HI all,
I have purchased a used Compak A8 coffee grinder(actually two of them) from a roasting house in Melbourne (which will not be named) for my proposed business. After cleaning and tweaking at home, I finally worked out the programming features. The problem is the dosing times. Not so much in how to set but the actual time to grind! Apparently the seller had imported a batch from Compak a few years ago with slower 800rpm than the original spec 1400rpm (or so). Evidently, his intentions were to preserve the coffee grind quality with low rpm grinding. Unfortunately, the re-spec did not compensate with larger blades to maintain a reasonable grind time. A double takes 13seconds to grind . That is just way too slow for any kind of commercial service. My Elektra Nino does the same in just 5seconds. There is always the option to use the predose program but this defeats my intentions to have fresh ground on demand coffee. Is there anyone who knows if this machine can be restored to original specs? Would this require a complete gear box change or just something minor? Any help would be appreciated.

What if you use a frequency converter to convert from 50HZ to 60, or whatever, higher freq? It will increase your motor's RPM.

If you could get one on a loan to try out, it can make it a simpler solution for you?

BTW, that's an external box. Not something internal to the grinder. Therefore you could use one converter for both grinders.

EDIT: Use Google for "frequency converter 50hz to 60hz", to get an idea.

HI thanks, I will look into that idea. sounds alot less intrusive than taking one of those things apart. I will let you know how that goes. Do you the know how much it would effect the revolutions of the motor?

Theoretically it will now be 960 rpm.

Well, you mean the revolutions of the burrs. We don't know the revolutions of the motor because there is a gear.

The formula is RPM= HZ * 120 / number of poles. And then there is a reduction gear, and then there is a sliding (slip) factor that is dependent on the torque... So we don't know the RPM of the motor, only that theoretically the burrs will turn 20% faster. Sorry about the blah blah blah... LOL

BTW, I checked and the original RPM of the A8 is 1300rpm, not 1400.

Thanks Le Dan,
That was quite a comprehensive explanation (lol) but necessary since I did ask. Anyway, not sure where to get one of these converters here in Australia. I googled and found links to specialised industry equipment for large machinery application, but not domestic use. Then there was this funny Japanese scientist with a vid on youtube which was priceless but sadly again, I don't have my trusty 2000 in 1 electronics kit so could not build one...(and since I don't have a clue). Do you know perhaps a brand of such devices that could be searched to narrow the google result? I really appreciate your reply by the way.. just wish to point out I have no electronics ability other than on/off switches.

Edgar, maybe going another route will be easier for you. I can't do Google searches in Australia. It gives me the US results. :dunno:

I think it will be easier for you to replace the motor back to the original A8 or K8 motor, which is a 1350 or 1300 RPM motor.

What I would do if I were in your situation is to contact Compak and see if they have a record of what they did to modify the speed of these two grinders. Maybe the guy who sold you can give you a hand in that, maybe he knows what they've done?

There are few ways that they could have done it. (Slowing the RPM). They could have put a different, slower motor in it. They could have modified some connectors on an original A8/K8 grinder, or they could have changed the reduction gear.

I think changing the reduction gear would probably be the most complicated one, unless they had some gears laying around in their parts box. - I doubt it.

So the two other more viable options are either they changed the whole motor to a slower one, or, they changed some electric connections to slow down the motor.

To find out, the best is to contact them and see what they say. They might ask you to take one motor out and see the plate on it and tell them what it says. Or maybe you take a picture of the motor plate and the wire connections and send them. Seeing that, they will immediately be able to tell you if that is an A8 motor. It it is not, than replacing a motor should be easy, and maybe even not that expensive. Motors like these are maybe ~$200. But I don't know what kind of markup Compak would put on it.

Who gives service to Compak in AU? Maybe contact them.

But I will start with the shop who sold you the units and get all the info you can get from the person who ordered and asked to modify these grinders.

ed63 wrote:Thanks LaDan,
.... Anyway, not sure where to get one of these converters here in Australia. I googled and found links to specialised industry equipment for large machinery application, but not domestic use. .... Do you know perhaps a brand of such devices that could be searched to narrow the google result? I really appreciate your reply by the way.. just wish to point out I have no electronics ability other than on/off switches.

Hi Edgar, I just figured out how to get on Google Australia.... (A friend showed me how China is censoring Google search words results and I noticed the .hk at the end, and figured I'd put .au ... LOL.. It worked!)

Anyway, I found this. It looks really good, but of course I don't personally know this unit. Worse comes to worse, you could put it back on eBay and sell it. But, it looks good. It has a ISO 9001 so it's a good thing.

Take a closer look at this.

"'VARIABLE FREQUENCY DRIVE INVERTER VFD 2HP 1.5KW 7A 220-250V"

You can Google or eBay search the phrase in the quotation above.

Here's one example: http://www.ebay.com.au/itm/2HP-1-5KW-PR ... 287wt_1146


One seller in Hong Kong (Amonstar) says you can email or call them. Phone: (86)13060879940
Email: sales.amonstar@gmail.com