Found "the upper limit" of a Hobart N-50
In preparation for a for a "Tonka Bean Bread Pudding" to serve 50, I was mixing up a double batch of Peter Reinhart’s Challah in my Ankarsrum but it was just not getting a good mix even after switching over to the dough hook.
It looked like it would _just_ barely fit in the 5 Qt. Bowl of my Hobart N-50, and it did.
2 minutes on first speed went no problem. Gave it a 5 minute rest and started it up again, for the first two minutes everything was fine. At minute 3 I heard something I have never heard out of any Hobart mixer, the motor started to bog down. By minute 4 the mixer was severely straining and giving off the tell-tale "overheating electrical" smell. I quickly shut it down, removed the dough hook and let it run for a few minutes to cool the motor back down.
No harm no foul, but I'll know not to try that ever again.
An old retired professional baker who used to frequent here once told us that he would have never considered making more than 1.5 lb of dough in his N-50.
I've done intensive mix of up to 2 Kilo batches of high hydration (>70%) bread doughs with no problem in the past. But since getting it, my Ankarsrum (really an Electrolux Assistent) is my "go-to" machine for almost everything "bread".
The (2) N-50's are almost exclusively used for (Italian Meringue) Buttercream's and cake batters and that ilk these days. But they still kick the snot out of any KitchenAid, even my old K5A and K5SS.
At 5-10 times the cost why would you expect anything less?
I would expect, or accept nothing less.
"No harm no foul, but I'll know not to try that ever again."
This is not necessarily true. Overheating to the point of that "electrical smell" may have already compromised the winding integrity and could lead to motor failure. I point this out because your statment implies to others that this occurance did no harm and this is not the case. While the motor may well continue to run, its life has been degraded and the motor can only withstand so much of this before it fails.
Some damage could have indeed been done.
"An electric motor's insulation system separates electrical components from each other, preventing short circuits and thus, winding burnout and failure. Insulation's major enemy is heat, so it's important to be sure to keep the motor within temperature limits."
( Ref: Helping Motors Keep Their Cool, Chris Medingger, Leeson Electric Corp. Grafton, WI , http://www.maintenanceresources.com/referencelibrary/electrical/helping.htm )
Motors are best kept cool but they can get hot. Motor armature wire on cheaper motors may be only be rated at 150C but I'll bet the Hobart is 200C wire so you might indeed smell the motor but it doesn't mean you have compromised it.
Rob
Yes, indeed. This is why I said "you may have have already compromised". The reason for my post was not to make SandSquid feel bad, but to warn others not to trivialize overheating. Exactly at what point damage occurs would be very difficult to determine as degredation will proceed both by temperature and duration and until the insulation actually breaks down, the motor will continue to operate. Among other things, as the insulation gets hot, it will soften and the conductors may migrate from their optimal position. HiPot testing and other evaluation may or may not show this, but my point was far simpler. Overheating a motor will eventually cause it to fail and the process is not catastrophic until it is. I simply wanted to avoid giving the message it is OK to overheat a motor.
Overheating is BAD.
When I do get a round-tuit, and update the internal wiring (from the existing cloth wrapped wire), I'll be updating both of my N-50's and installing the circuit breaker (Hobart Part # 00-101491-29-01) to cut down on / prevent future occurrences.
First, I never said it's good or even OK, to overheat a motor.
Secondly, did you measure the field and armature temperature? No, of course not, so you don't know that it overheated. Did the motor smoke? Did you do an electrical test? No, so, again, how do you know it overheated? Do you know that you can get an "electrical smell" from the brushes on an AC/DC motor when a motor is under a heavy load? That's because the of the increased current between the brushes and the commutator.
What you did ONCE was load the motor, you don't know that the windings melted, "migrated" or failed electrical testing.
I advise, after 50 years in electronics, that you watch you mixer and if you notice that when mixing dough the motor struggles when it never used to than it might be a good idea to address the issue but if it doesn't than keep enjoying your mixer and not worrying about what might happen if you don't update the armature.
Happy baking!
Rob
^^^ This ^^^
Wouldn't the "electrical smell" be the odor of the enamel insulation on the wire in the windings getting hot?
You need to listento your mixer's motor at all times. If it sounds like it's laboring, turn it off and lighten the load.
Every machine has its limits.
Arrange to have your mixer fail on July 4th for a lovely fireworks show.
Again, the brushes passing current to the commutator under a very heavy load create high current between the brushes and the armature. Remember it's work and the more work you do the more energy you use. P=EI (Power = voltage times current).
This isn't to say that the motor isn't compromised but you won't know that until you use the machine or have it professionally tested. As I said, watch the motor when doing tasks that the mixer previously ran through without problems or slowing down. If it smells and slows down then the wiring may have overheated to the point that it created shorts between windings.
I've 'cleaned' the coating off the ends of copper wire with soldering equipment in applications and it's pretty hard to get off even using 350C (662F) temps from precision soldering equipment, so I know the 350C is 350C. Probably the older (much older) Hobart motors don't have the level of coating protection as the new ones but Hobart has designed these machines to work pretty hard, even the older ones. Read what they say about the NC50, it's a work horse.
Rob
Or, I could have just given it the proverbial "Italian tuneup"...
Rob, you took me back to Tech School there for a minute;
V=IR, Bad Boys Rope Our Young Girls But Violet Goes Willingly, Roy G. Biv, ahh good times, good times!
Luckily, I still have an _almost_ complete N-50, "parts donor", should I ever need to replace the field, etc.