How much does it take to damage a grinder's motor?

Grinders are one of the keys to exceptional espresso. Discuss them here.
cactus_farmer

#1: Post by cactus_farmer »

When removing the declumper of the DF64 grinder, I initially forgot to install washers of a similar thickness to the declumper, which lead to the screws holding the chute to the body of the grinder jutting out a few mm and thus blocking the burr from rotating. I turned on the motor for a few seconds (no more than 5) and the burr did not spin (because it was blocked by the screws). Didn't notice any smoke or burning smells.

I since realized the screws were blocking the burr from rotating and added a washer so the burr could rotate freely again. I then grinded beans to espresso level fineness and the motor seemed OK.

Would this 3-5 seconds of the motor attempting to overcome the insurmountable resistance have damaged the motor permanently?

erik82

#2: Post by erik82 »

If they use a decent motor this shouldn't be a problem nor haver damaged the motor. Especially if you didn't see smoke or smell anything funky.

Oskuk

#3: Post by Oskuk »

But answer to headline: If we talk a baratza, grinding coffee is enough for that! ;-)

malling

#4: Post by malling »

Depends on how much you spend on a grinder, if we talk Baratza it's easy just toss very light roast in it and eventually you burn it out :lol:

If we talk motors found in Mazzer, Mahlkonig then It's almost impossible you really need to deliberately put it beyond max or else it's just not gonna happen, or dissemble it wrongly and even then you stand little chance burning it out. Most of these have protection install so it disengage long before you get to that point.

ira
Team HB

#5: Post by ira »

There are a few ways to kill a motor, none of which you got remotely close to, I can think of three:

Stall them till they start smoking.
Wear out the bearings enough the motor attacks itself.
Let the brushes wear out so far the commutator self destructs.

None of those are likely to happen to a home coffee grinder. You can also wear out the gear box on motors with gear motors but that's not really a motor problem and in the world of grinders is probably caused by plastic gears or grease getting old and brittle more than anything else.

malling

#6: Post by malling replying to ira »

Most grinders above a certain price point has thermal overcurrent circuit-breaker there is little chance you stall them long.

ira
Team HB

#7: Post by ira »

Yes, you can protect against most overheating and a slip clutch can help protect a gearbox, but those are ways to kill a motor.

ltanzil

#8: Post by ltanzil »

cactus_farmer wrote:When removing the declumper of the DF64 grinder, I initially forgot to install washers of a similar thickness to the declumper, which lead to the screws holding the chute to the body of the grinder jutting out a few mm and thus blocking the burr from rotating. I turned on the motor for a few seconds (no more than 5) and the burr did not spin (because it was blocked by the screws). Didn't notice any smoke or burning smells.

I since realized the screws were blocking the burr from rotating and added a washer so the burr could rotate freely again. I then grinded beans to espresso level fineness and the motor seemed OK.

Would this 3-5 seconds of the motor attempting to overcome the insurmountable resistance have damaged the motor permanently?


no this would not damage anything.

the df64 is running on 4 pole asynchronous squirrel cage motor. this is a robust motor that can take abuse. as long as the coil insulations does not get burn. everything is ok, no electronic or brush needed for this motor ( the electronic board inside the motor is just dumb 45 second timer)
i run my DF64 using VFD. at Low rpm i regularly run this 250 watt motor at 1000 watt for a minute. no problem

during my research and tweaking the df64 with vfd i stall the grinder on several occasions. again no problem. everything is still perfect,

the 10uf caps at starting coil limit the current at the start coil. the run coil has enough impedance and thermal mass to handle short stall.

so You Are Fine... :D