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01-11-2021, 07:31 AM #1
Ab Arboga Drill Press power options
Hi all,
I recently picked up a very good condition Ab Arboga Makiner E825L for free.
The motor plate indicates it is 480V three phase only. I put this in my garage and I’m trying to figure out the most cost effective/safe way to go from 1 phase 240vac to three phase 480vac.
Not having a ton of experience with VFD’s, I thought I’d be able to get a small 3-5Kva transformer to go up to 480vac but I can’t seem to find a VFD that takes 480vac. Most of the ones I come across are three phase input/output.
Considered rotary converter among other things and it started getting a bit expensive.
Any input would be a big help!
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01-13-2021, 09:47 AM #2
I thought I found some information here awhile ago about this press, but can’t see to dig it up again. Trying to understand a 6 wire 2 speed motor has my head spinning a bit.
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01-14-2021, 12:30 AM #3
Single phase 480V input is pretty rare on a VFD because single phase 480V is pretty rare.
You can get a 480V drive that's about twice the size of your motor and that will be fine.
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01-16-2021, 02:36 AM #4
-I have an 825, albeit a 240V/3ph, and here's what I did.
The unit had fallen over and among other things, had smashed the original thin-wall cast-iron control box on the front. That box had a 3-position rotary switch; low, off and high. The switch itself was mildly damaged, but thankfully only in the mountings.
The drill also had a sort of main power switch on the side, between the motor and the column.
I don't have native 3-phase, so my plan was always to run it on a VFD. The 2-speed more was a bit of a complication, but simple enough to take care of.
I removed the 'main power' switch from the side, and fabbed up a new cover plate. Into that plate, I mounted, with some custom fittings, the original 3-way switch.
That takes the feed directly from the VFD, and connects it to the motor. To use it, you make sure the spindle is stopped- that is, the VFD is not feeding power to the motor. Then switch from low to high or vice-versa. Then restart the spindle.
Basically just remember to never switch ranges while the spindle motor is powered, and you're golden.
I then simply fabbed up a new set of low-voltage control buttons to run the VFD, and mounted them where the old switch box was.
The only thing you'd need to do different, is pick up a 240-to-480 step-up transformer, and just wire that in between the VFD and the drill.
Doc.
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01-16-2021, 03:47 AM #5
An RPC will cost about the same as a 480 VAC input VFD. Less if you find a decent motor where the freight won't break the bank
But you will still need a transformer.
Either single-phase on the input of a 480 VAC-capable idler OR the VFD.
Else a 3-phase on the output of an RPC with 240 VAC idler.
Same-again, even if you used a Phase-Perfect. This drillpress isn't one where you can casually swap the motor for single-phase or DC, either. Not impossible. Just not all that easy.
Most VFD mavins say just connect to the high-speed windings of a two-speed motor and let the VFD dial-in lower speeds. I think Doc's way gives you better low-RPM performance. Large holes like lower RPM.
If I were doing that, I'd use a separate ON/OFF switch - the enable/RUN one on the VFD itself only "maybe"
I'd put the Hi-LO function under a flip-cover as a reminder.. maybe even with a switch that cut-off power as soon as I lifted the flap to change the speed.
I once knew a man who seemed never to forget anything.
Damned if I can remember his name.
Same again with switches. If it CAN go wrong?
Later, if not sooner.. it will.
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