Thread Number: 42330  /  Tag: Small Appliances
Mixer Motor Smell
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Post# 445386   8/30/2021 at 21:27 (402 days old) by huskyvacs (Indiana)        

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Have several vintage mixers that work and function fine on all speeds and adjust speed as they should, but they have either a strong electrical fire odor and/or make intermittent small popping and clicking noises.

I know they have likely been run into the ground and used heavily by past owners, but just wanted to get an idea of what to begin looking at first as to tackling what is causing the odor. Grease? Brushes? Soot buildup on the armature?

Also what grease should be used? Food-safe grease?

Coincidentally they are all MixMasters of various ages and one is a Kenmore. I believe they are mid or late 60s and one is a 70s model. The Kenmore might be 40s or 50s.

Post# 445389 , Reply# 1   8/30/2021 at 22:00 (402 days old) by Bob_Smith (North Carolina)        

The "electrical fire" odor you smell is most likely ozone, generated by the natural arcing of the brushes as they slide across the commutator. Said arcing can become noticeably worse over time, primarily due to age-related degradation of the capacitor(s) designed to reduce it, but also general brush wear and fouling. As for the noises, they could also be caused by said brush issues, or just general grime causing internal parts to stick, its hard to say for certain. A good internal cleaning is always a great place to start.


Thankfully, capacitor replacements tend to be pretty straightforwards, swap with the same value, though in the case of Mixmasters you'll probably have to jury rig your replacement into the old capacitor's body, so it'll mount on the proprietary internal assembly. Digikey is the source I personally use, they have a wide selection and good quality control so you don't get burned by fake knockoffs.


Food safe grease isn't a *bad* idea, but its not 100% required. They have contained "standard" non-safe grease, for decades of hard use, and most leakage you see has occurred extremely slowly past felt or cork seals, rather than from service. It depends on how confident you feel about it, I suppose.

Post# 445400 , Reply# 2   8/31/2021 at 08:18 (402 days old) by suckolux (Yuba City, CA)        

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Their mechanical speed control also uses resistance, that gets hot and burns off flour, ect.

Post# 445406 , Reply# 3   8/31/2021 at 12:20 (402 days old) by texaskirbyguy (Plano, TX)        

Open them up and see if the motor moved freely. Most of these units older than 30 years will have solidifying grease in the gearbox and bearings, which will put a good load on the motor. The last Mixmaster I worked on was like this. Most of its power was consumed overcoming the grease resistance and it would bog with simple cake batter. The motor ran hot as a result and smelled bad.

If grease is solidifying, it should be cleaned out and replaced.
If the gearbox design could allow separated grease oil to get into the food (like in many Kitchenaides) then use food-safe grease. Otherwise, regular grease will work fine. Check the gearbox to see how it is designed. Raised turrets for the beater connections should allow no leakage. A flat bottom with just seals (or nothing) could leak.

Most of these old mixers use a governor type speed control, which is essentially a switch connected to centrifugal-thrown weights (like a lawnmower engine). This will also cause normal sparking that could be smelled. The switch contacts can get hot and burn flour as mentioned. This is why on slower speeds, they sound unsteady, like a gas engine misfiring.
The capacitor sometimes found across the mechanical speed switch is for EMI suppression to reduce electrical noise (common in AM radios). When the cap shorts, the unit will only run on high speed.

There are other speed designs, like rheostats, that I have not encountered yet. Those are the resistive ones that get very hot by design.

So far I have only worked with Kitchenaid, Sunbeam, and GE mixers - a niche hobby of mine.

Post# 445435 , Reply# 4   8/31/2021 at 21:11 (401 days old) by MadMan (Chicago, IL, USA)        

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Standard fare. Lubricate, brighten up the commutator, make sure brushes are clean, move freely, and have some meat left.

The thing about mixers is that they tend to be overworked like every time they are in use. It's hard work mixing batter, and notice that most mixer paddles/whisks/whatever spin pretty fast, meaning the machine can't have much of a gear reduction. They need a lot of torque, and that torque gets used.

As for food-safe grease... it's neat, and I might even do it if I was working on a mixer I wanted to use all the time. But let's be honest, nobody's gonna get even a tummy ache from the imperceptibly fine mist of grease that *might* end up in the batter.

Post# 445562 , Reply# 5   9/3/2021 at 11:13 (399 days old) by gottahaveahoove (Pittston, Pennsylvania, 18640)        
I was told to

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'run my Kitchenaid" mixers monthly. That will keep the grease circulating. I forget to do that Several times a year, however, I use them quite a lot.

Post# 446503 , Reply# 6   9/26/2021 at 05:56 (376 days old) by kirbyklekter (Concord,Ca.)        
Oh good grease!

I've been cleaning and re-packing all my old Sunbeams and H.Beach mixers. I use the same grease as the fellow on You Tube who does many restos. Lucas Red"N"Tacky grease.It isn't rated as food safe. Comes in a 14oz. grease tube type cylinder with both ends that can be opened to access the grease. Home Depot carries it where they sell drills etc. in the little auto section. I believe it was around 11.00.

If the mixer was used for juicing oranges etc. that appliance stack where the juicer bowl mounts, is a direct portal to the gear box and all sorts of goodies can spill into the grease. So after 60 yrs that grease is tired and really thick if flour got in there too, or whatever.

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