is connected. Then run a wire from there to whatever terminal block you want to use to collect the rest of your grounds.

[ShawnM]

That's exactly how I do it. Ground the cabinet at its ground lug with the incoming ground from my 4 conductor main power wire and then run a jumper over to a copper ground bus bar where I ground all my components to. I run a 4 conductor, 220v line in from my power panel so I an have 220 for the machine itself and I also install a 4 gang, 110v junction box on the machine frame to plug in misc hand tool as I sometime use the table to sand on or do other work with hand tool that require 110v. This way I don't need to run extension cords anywhere.