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VFD and 3-phase motor on drill press

mm08822

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sounds like this is new old news:

that said I'm all for breakers that don't annoy me.
Conceptually, I agree. But delivering against what has just become a defined standard (albeit, currently optional for now), maybe, maybe not.

Sq D may have just filtered out "noise" above a certain frequency. The gfci specs all seem to mention operation on 60 Hz systems. That could easily have opened the door to a narrower scope of possible protection while meeting the current spec in place at that time.

The new supplement in UL 943 has a range from 50 hz - 10Khz. Leakage current at the higher hz appears to have less health risk than at 60 as shown in the UL chart for required trip values.
 
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rattle_snake

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Decided to take the 220V input VFD off this drill press for another project and put in a 2.2kw 110 VAC input one in it's place. Then it can go anywhere and plug in to a normal receptacle. This way is to spend more time and money to get to the same place as before, which I am quite good at.

I decided to move the power switch from the VFD's j-box back to the head of the press. It has a standard sized switch box already.
I had tossed the power cord, which didn't matter as it was undersized for the new motor, at 110V. Same for the original power switch. 2hp is roughly 1.5 kW so about 14 amps and needs at least 14 gauge. I found a 9', 14 ga whip at HD, and also bought a short length of 14/3 SOOW. The on/off switch I had bought is rated for 2 hp, 15 amps @ 110v. Hogged out the holes in the lid for the larger wiring. Used a clamp style grommet to strain relief the new power cord in the old hole. Used some larger p-clamps to secure the wiring.
_2XTAvQK5NWr8VmLKXKhw=w683-h911-s-no-gm?authuser=1.jpg

I try to pre-wire everything on the bench and not wire things in place. This only works if you have a plan and know what you are trying to accomplish, and how to do it. Then you can just do it, and install it. It was difficult to get two ring terminals on the safety switch so I built in the provisions for the light into the VFD lead. Light is always on if main power is on.
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Don't have to put these VFDs that require a box in a box. but they should be. Otherwise you have wiring like this. Yes it could be strain relieved and safer.
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Found a suitable sized plastic j-box and started on modification to make it into a VFD vented enclosure.
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Air inlet at the bottom below the fans
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Slot at the top for exhaust
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Decided to go with wiring out the back instead of the bottom. I think it worked out better.
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Did a poor but quick job of making an air dam to force the exhaust air out of the enclosure after it leaves the heat sink. A piece of bent metal would be better looking.
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Very carefully made a square hole for the control panel. There is no lip, only a slight taper. Have to sneak up on friction fit, get only one try.
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Could have made a vent shroud for exhaust outlet. Motor wiring is still 18 ga, which is sufficient for 2hp/1.5kW @ 220 VAC, 7 amps.
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I needed a switch box spacer to leave the wiring as-is under the belt lid. So I bought a pair of safety switch boxes and cut one up in the table saw to make a perfect spacer, complete with a lip on the front. Longer hardware and it worked out pretty decent. Switch is rated for 2hp/ 15 amps @ 110 VAC.
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Programmed the VFD and tested it out. For whatever reason this VFD doesn't turn the motor below about 22 Hz, which is fine. Can go back and look into low freq torque boost feature, but for now set min freq to 25 and rock on.
hjk6NKTrXPokyA8CJc7xA=w683-h911-s-no-gm?authuser=1.jpg

Added and exhaust stack to the lid in place of the carburetor.
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manwithtools

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Did a poor but quick job of making an air dam to force the exhaust air out of the enclosure after it leaves the heat sink. A piece of bent metal would be better looking.
Get that foam out of that enclosure ASAP! VFD's rely on airflow all around them for proper cooling, not just the heat sink.
 

whateg01

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doo dah, kansas, usa
Get that foam out of that enclosure ASAP! VFD's rely on airflow all around them for proper cooling, not just the heat sink.
I was thinking as I looked at the pictures that maybe this vfd will never be worked hard enough to get warm but there sure isn't much ventilation for it in that little box. Most vfds have a diagram that shows recommended clearance on all sides and this one definitely does not fit those recommendations
 
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rattle_snake

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Like the previous one, the thermal aspect is not ideal. Typically it doesn't run for very long at a time. Drill one hole maybe two.

The VFD is force cooled, so the clearance that passive things need to transfer heat to ambient is not equally applicable. There is no published rating for cheap **** like this.

The foam forces most of the hot air out, and fresh air in. Without it will cavitate and not cool as well. There are vents on the side of the case that will allow internal airflow, and then the fans will pull it some of it out. The PCB with silicon devices on it is directly above the heat sink. Doing a much better job cooling the heatsink with air dam will make the ambient air temp inside the VFD lower.
But this is my opinion. Theta J.
 
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rattle_snake

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@rattle_snake : Looking great, Justin!

But, please, drill some random holes in that DP table. You're making the rest of us look bad.
There are a couple small ones... 20 years
I have a nice Dayton vice I bought because I drilled a hole in it. Was working at a place with a machine shop, and my equipment at the time (college kid) didn't drill large (3/4") holes well. Damaged the vice at work and bough a replacement. The machine shop manager was quite surprised anyone would take accountability for something like that.
 
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rattle_snake

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Yup I used the wrong word.
but I was asking Ego so he could tell the class and take credit.

I wouldn't expect any less from GJ. Surprised no one has said 2 hp is not enough? slacking in here....
 
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rattle_snake

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I should have started with my standard disclaimer:
 
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rattle_snake

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Used the drill press some and left the display in temperature mode. It doesn't go up more than 2 C even if I intentionally leave it running for awhile between drilling. Left on but not turning the temp is static.

Unloaded or typical load current is about 0.4 A, 88 W. Even if VFD efficiency is horrific, waste heat generated is probably less than the light bulb it came with. :fawk:
 
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