How to Enclose VFD for Grinder?

[SteveHGraham]

The other option was to put the motor on the left side. That would have required lots of real estate, because the motor would have had to be pushed back another six or seven inches.

I wanted to put the motor under the platform, but you can imagine the problems that would cause with the belt path.

Here's something weird: when you run the belt backward, it doesn't track. You have to adjust it all over again. Learned that when I was trying to figure out which wire to put where.

I still want some kind of guard on the upper wheel, to keep the belt from hitting me in the face if it snaps. From what I've seen, all you need is a short piece of steel to kill the upward momentum of the belt.

[BadDog]

If you swap belts like I do, you may find that tiny little slot more than a little frustrating, though it may work easier in practice than it looks. One of my favorite features is swapping belts at my whim in seconds. Pull, off, on, release, go. Almost never retrack, but don't reverse either. Sometimes I have a well worn belt of the same grit, and swap it with a fresh and back again depending on what I'm doing at the moment. And you may be much more intimate with your grinder than I with mine, but I've never been hit by a broken belt, and I've broken more than a few being hit wrong by sharp edges or hung in pinch joints. Mostly they just chunk-tear and throw off.

[Magicniner]

No one loved me enough to look at my wiring, so I went to the garage and fired the motor up. It works fine.

On the contrary, everyone loves you enough to make you work for it, you know a finished project has no value if all the answers have been googled for you by others

[SteveHGraham]

If you swap belts like I do, you may find that tiny little slot more than a little frustrating, though it may work easier in practice than it looks. .

This is one of the negatives I had to consider when I decided where to put everything. The belt goes on and off just fine, but I have to exercise care to avoid scraping the grinder with the abrasive. I am hoping to make it slightly easier by moving the grinder a fraction of an inch to the right.

[SteveHGraham]

The ethernet coupling I ordered arrived. It was a few bucks on Ebay. I also received a couple of ethernet cables for the VFD. If you go to Monoprice, you can order ethernet cable and specify the exact footage. Crazy.

The coupling is fantastic. It's exactly the right size for a 3/4" knockout, so it went into the box with no drilling. It's extremely sturdy.

I made an aluminum mount for the VFD control panel, and I mounted it in the only place where it seemed to be out of the way. If I put it by the motor, everything I put on the platform will bang against it. The current location is not ideal, but it works. I put it a little too close to the grinder. The ethernet cable I ordered doesn't bend all that well near the ends, so there's a little pressure on the panel. I may get a different cable. Maybe I'll just put a cable tie on the cable to bend it tight and keep strain off the Hitachi part.

Anyway, I'm happy.

I also found the VFD parameter that shuts the fan off. The fan was running all the time, and I thought it was a bad idea. A fan in a closed box will actually heat the box, and I didn't want that. Also, fan motors don't last forever, so I saw no point in running it perpetually. I set it to turn on when the VFD warms up, which seems like the intelligent move.

I put a plug and receptacle between the motor and VFD box. I had to be able to separate them easily. Now if I have to work on the VFD, I can unplug the motor and leave it on the platform. I don't have to open up the junction box.

[Nelson]

Steve,

It looks really good.

[stevec]

Steve,

" A fan in a closed box will actually heat the box, and I didn't want that" "
" I set it to turn on when the VFD warms up, which seems like the intelligent move."

Sorta sounds sorta sounds a bit contradictory to me.

[SteveHGraham]

Thanks, Nels.

Steve, if you're saying the fan will still contribute heat if it comes on when the VFD is warm, I think that's true, but supposedly (based on knowledge gleaned from the all-knowing Internet) this box is big enough to dissipate heat quickly enough to allow me to use the grinder for long stretches. The idea is that the fan moves heat from the VFD heat sink to the air in the box and then to the box itself. Hopefully the box will radiate heat work well enough to prevent or--and this is the important point--greatly delay the overheating of the VFD. Either way, I win.

If this setup isn't good enough for continuous, all-day grinding, then there must be a time limit based on how long it takes the VFD to overheat and throw errors or whatever. If that's true, then I want it as cold as possible when I start grinding. If it takes 2 hours to quit after starting at 80 degrees, for all I know, it takes 30 minutes to quit after starting at 110 degrees. That would be bad. I don't need it to be able to run all day, but it has to run for at least an hour before getting upset.

The fan was running all the time, even when the VFD was stone cold. While it ran, it generated heat in a confined box, it wasn't cooling anything, and it put wear on the fan motor. It made more sense to have it turn on when the VFD actually needed cooling, like the thermostat on a car cooling system.

I didn't like having the fan run 24/7, when I couldn't be around to watch over it. It got on my nerves.

[spro]

I agree about the fan. It is interesting recalling banks of equipment with their own fans. There was a main supply and fan/filter for that. The individual banks had fans which could cycle off. Problem is, that cutout circuit failed and eventually every bank was filled, every fan was running 24/7 Serious heat comes out of these rows of equipment and serious different ways of HVA to deal with it. It becomes a very complex system as heat exchange used to heat certain areas and cool another adjusting with climate and other variables. But Filter may be in order if it is semi cross thru ventilation.
The other thing I was literally itching to say, is about your cart. I've used them, I have one, they were made by Rubbermaid back in the day. I know how these went together since I assembled etc. Anyway, you have serious weight at one side and no cross bracing. Given that it IS Going to work this way, I suggest that the weight is not directly on the castors.

[SteveHGraham]

I'll keep an eye on it. It's rated for 500 pounds, so I am hopeful.

[spro]

More than that. Just at that side. I wouldn't mention but unlike cast iron, plastic does flex. A quick wedge lift is cutting a 4 X 4 at acute angle. You know this crap but unlike me, you take advice. It is a little thing which can improve stability while using the machine and easily knocked out.