three phase robur

[xristrettox]

I've heard about them, but have no experience with them.

Anybody out there have experience? What's the deal with three phase anyway? Is this covered in another thread (quick search couldn't find it).

We are considering upgrading, and as rumor has it, it will grind your dose in two-ish seconds. Anybody confirm this?

thanks,
billy

[terry]

Billy,

come on up to Oly next week, and you can try one of our out.


Terry Z

[Kyle Glanville]

Billy -

I used them a bunch in Greece. They may be the best espresso grinders manufactured today. That doesn't mean they're good (cuz no espresso grinder is) but I think they are the best we can get our paws on in the states.

And yes, they are really effing fast. I'd say roughly 10g/sec. But the burrs are only spinning at around 450rpm. Very cool....

[nick]

And yes, they are really effing fast. I'd say roughly 10g/sec. But the burrs are only spinning at around 450rpm. Very cool....

Then why the hell isn't there a 110V version with the big burr set? I don't understand why they couldn't have just built a Robur with the big 83-or-whatever-millimeter burrs, at a SLOWER than 450rpm rotational speed (speed vs. control and quality), on a 110V voltage.

There's the LM prototype grinder with the same sort of big burrs... I dunno. So far, it seems that nobody (grinder manufacturers) seem to "get it." I hope La Marzocco can.

[Jimmy Oneschuk]

supposedly, 3-phase motors run cooler than single phase...

Although I have heard elsewhere getting the burrs in motion is where your heat will be created. Andy S will know!

[tim]

Bigger burrs and much faster grind than the single phase, but I don't know if the RPM is slower. The burrs are huge and the grinder doesn't heat up as fast as its little brother. But it will heat up eventually.
All in all a good alternative to the Compak K10

[Andy Schecter]

Then why the hell isn't there a 110V version with the big burr set? I don't understand why they couldn't have just built a Robur with the big 83-or-whatever-millimeter burrs, at a SLOWER than 450rpm rotational speed (speed vs. control and quality), on a 110V voltage.

Because Mazzer thought about how many 83mm/110v Roburs they'd sell in a year, and compared it to how much it would cost to develop the new motor/gearbox mechanicals. Then, like everything else having to do with 3W espresso, they decided to pass on it.

Somehow I convinced myself to order a three phase Robur for home use. :-0 I have no idea where I'm going to put it. But I'll soon be running it on a frequency drive.

[Andy Schecter]

supposedly, 3-phase motors run cooler than single phase...

Although I have heard elsewhere getting the burrs in motion is where your heat will be created. Andy S will know!

Three phase motors are a little more efficient at getting the burrs in motion and keeping them in motion. So they run a little cooler.

But the other source of heat in an espresso grinder is friction caused by the grinding itself. Bigger burrs at slower speeds seem to help.

Unfortunately, the classic espresso grinder design keeps heat trapped inside very efficiently, since the beans sitting in the hopper choke off convection, and the burr carriers are mostly buried inside a massive housing.

[James Hoffmann]

Unfortunately, the classic espresso grinder design keeps heat trapped inside very efficiently, since the beans sitting in the hopper choke off convection, and the burr carriers are mostly buried inside a massive housing.

Having had a grinder apart and sat in front of me for a while now I have to say this is a very frustrating problem that there is no simple mod/solution for. Installing a fan is easy but I am now more concerned about the heat in the burrs and not the motor itself.

[Andy Schecter]

Having had a grinder apart and sat in front of me for a while now I have to say this is a very frustrating problem that there is no simple mod/solution for. Installing a fan is easy but I am now more concerned about the heat in the burrs and not the motor itself.

Efficiency in getting the heat out of the burrs is one of the advantages of an open top, hopperless grinder like the Versalab.

If you set up a doser to drop whole beans into an open top grinder, you leave room for the heat to get out. And the beans are not heated by sitting on the hot burrset.

[Philip Search]

What Andy and others have said is correct, the heat isn't from the motor... the motor just helps keep everything hot. The grounds in the burrs, the beans above, and the coffee in the chute all insulate the heat to the burr set, heat generated by the way the beans are crushed, then distributed to be cut fine. Most every grinder heats to 100-120 degrees within about 30 minutes of constant use, including a standard robur. The data on the 3phase that I have isn't complete yet. I can say though, I have seen a solution put on a standard espresso grinder that kept the grouds at less than 75 degrees no matter the volume.

[xristrettox]

... and that solution is...

[Philip Search]

I can't say! The person who paid for the research has to finish the report befor I can blab.

[trabant]

Those of you using the 220 Robur, how are you supplying the 3 phase power? Variable-frequency drive? What have been your installation costs?

[Brent]

Those of you using the 220 Robur, how are you supplying the 3 phase power? Variable-frequency drive? What have been your installation costs?

There is someone here in NZ providing gear to frequency shift single phase to deliver three phase for motors. They have a US agent. Yeah, if you wanted one, and if it's cheaper, you can buy it in NZ and get it shipped through me. They are not necessarily to far from me.

