Drag on Universal Motor.

[John Hasler]

That's true.

I started a thread on...well....another forum. *couch*
They told me it needs a load to run safely, as does Wikipedia.

The grinding wheel is a 2" diamater wheel with a max RPM of 6k rpm I believe.

The nameplate just says Hamilton Beach, model number, and voltage.

Sorry I do not have it with me, visiting somebody in home right now but ill get the info to you ASAP.

Small series motors (such as those in Dremels) can safely run no-load because internal windage loads them adequately (though they may run too fast for your stone). Large ones such as 10HP traction motors will speed up until they explode if run unloaded.

NB: A large shunt-wound DC motor can also be dangerous if you interrupt the field while it is running no load.

 

[David S]

I think wikipedia may be referring to theoretical series motors. Practical motors have armature windage losses as stated, bearing loses and usually an internal fan. Now opening the field on an unloaded shunt wound motor isn't a good thing.

David