Does the "O-Zone" odor mean something bad is happening to the engine motor?

The ozone is created from the sparks of the brushes, but also typically the wheels and pickup rollers contribute.

You might be asking then why doesn't my can motor create as much?

Lots of reasons. The AC universal motor uses electromagnet coils for both the armature and the field, where the can motor uses permanent magnets for the field.

The can motor is getting DC and is lower inductance so less sparking, where the AC motor and it's series inductance produces more kickback and thus sparking all while also being on AC VS DC.

The universal AC motor typically draws higher current- also causing more amperage and spikes at the wheels and pickup rollers also sparking.

One way to think of it is the can motor being DC, along with the smaller commutator and higher precision, being driven with rectified and often filtered DC, along with higher efficiency and thus less current- all equals way less ozone.

The universal AC motor is brute force. The commutator and all that inductance, larger diameter and less precision in the commutator, high inductance and lots of inductive kick- basically you created an spark machine to create ozone.

What Vernon said, but I also note you said you were pulling a heavy consist for an extended period, which would tend to both increase the ozone production and extend it over a perhaps longer than usual period, so it's not surprising that the aroma might have begun to reach a noticeable level. A low level of ozone is not particularly damaging in and of itself, nor IMHO is it an indication of something going bad (scorched or burnt smells are a lot worse!), but better ventilation when you run a similar load for extended periods might help if you find it offensive. Good luck!

With my reading comprehension questionable at best, I don’t see where OP indicated he was using universal AC motors, unless Vernon’s post was for educational purposes only?

@Mark V. Spadaro posted:

With my reading comprehension questionable at best, I don’t see where OP indicated he was using universal AC motors, unless Vernon’s post was for educational purposes only?

As the DC can motors used by pretty much everyone are not high-end brushless type, the can motor referenced in the OP post still have brushes.

@H1000 posted:

As the DC can motors used by pretty much everyone are not high-end brushless type, the can motor referenced in the OP post still have brushes.

How can you discern this from his post?

@Mark V. Spadaro posted:

With my reading comprehension questionable at best, I don’t see where OP indicated he was using universal AC motors, unless Vernon’s post was for educational purposes only?

It's possible I got it wrong and he was not comparing can motors to the typical universal AC motor "Pulmor"

@Mannyrock posted:

I have started running some of my larger dual can motor engines, two engines at a time, pulling fairly heavy trains, for 20 minutes or so.  Unlike most of my experience in running my can motor engines, I am getting fairly strong O-Zone smell after 10 minutes or so.

Let's say they are Williams dual can motor locos then. Typically, those do draw higher current, motors are wired in parallel so combined current is even higher, heavy load, tall gearing. So even though they are can motors- the motor power and current- they too will produce ozone.

Well, to answer some questions, my prior experience was always with the 1960s Post War Lionel engines.   This was back in the mid 1960s, when I was running either Super-O Gauge Lionel engines, or HO gauge Lionel engines.  Lots and Lots of O-Zone smell back then!

Very little smell when I restarted this hobby 3 years ago, using Williams/Bachman and Lionel O Gauge dual can motor engines, made in the 2000 to 2020 era.  I did have a Pullmor that I got at a flea market 3 years ago, but then when I discovered how smooth and strong the can motor engines with flywheels operated, I gave it away.  All are running on conventional controls from the transformer.

Thanks,

Mannyrock

@Mark V. Spadaro posted:

How can you discern this from his post?

Pretty simple, I know of absolutely no current or vintage O-gauge model train locomotive that uses brushless DC motors.  AAMOF, I don't know of any scale that uses them, though maybe there are some floating around.

Back to the title of this so I feel like we have some closure:

"Does the "O-Zone" odor mean something bad is happening to the engine motor?"

I won't define it as "bad" but it does represent wear and tear. Ozone smell, but also components getting hot as part of that total smell are associated with the load (voltage and current). Simply put, lots of power usage with wheels and rollers on rails- due to imperfect contact, results in sparks, which create ozone and heat. The harder you work your train, the more current it draws at a given voltage, even worse with cars like incandescent lighted passenger cars drawing power and pickup rollers and wheel- results in wear and tear.

Specifically, the rollers and wheels spark erode (same principle as EDM Electro Discharge Machining), as well as the brushes and commutator. Heat also plays a role and melting and deforming of components- typically insulators, end bell brush holders, armature winding insulation, pickup roller insulators.

Also, if this is a DC can motor loco- there is somewhere a rectifier or diodes likely also taking voltage and current and making heat.

Thanks for all of this excellent information.

Glad that I never paid more than $225 for a locomotive, and most were in in the $150 range.

So, I guess if end up wearing them out, then it is no big deal.

I was just worried about a sudden motor burn out, or a fire, or something melting, which appears not to be the case.

Thanks  again,

Mannyrock

Robert Duvall in his train room?  "I love the smell of ozone in the morning!"