# Building up VFD enclosure - attaching to mounting plate



## Clock work (May 18, 2017)

Hello all,

Embarrassingly trivial question... is there a preferred approach in attaching the organs (VFD, contactors, etc) of an enclosure to the mounting plate? Drill/tap or through-bolt? Thanks in advance. 

CW


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## Wreck™Wreck (May 18, 2017)

Many non enclosed components are made with DIN rail mounts, if so buy a piece of rail.
https://en.wikipedia.org/wiki/DIN_rail


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## 4ssss (May 18, 2017)

On my Bridgeport I made a plate that  connected to a 4" square outlet box mounted to the motor, and on my Heavy 1o I made a plate to fit under the original switch. Both plates were drilled and tapped. Here's pics.


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## RJSakowski (May 18, 2017)

Not using through holes is a definite advantage for future repair and maintenance.  I personally would drill and tap.  If the enclosure isn't thick enough to support tapped holes, consider using a backing plate inside the enclosure.


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## bss1 (May 18, 2017)

Member Alan H did a really nice job on a VFD enclosure for his PM1340GT lathe that is documented on the PM forum. He had some pics that may be helpful to you. http://www.hobby-machinist.com/threads/jacobs-vfd-control-system-installed-on-pm1340gt.55294/


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## jbolt (May 18, 2017)

On an enclosure with a backing plate I drill and tap the mounting points. I prefer the contactors, power supplies, terminal blocks etc. to be on DIN rails. Much easier to wire, service and rearrange.

This is the control box I did for the VFD conversion on my PM-1440GT. The VFD and cable gutters are directly mounted to the back plate. Everything else is mounted on DIN rails.


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## Clock work (May 18, 2017)

Thanks all and really nice work in all the photos. I unfortunately went thru all the procurement as I learned about individual organs functionality and ended up without the DIN versions that now need mounting onto the backing plate. Next time The "drill and tap" suggestion tells me it'll be enough to hold the VFD and contactors without ultimately failing due to, say, fan vibration... not great thread engagement, but good enough! 6mm sound good? 

Appreciate everyone's great input. Thanks.


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## jbolt (May 18, 2017)

4mm - 5mm is good enough for the small stuff. Check the VFD manual for the recommended fastener size. 

Most commercial backing plates are steel or phenolic and sufficiently thick enough for drilling and tapping  for most components. I've seen a few import enclosures with plastic backing plates which in that case I would use sheet metal screws for the small stuff and through screws with nuts for heavier items.

For mounting a VFD on a phenolic backing plate I would consider backing up the fasteners with nuts. I have made backing plates out of  aluminum sheet as thin as 1.5mm but in those cases I used self-cinching press nuts on the back so I could remove the screws without the nut dropping out. 2mm and up aluminum is usually good enough for drilling and tapping.

Using through fasteners with nuts can be a real pain if you need remove a component, sometimes requiring removal of the whole assembly.


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## Clock work (May 18, 2017)

jbolt said:


> 4mm - 5mm is good enough for the small stuff. Check the VFD manual for the recommended fastener size.
> 
> 2mm and up aluminum is usually good enough for drilling and tapping.
> 
> Using through fasteners with nuts can be a real pain if you need remove a component, sometimes requiring removal of the whole assembly.



Thank you much. Went down and looked at the contactors and it appears I can hang it off a bolt and tack the bottom down.... though I got wondering about DIN rail adapters and it appears such animals exist at the cost of using up a little more depth. I think I have the room though the VFD itself would be close. My mounting plate is 2.0 mm and I think it's steel.... didn't think to check that. Thank you again.


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## mksj (May 18, 2017)

DIN rails make it convenient to mount components and save one time if individually mounting everything. But I would not go out of your way to add the adapters and additional cost for a simple setup. There is the height of the adapter and the rail, which can add add 1/2-3/4" in overall height. You only have a few things to mount, just drill and tap a back plate and add screws to mount the components. If you are afraid of a screw loosening add some blue Loctite to the threads. I often do simple cabinet installs using direct mount, also for heavy transformers and chokes I usually will use the bolt from the back threaded into the back plate and locking nuts on the top of the plate so it can be removed if needed. I also do this for a star ground post. I like to direct mount rotary disconnect switches that require a lot of torque to turn as opposed to mounting them to the DIN rail. Size of screws are specific to the item being mounted and the weight.
example of installs others have sent me:


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## Clock work (May 18, 2017)

GREAT reply and thanks. Sounds like you've had a bit of practice


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