Lower grinder's RPM: how to?

#1: Post by **wearashirt** » May 19th, 2016, 11:18 pm

Hi everyone,

Grinder: HeyCafe HC-600. Looks like a Mazzer.

I often have to adjust my grinder since I'm in an outdoor setting. Of coourse, as is the protocol, I have to grind as I turn that collar. I wonder now if there's a way to hack the grinder so as to have an option for a lower RPM, especially when I'm only adjusting the collar.

Is it to upgrade the on/off/auto switch with one that controls the supplied current?

#2: Post by **jedovaty** » May 20th, 2016, 1:01 am

If the motor is a straight forward AC motor (which it looks like?), then you should be able to use a variac (i.e. autotransformer), or even a router speed control (like this: http://www.harborfreight.com/router-spe ... 43060.html). If it's DC, it's a bit more complex. The variac is definitely the better option.

#3: Post by **Katoci** » May 22nd, 2016, 3:30 am

That's not going to work with the coffee grinders. At least not with the big ones. See the similar thread (Mazzer rpm adjustment -or something similar).

#4: Post by **Bluecold** » May 22nd, 2016, 5:37 am

Back when I used my grinder as a doserless I didn't adhere to protocol and it never jammer or anything. Small setting changes are so minute that I highly doubt any ill effects would result.

#5: Post by **bettysnephew** » May 22nd, 2016, 9:39 am

I am making the assumption you may be making changes with beans in the hopper so this may not apply. I single dose and when a change is made I spin the grinder up and make the adjustment while the burrs are still spinning but not powered. Never seems to have been an issue for my grinder. However what you actually need is a variable frequency drive to change the speed as AC motors speed is determined by the number poles in the windings and the frequency applied. The variac will only reduce the voltage applied which allows the motor to "slip" regarding frequency and will greatly reduce available torque. A VFD will also reduce torque when the speed (frequency) is reduced but not to such a great extent as reduced voltage. This can also be partially compensated on a VFD by increasing boost at the lower speed settings. Another issue is that a too reduced frequency setting will not allow the start windings and capacitor to actually get the motor running initially. There is a fairly succinct thread on this site regarding using VFD's on capacitor start motors.

May 30th, 2016, 2:14 am

I suppose, with everything that's been said....that I can't just plug the grinder through a dimmer switch?

#7: Post by **Marcelnl** » May 30th, 2016, 8:07 am

Not really no....a frequency convertor is your best option.

#8: Post by **spencer hill** » May 30th, 2016, 3:38 pm

wearashirt wrote:Hi everyone,

Grinder: HeyCafe HC-600. Looks like a Mazzer.

I often have to adjust my grinder since I'm in an outdoor setting. Of coourse, as is the protocol, I have to grind as I turn that collar. I wonder now if there's a way to hack the grinder so as to have an option for a lower RPM, especially when I'm only adjusting the collar.

Is it to upgrade the on/off/auto switch with one that controls the supplied current?

Hi,
On my own Mazzer Major I solved the speed control. I needed a single-phase frequency convertor.
Follow this link to read about it: Mazzer Major with variable grinding speed