Orac Inverter

[seaman77]

...I am trying to locate the ends of these two gray wires (white arrows) in the attatched image of the ORAC Inverter. Mine was delivered with these wires disconected and the motor will never start except if i make the conections the way they were done by the manufacturer. If anyone knows where these wires go and what they do, please help!
It seems one comes from the large filtering capacitor(power supply capacitor).
Is my machine missing a transformer or something? In a modified machine like mine I see these wires go to the secondary of a trnsformer but what it does or what voltage is present there I have no idea. Besides this transformer is not present on my machine.

Thank you and kind regards to all !

P.s. My orac is not modified.

[Triac whizz]

I think theres an electronic lump bolted up by the back of spindle under the end cover that connects onto that

[Martin]

We used to fit what looked like a transformer in the end panel. I allways thought it was a choke for the spindle.

[seaman77]

I see.

[bjohnson]

We just finished a retrofit of our Orac to Mach3. However, prior to this, I went through the unit and schematics to see if we could get it running prior to changing to Mach3.

In our machine, those gray wires do go to a transformer/choke that is located inside the left side of the machine in the spindle compartment. The schematics we got from this board also showed this choke and wiring.

We never got the original VFD up and running. I tested it separately from the the rest of the unit by supplying my own 0-10v and apparently it's cooked .

BTW. We have a bunch of spare parts for this unit.... Power supply, drivers, computer boards, vfd, monitor, stereo (who puts a stereo in a CNC ) , etc. When tested, the computer fired up fine, but nothing would turn on. I fully checked the power supply and it definitely works. None of these units have the metal bases as we used them for our own mounting.

Brett

[angel-tech]

The grey wires do go to a choke, and although the inverter is a little slow to respond it works very well with good torque levels at low revs. The choke looks like a transformer with just two wires coming out of the top of it, and is usually located in the left hand end of the machine behind the headstock. There is a small relay that clicks in first before the spindle starts, and if the machine hasn't been used for a long while the motor can be a bit stubborn to start.

[seaman77]

...thanks anyway! There is no choke here like the one described by you guys. It has been removed I dont know when/how.
Hey bjohnson! Do you want to sell any of the parts you saved after retrofiting your machine? At the moment, I am not thinking of upgrading mine because, I am only familiar with the G-code programming. If I switch to advanced cnc programming like Mach-3,
I have no idea if i will be able to program and make parts out of an Orac. I am sure I'll need to read a lot before that and have no idea where to start from yet, even though it sounds challenging to be able running this small machine through windows and with a laptop maybe.

Dimitri.

[angel-tech]

If you can't get the inverter working, you can replace it with an inverter from "drives direct" like this one
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:IT

[seaman77]

Thank you Angel-tech! I am checking this already. Maybe this manufacturer makes a slightly higher capacity unit. As you may know screw cutting in the Orac is not the best chioce due to the low power 1hp motor especially at low revs where larger diameter threads are made.

[angel-tech]

they sell a vector version which has better low end performance.

http://cgi.ebay.co.uk/1HP-3-PHASE-VECTO ... 588a108dc1

[seaman77]

...Thank you Angel-teck! I am sorry, i had no idea. Do you know if this unit has provisions for auxikiary inputs to be used but the machine's controller?

have a nice weekend!

Dimitri.

[angel-tech]

there is a manual available on his site for the inverters, but they have the usual 0-10v (and others) input for speed and a two way switch for direction.

[seaman77]

,,,Ok then! I may go for it. But still I have to fix the faulty inverter. I am thinking of conecting the two grey wires together without employing the choke. Do you find this risky?

[angel-tech]

no idea, but buying a choke wouldn't be difficult.

[davidimurray]

Hi Guys

Seaman - did you get your inverter going? I've been asked to help a friend out with his Orac and having a look through the boxes of bits last night I couldn't find the choke. Did you manage to source another one or has anyone got one going spare?

Cheers

Dave

[seaman77]

well, Dave...I did not get to a point to make it running yet. I am reading about chokes these days and there are so many. RF, AC power, AC/DC, Frequency range also is a factor to be seriously taken into account.In my case I understand, I should not look for one designed to operate above 100Hz. I do not know what to look for yet. One publisher gives details of how to make one. That book is called <coil design manual>.
One of the cables who's other end is missing on my machine is connected to a large electrolytic capacitor.Or it looks like a capacitor. It has no microfarads printed on that thing. It only shows voltage range.You can see that on the photo. My first post on top of this page.

regards

[angel-tech]

i would go a fair bit above 100hz, as the inverter runs the motor at 100hz on full speed.

[seaman77]

...So 100Hz is where the Orac inverter operates at maximum speed. I did not know that. It looks a good idea to follow your advise then Dave. Thanks!

[kato]

Hi,
after my mach3 conversion the spindle became much weaker on my ORAC.
I dont have a cable like this. Can this be why?
Ive ordered a new 1hp inverter and motor, but untill I got this up and running it would be whery nice to fix the old.
Pictures where things are connected would help alot.

/Jim

[angel-tech]

the original inverter supplied with the orac has a lot more slow speed grunt than the basic inverter packages out there, there are better inverters but they increase in price substantially.