Thread: Arboga EM825 mill Christmas present

Nice
Can you get a picture of the plate on the motor?
If its a dual voltage motor you can use a "cheaper" inverter.
If its not it might be better cheaper changing the motor if its easy enough.
Stuart

Hi ST,

Will get a snap of the motor plate, did not know it might be dual voltage.

I don't reckon changing the motor would be an option, it's sort of built in as part of the mill head.

There's a picture here of what it looks like.

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Ken

Yeap and inverter is it. Now you just need to know if its the cheap one or the expensive one.
You could get it rewound but that would likely cost more than the inverter.
Stuart

ST,

What do you mean?, is it "the cheap one, or the expensive one".

Ken

Sorry I was talking about the inverter.
If its a dual voltage motor you can get an inverter for roughly $200. If it isnt you'll need an inverter that costs roughly twice that.

Ken, it's a two speed motor, so unfortunately 415v only. You have a couple of choices:

1. Make three phase one of two ways:

a. Build a rotary phase converter from a 1.5 kW motor from information widely available online. Cost approx 1 ebay motor +$150 for capacitors (or less). This will generate 240v three phase from single phase input.

b. Buy a 1.5 kW VFD, single phase input, 240v three phase output. Ebay most likely, used for under $200

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Then change your 240v three phase to the nominal 415v by:

wire in a 240v/415v three phase transformer. Exact output voltage 380-440v should work OK.

You can find these inside a Transarc Tradesman arc welder, preferably an ugly cheap one off ebay for cheap.

Next best is to take it to a trusted rewinder who can convert it to 240v three phase single speed and then use the cheap VFD option (#2) as above, no transformer required. This will give you three phase, and a rheostat for your intermediate speed needs.

Good score

Greg

Ken, there is another thing I didn't mention: Free manuals can be found at:
http://www.hhrobertsmachinery.com/Su...spareparts.pdf

The U-2508 is the later version of the 825, and most of the features are the same. I have a mate who has an 825 manual-I'll see about getting a copy made for you.

Greg

Oops. That's a parts manual only, and in Swedish. You'll need a backpacker/interpreter for that, in which case forget the mill anyway.

Greg

And don't go buying any way oil...I have enough to lubricate this entire forum for life.

The third way:

Attached find a copy of the cutaway drawing of an Indian copy of the Arboga. All the Swedish mill/drills and the Asian copies have the same basic features. The internal motor is unique, and is not a direct swap for anything else. However, you will note that the area above the motor is free. It would be possible to fit an externally mounted face frame motor to the top of the head in the manner that the later machines had. Not as elegant, but it is another way forward.

You wouldn't need a two speed motor since a vfd would do that for you.

This is the least likely solution, but I wanted to throw it out there in case you get stymied with a rewind.

Greg

Hi Greg,

Thanks for all your info. Would appreciate you asking your mate about a manual.

Now, I am confused. I was under the impression that all I would have to buy, was an inverter with a 3 pin plug on the input end, and 4 terminals at the output for 3 phase. Chuck in a pot, and wallah.

What's this about a transformer?

Ken

Unless there are VFD's that can also boost the voltage to 415. Maybe there are, I'll have to check.

Many sub 5 hp three phase motors can be connected in star or delta, 415 or 240v. Two-speed motors cannot be.

Greg, I have seen a conversion similar to the one you describe, it was not pretty but probably functional, from memory the motor was mounted on a framework behind the column and a belt drive connected to the extended shaft out of the gearbox.

Ken, the instructions consist of one and a half pages of text, one page of exploded parts diagram and a wiring diagram. I can send you a copy if you would like to get in contact.
The motor lamination stack is press fitted into the motor housing which is part of the mill's framework, three issues arise; is the winding slot layout suitable for rewinding as a single phase motor (the motor in mine was burnt-out but I had it rewound as three phase, $160 about ten years ago) ; how can the motor be started and, the power available would be reduced compared with the three phase motor. I think the VFD option is probably the best and would increase the value of the machine. Mm.

Originally Posted by gregoryq

Unless there are VFD's that can also boost the voltage to 415. Maybe there are, I'll have to check.

There is........... I have one, but as I said they are about twice the price or even more as I haven't found 1.5hp one yet.

Originally Posted by gregoryq

Many sub 5 hp three phase motors can be connected in star or delta, 415 or 240v. Two-speed motors cannot be.

Some 3 phase motors are dual volatage some arent.
No ideas on two speed motors

Oh dear oh dear.

Looks like I might have bought a lemon. I suppose before I panic, I should really determine what sort of motor is in it first. I don't have the mill in my possession yet, will have to wait until Monday to find out.

Ken