Found it while looking at generators for sale between power cuts last weekend

[trabant]

This leads to another question: will the 3 phase be allowed in competition, ie, will the necessary power outlets and/or any converters be provided? After all, the USBC is just around the corner...

[Brent]

This leads to another question: will the 3 phase be allowed in competition, ie, will the necessary power outlets and/or any converters be provided? After all, the USBC is just around the corner...

The key there is that the power outlets have the current capacity to deliver...

I have worked a number of venues where we had to put high current slow blow fuses (see example pic) into power boards because they couldn't handle much more than a low watt reading lamp


Generally with a venue they should be able to provide x power. From there you normally have your own distribution system, or the venue arranges it.

Depending on the venue this can be anything from part of the service to hellishly expensive. Specific requirements past the outlet are normally resolved by the person requiring the power. So I would expect if I required 3 phase / 220v / 50 hz that if it wasn't stated as available I would need to work it out myself. I would also not expect to be able to fit a slow blow fuse to accomodate the current...

In the music world most musos who had special requirement gear had the power units to deliver what they wanted to the unit from whatever power was available.

[Ryan Willbur]

I don't see anyone (without some sort of timing device) benefiting from a 3 phase Robur in competition. I mean, really, when you're shooting for as little grind as possible, do you really want coffee flying at you at 10g a second...

Oh, and as I was so awakenly reminded just a bit ago... Billy did take 2nd in the USBC with a super jolly... so why waste time and energy?

[Brent]

Oh, and as I was so awakenly reminded just a bit ago... Billy did take 2nd in the USBC with a super jolly... so why waste time and energy?

what if he had a robur???

[nick]

This leads to another question: will the 3 phase be allowed in competition, ie, will the necessary power outlets and/or any converters be provided? After all, the USBC is just around the corner...

The answer is NO.

Only 110V 15A is provided. If you blow a circuit because you have too much shit on the circuit, it's not the responsibility of the USBC committee to accomodate your requirements.

[Andy Schecter]

This leads to another question: will the 3 phase be allowed in competition, ie, will the necessary power outlets and/or any converters be provided? After all, the USBC is just around the corner...

The answer is NO.

Only 110V 15A is provided. If you blow a circuit because you have too much shit on the circuit, it's not the responsibility of the USBC committee to accomodate your requirements.

I've been running my brand spankin' new 3 phase Robur on a frequency drive. It plugs into a standard 115v circuit and draws about 9 amps. So you'd have to have a lot of other "shit" on the circuit in order to blow it.

I have the drive set to deliver 230v 3 phase at 50 hz (rather than the N. American standard of 60 Hz). This supposedly drives the burrs at 420 rpm (haven't measured the rpm yet). 420 rpm is the speed at which it runs in Europe, and I presume the engineers knew what they were doing when they designed it that way. It's possible that the burrs may run a little cooler running at this lower speed rather than the 500 rpm they'd do on 60 hz.

With this setup the Robur is delivering a little over 4 grams of coffee per second, which means a shot is ground in about 4 secs. If that's not fast enough for your baristas, perhaps they should switch to decaf.

I also have it on a timer, so that one push of a button runs it for 4.2 seconds, 4.5 seconds or whatever. Nice.

This is still in the experimental stage, but so far results are completely trouble-free. Of course, I'm a little concerned about this placard that came packed in the Mazzer box:

[Andy Schecter]

I've been running my brand spankin' new 3 phase Robur on a frequency drive.

Oh yeah, how does it taste?

Still to early to be sure, I've only pulled a dozen shots so far. And I'm comparing it so far to a humble Mazzer Mini that's seen about 75 lbs of coffee through its burrs.

But Schomer's statement that espresso made with conical burrs is heavier and thicker seems right on. He says it delivers more flavor into the cup. I'm not sure about that yet, but I've got a lot of playing to do.

[James Hoffmann]

It won't let me see the picture (Permissions apparently)

What timer are you using?

[Andy Schecter]

We are considering upgrading, and as rumor has it, it will grind your dose in two-ish seconds. Anybody confirm this?

Hi Billy:

I realize you're probably not going to upgrade until you get back from Guatemala, but...you asked the question.

Running at 60 hz (500 rpm burr speed), my 3 phase robur is grinding 5-6 grams per second, depending on fineness. It might be even a little faster for a very coarse grind in a triple basket.

Running at 50 hz (420 rpm burr speed), it grinds 4-5 grams per second.

[phaelon56]

I've been running my brand spankin' new 3 phase Robur on a frequency drive. It plugs into a standard 115v circuit and draws about 9 amps. So you'd have to have a lot of other "shit" on the circuit in order to blow it.

The frequency drive looks like just what I need for my three phase Mahlkoenigs. Does the drive do what a phase converter does but just for less money? I was looking at close to $500 for a phase converter in order to get one that would hanbdle the extra draw at startup.

Is there a "gotcha" on the frequency drives?