Small coreless motors

[Chris333]

I recently bought a AZL Z scale Mikado, it comes with their "new" 7.5mm dia coreless motor.

When running the locomotive I hear a lot of what I would call chattering and it isn't exactly smooth. Here is a great quality  video showing what I mean:

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There is no binding in the gears as you can see me pushing it freely. It sounds electrical and the motor shaft has a lot of back-n-forth play in it.

I'm using a MRC tech2 2800 in the video, but it is the same with a Zthek controller.

Any ideas what I should look for next?

[wazzou]

Yikes.  I can't lend any help, but that motor is a disaster.  It'd be interesting to see if anyone else steps forward who has purchased this same engine and what their experience is.

[Chris333]

Apparently despite only been around a loop of track about 5 times since opening the box the wheels were very dirty. I'm getting it to run much better now, but there is still more chattering going forward than reverse. I'm uploading a new video now.


I was told to expect gear noise, but to me gear noise would happen at higher speeds not at the lowest possible speeds.

[peteski]

Try running the model using pure DC power.  Something like a 9V battery (which might be a bit too much for Z), or couple or three 1.5V cells in series.  It is possible that the motor is so sensitive that it picks up he AC ripple on the DC voltage from the throttle.

[Chris333]

Pete,

This is the update video:

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In the video it is running off the MRC pack.

[Philip H]

Interesting second video.  No or little chattering going in reverse, but noticeable chattering going forward.  You say the gears aren't binding but is everything seated properly?  I know - as I am sure do you - that a lot of noise in older N scale locos was from poorly engineered drive trains with loose gears, universals, etc.

[Chris333]

Here is a new video using a Zthek controller that is powered with a 9Volt battery:

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In the first video you can see I removed the worm and I'm able to push it without binding the chassis.

Also gear noise would get louder the faster it goes, but I only hear the chattering at very low speeds. It sounds electrical to me 

At least now it is running smooth.

[Chris333]

I just counted a 12:1 ratio from the motor to the wheels. Think that just answered my question about putting a 4:1 gearhead in it.

[reinhardtjh]

Have you run the motor when it was disconnected from the drive train?  I watched both videos with and without sound and noticed it runs smoother in reverse and is quieter in revers, but also with the sound off it doesn't appear to lurch or jerk making me wonder if you're right about the "chattering" being an electrical sound from the motor.

The other possibility is some sort of frame short that is more pronounced going forward than in reverse.  Maybe running it in a darkened room might reveal some sparking?

[Chris333]

I think it is a torque thing. Coreless motors have a lot of it, but with only 12:1 gear ratio... A Bachmann N scale 2-8-0 has a ratio of around 45:1.

AZL had been using Faulhaber 0816 motors, but for this locomotive they came up with their own 7.5mm dia motor. My first thoughts were that the new motor was crap:


So I popped in a 8mm Maxon from a Micro Trains locomotive:

It ran just a slight hair better, but soon as it hit a curve the extra small amount of friction would have that motor chattering and slowing down the locomotive.

And then... I grabbed the big ammo. A 0816 Faulhaber with a 4:1 gearhead    These things are like a magic wand. The gearhead is almost as big as the motor so I had to make it fit:


I took video of the Maxon and gearhead running, but Youtube would just spoil how sweet this thing now runs. I have been messing with Z for a while and this is my first real locomotive. I don't even care that it took a $75 (Motorman price) motor to be happy with it.

[Chris333]

Here goes:

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