Thread: Electrical Enclosure Queries

I have three VFDs, a 110v transformer and a magnetic contactor or two that I need to house in a tidy fashion. So far I've had the mill's main motor 2.2kw VFD squatting in shabby fashion behind the mill on the floor.

I had picked up a steel enclosure with the intention of cutting a porthole in the door into which an acrylic window would be fixed but a window large enough to view all three VFD displays wouldn't leave much door. So then after visiting Rod M and seeing the molded plastic enclosures Rod uses on his CNC creations, I found an Australian seller of Korean DSE enclosures on Ebay. I then found the manufacturer's website where it was possible to download CAD files showing the fully dimensioned drawing of the enclosure I though best suited my requirements.

http://www.ebay.com.au/itm/321080734...695%26_rdc%3D1

This enclosure has a transparent cover.

I have a few questions. The VFDs I have are TECO FM50s. I was hoping to mount then on DIN rails but I'm buggered if I can see how that can be done without some additional hardware. Any ideas?

Then there's ventilation. I intended to mount some sort of computer-ish fan in the enclosure. Is there something better? And what about filtration of the ventilation air? My shed's open eaves ensure an even distribution of dust and grit throughout the space. I've seen installations where large holes have been cut through the sides but with my fondness for cast iron and my intention to mount the enclosure on the wall behind the mill, holes wouldn't be too clever.

I won't be using the VFD's frequency controls which will be set at 50Hz. I plan to have a couple of switches mounted on the outside of the enclosure. One main power, the other for motor reverse.

Can anyone think of something I may have glossed over regarding the suitability of the enclosure before it hit the "buy it now" button?

BT

Fans are available from various sources that have a filter. Or separate filters like this:

Altronics - F1024 80mm Plastic Fan Guard With Filter

You can also buy filtered vents. (or just use the above item as a vent.

Large enclosures often come with or have available as a separate item a "mounting pan" which normally attaches on four studs located internally in the enclosure allowing you to mount the contents of the enclosure without drilling through the back and reducing the IP Rating of the enclosure.

In the case of the one you have linked to, the raised circular "pins" with the holes in the middle (for lack of a better word) around the perimeter of the inside of the enclosure are intended to accept a self tapping screw to enable you to mount equipment without penetrating the enclosure. However they will probably not handle a lot of weight.

DIN rail is also available from a number of sources including Altronics in the link above.

I always avoid drilling holes in the top of the enclosure as it is usually easier for dirt or water to fall in through the top than the sides or bottom.

Hi BT,

Hmmm.... I don't see a base plate? There is usually an internal steel plate that bolts to the base...

I'd recommend you contact NHP in perth and get a quote on a suitable CVS enclosure. ( if you want to go up market you could go Rittal? )

http://www.nhp.com.au

mounting enclosure manufacturer ( I see that you can download catalogues from that site )

Regards
Ray

I use a 12V computer fan to vent the enclosure for the 1.5kW VSD for my Hercus.
The fan is wired via a 240/12V adapter in parallel to the power supply to the VFD.

For the number of units you have I would suggest a 240V fan like this
Altronics - F1028 120mm 240VAC Sleeve Bearing Slimline Fan
Being 240V it eliminates the need for an adapter.
I have one of these fans on my compressor enclosure and it has plenty of air flow especially if you want to fit some sort of filter which will restrict air flow.

Hi BT,

I wouldn't worry about a fan, the TECO FM50 comes in a version already in an enclosure and has an external heatsink, so long as you use a metal enclosure ( of reasonable size ) the enclosure will act as sufficient heatsinking especially given the sort of duty cycle you would be running...


Teco FM50's showing the external heatsink.

A fan just provides a means for dust and crap to get in, it's better to make the heatsink external, and use convection cooling.

For bigger drives running 24x7 we have used water cooling, heat exchangers and all sorts of complex solutions to remove heat, but for small drives like this with very low duty cycles heating is pretty much a non event, so long as the heatsinking is external.

Regards
Ray

hi bob,
do you have the manual for that teco drive. It will recommend how to mount it.
Having the heatsink. If needed. Out side the drive inclosure can save all sorts of
problems but may require a fan and shroud of its own. I think though except
maybe during real hot weather a roomy enclosure with a filltered vent should
survive.