I got a new GPS and so I went to test it out today. I also put a new spare motor I got on the plane, and unfortunately that motor only lasted about 10 seconds before smoke came out of it.

After the motor died, the speed controller died too.

I noticed when I was putting the propeller on the motor that it didn't spin as freely as the other motors I have. Unfortunately I didn't think about how that meant that it was going to consume more power.

I took the motor apart to find out what was keeping it from spinning freely. Both of the bearings spin very freely, and there's nothing else that the spinning part of the motor touches. Yet when the spinning part is put onto the stationary part, it suddenly has resistance to turning.

It eventually occurred to me that this might be because some of the motor wingdings are shorted out. So I picked up the good motor (I have two of these) and connected two of the terminals together and, sure enough, it exhibits the same kind of resistance. So apparently some of the windings are shorted together.

I'm not sure how these are wound, but I'm assuming that just some of the wires being shorted is why the coating melted off of some of the wires and yet others seem fine. I'll have to see if I can get the eBay seller to replace it.

This is the second motor I've bought from that seller, the first one being the same model, and yet this one, despite looking similar, has many differences. The sticker on it has the same text, but written in a different font, and it's cut with rounder corners. The orange metal is a slightly different color and shows evidence of different machining. One of them has a lot of rough edges around some holes, the other is smooth. The wires are a different size, even the magnet wire inside the motor appears to be a different size. Overall it seems like they came from different manufacturers.

It's funny how we can't manufacture anything in the U.S., but in China they can build no less that two factories to produce the exact same product but seemingly with a completely different process. I really wonder why that is.