# VFD box wiring with diagram - Help



## Steve ATL (Feb 8, 2021)

I am putting together my first CNC, but need help with the wiring for the control box for the VFD to make sure it will work and I don't blow my self up...

This will be coming from 240v (30amp) 1 phase power (L6-30P connector). 
Note: Since the pins from the connector are 120,120, ground - I made the layout according

Can anyone offer any assistance or guidance?

I have included the diagram and the PDF I made

Thank You,

Steve


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## TimPa (Jan 4, 2011)

That looks fine, assuming that you have verified all of the power requirements for each device. take care when making your connections, with 15 amp protection, you should use 14 gauge solid or stranded wire. stranded flexes better for this typ of wiring. follow the manufacturer power up sequence if there is one.

others may have thoughts i may have missed... good luck - keep us informed.


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## ger21 (Feb 10, 2019)

I don't see any reason to use fuses in front of the breaker, as they both serve the same purpose?

Also, I wouldn't use an E Stop to kill power the VFD.
It's not good for the VFD, and it won't stop the spindle from spinning. It could spin for another 20-30 seconds or more.
A better choice would be to wire the Estop to an input on the VFD to issue a "Stop" command, which would stop the spindle much faster.


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## Steve ATL (Feb 8, 2021)

Ger,
Good point on the fuses, i was just being over careful as I have never wired anything up like this.. I will have to look at the booklet on the VFD to see what input I could use.

Does everything else look good, so I don't blow myself up?


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## difalkner (Jan 3, 2012)

Welcome to the forum, Steve! I was also going to point out the fuses in front of the breakers but that's been discussed. The other thing I would point out has also been discussed, don't put the E-stop in front of the VFD. It's far better to do what Gerry said and have the VFD issue a 'stop' command.

David

PS - we do like photos, so show us your build whenever you're ready


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## TimPa (Jan 4, 2011)

"A better choice would be to wire the Estop to an input on the VFD to issue a "Stop" command, which would stop the spindle much faster"

with all do respects... an "emergency stop", being a safety control, _should not _be integrated into a software environment where it can be caught up in a software loop and rendered useless. E Stops should remain as a hard-wired electrical disconnect. now, if you wanted to wire in another _spindle stop_ button to be software controlled - have at it...


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## Steve ATL (Feb 8, 2021)

Thank you to all for the advice and great pointers....
With regards to the E-Stop I thought of having 2 of them, one on the VFD cabinet (either connected directly to the VFD if I can or to a relay that sends power to the VFD)

I am in the process of waiting for parts to show up (Avid CNC parts, doing my own frame from 8020 heavy).

- Water cooled 2.2 kw spindle and VFD (I feel very comfortable with water cooling done high end computers with it for over 10 years)

For the control and motors still trying to decide but was leaning to Nema 34 size Teknic ClearPath CPM-SDK-3421S-ELN as I may want to extend this from a 4x4 to a 4x8 and kind of torn between the Masso and Centroid Acron.

This is really going to be a hobby for now, but with retirement not that far away, I may be more serous about it to keep me busy.
"For better or worse, just not for lunch"

Open to idea's and thoughts..

Thanks Again,

Steve


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## difalkner (Jan 3, 2012)

My build is now a bit dated (4 years ago) but there are lots of photos and discussions if you want to check it out - www.routerforums.com/cnc-routing/97721-2nd-build-first-cnc-router.html

David


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## old55 (Aug 11, 2013)

Welcome to the forum Steve.


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## ger21 (Feb 10, 2019)

TimPa said:


> with all do respects... an "emergency stop", being a safety control, _should not _be integrated into a software environment where it can be caught up in a software loop and rendered useless.


I never said anything about software controlling the Estop. I wouldn't recommend that either.
I've run a couple $150,000 industrial routers, and they do not cut power to the VFD with an Estop. Mainly because that does not stop the spindle from spinning.

Steve, the guys that gave you advice on CNC Zone are far more knowledgeable than me, but basically gave the same advice.

There are a lot of ways to stop the spindle on an Estop that are better than killing the power to the VFD.


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## TimPa (Jan 4, 2011)

i apologize, i must have misinterpreted this comment "... to an input on the VFD to issue a "Stop" command". 

maybe the other set of contacts on the E Stop switch could be wired to continue power to the spindle VFD for a graceful shutdown.


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## fmustang1981 (Apr 5, 2021)

Hello guys. I need a little help from experienced professionals. My inverter is not working for a reason I don't understand. I took it apart because I thought there was something wrong inside, but it turned out that wasn't the problem. Given that this was the most reliable part of my system, consisting of automation electronic parts with warranty, I still think that the problem is somewhere in the circuit, but I can not find the exact location of the failure. Since I am not an expert in this field and this is my first job, it would be cool if you could tell me where problems usually occur in such systems.


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## old55 (Aug 11, 2013)

Welcome to the forum @fmustang1981


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