revised August 13, 2018
By Kyle Anderson, Co-Founder & Product Visionary
All of our grinders use a powerful DC motor that produces a very high torque (even at "locked rotor" conditions). In every electro-mechanical device, there should be some kind of easily replaceable or automatically resettable "fuse". In the case of the Encore, Virtuoso, and Preciso (discontinued) we have two of these safety systems.
The first is an automatically resettable thermal "fuse" (PTC) that when triggered, cuts power to the motor down to a few milliamps until the timer switch turns off. At this point it can cool down and automatically reset. The PTC requires a "locked rotor" event to last for about 2.5 seconds before the PTC is triggered. Under most abnormal conditions (i.e. a rock or un-roasted coffee bean), the grinder will stall, then the PTC will trigger, and after the obstruction is removed, the grinder is ready to go again.
In certain circumstances, the shock to the grinder may be great enough that the motor doesn't have time to stall, but rather the ring burr carrier can act as a mechanical "fuse" . This is the second safety system. This shows up as inconsistent grind and a broken tab on the burr holder. In the past, our main drive gear was the weak link and this was inconvenient to our users, because this was not a user-replaceable part. We have since redesigned our entire gearbox so it never fails. As a result, 100% of the torque produced by the grinder is resisted by the ring burr carrier. The ring burr carrier can easily be replaced by the end user, so the grinder is back in action quickly. We have over 312,000 units in circulation and we go through about 7,000 burr holders per year. This works out to 2.73% of our Encore, Virtuoso, and Preciso (discontinued) grinder owners replacing ONE burr holder per year (97.2% do not). In almost all cases, failure of this burr holder part is due to foreign objects (stones, screws, etc), un-roasted or light roasted (before 1st crack) coffee beans in the grinder.
Now you know why we have a plastic burr holder and why it's a good thing!
If you need to change your burr holder:
Originally posted November 2013