kbdf-27d

T

tommywoh

Joined
Oct 17, 2014
Messages
43
is it safe for me to use a kbdf vfd for a grinder without an enclosure ? if not is there any way to make a cheap and efficient enclosure for it ?
 
THe KBDF are great VFDs I have them on some CNC mills but yes you will need to put it in a enclosure or in another room where there will not be grinding dust. The KBDF is a very programmable vfd and you would not use these functions for a grinder install. I personally would spend the the fee extra bucks for a KBAC-27d. If you have any questions I would be glade to help.

Brett Mathews
Esteem Grinders
 
My solution was to mount it in a dry box. Not very elegant, but it works. Given the choice I would have bought the KBAC-27d. I bought mine on eBay and was in a hurry to get my grinder up and running.



 
If you mount it in a dry box, you may need some ventilation to get rid of heat. I drilled holes in the box and covered them with cheese cloth on the inside. Allows excess heat to escape and the cheese cloth can be replaced when dirty.

Tim
 
I purchased a cheap Chinese VFD on ebay for $120 shipped - it's an open case like the KBDF. I mounted VFD at back of grinder stand and put filters over the air intakes to allow some air flow, but still stop dust. This allows seeing the display while changing speeds, START/STOP etc. I mounted a OFF/ON, START/STOP, and a 10K pot on front of stand for ease of control.

Ken H>
 
Tommy, you'll still need some ventilation holes for the heat to move out of box. Just an enclosed box with no vents will just move heat around inside the box, not provide any real cooling for the VFD.

Ken
 
what I meant was cutting an opening in the dry box and placing a fan pointing out on that opening so it can suck hot air inside the box and blow it out
 
IF the fan is sucking air/heat out, there needs to be a place for air to come in so the air can flow. Without an inlet point, the fan is trying to pull a vacuum in the box and very little air/heat movement will result. That was my plan at first, to put my VFD inside a box, then as I thought about it more, I realized I'd still need inlet filters, so why not just put the filters over the existing air inlets and save on mounting a box?

Ken H>
 
I just took some good type A/C filters and cut sections required to fit VFD enclosure opens and "fastened" them on. Depending on shape/location of air inlets determines the best/easiest method of fastening. I just taped my filters for a trial run. So far, it seems to be doing the job. The VFD enclosure has a small fan blowing out from enclosure.

I would use a pretty fine type filter to be sure no metal dust got inside enclosure. The VFD I used was only $116 shipped, so it's not the expensive type at all.

Ken H>
 
Hey Ken how many hours or actual use would you say have on that Chinese vfd ? All the guys I know who have tried to use them over the years had them fail with in 6-12 months with moderate use a couple where D.O.A. They where not happy campers as they had to ship them back to china and wait for new ones to be sent. From my understanding the ssr's used in them are very poor are not up to the task of what most of use them for. (Machine tools)
Honestly to me the risk is just to big and the savings is not enough for me to recommend any body using them. Ken may have lucky and got a good one but it would be the one of the first one I have heard of yet. LOL
By the way the KB are USA made and they have super great customer service.

Brett Mathews
 
The Chinese VFD might fail in a few months, just no way to tell. There have been several folks using them in small desktop tyep CNC mills. These folks fall into two groups, either they're "great VFD" or "worst thing going and don't last". I've not been able to determine just how many actual folks are in each group. I know of one VFD personally used on a CNC mill for the last yr and has been good. The vendor I ordered from is USA based and "says" he acts as warranty help. Don't know how it will work out. "IF" ("when"??) it does fail, I'll decide which to order as replacement. I've got a Teco VFD (USA made?) drive on my lathe - perhaps I should have used one of those, but we'll see.

Ken H>
 
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