New motors - one is harder to spin than the others

[robvree]

Tonight I mounted my new Avroto 2814s motors and I noticed that one of the motors (all brand new) is much more difficult to spin than the others. On all but one of the motors I can give them a quick spin with my fingers and they rotate 2-3 full spins before stopping. On the other motor, with the same finger flick it will only rotate about 1/4 of a single rotation. It is very noticeable the amount of extra resistance.

Should I be concerned? Maybe I should just get the motor replaced now before I modify the wires and find something is seriously wrong when I send power to it.

 

[Droider]

seems odd that. Make sure it is not binding on the mount some how.. take it off and see what its like then.. If its the same I think I would be sending it back.

Dave

 

[robvree]

seems odd that. Make sure it is not binding on the mount some how.. take it off and see what its like then.. If its the same I think I would be sending it back.

Dave

Thanks Dave. That was the first thing I did. I removed the motor from the mount entirely and I get the same result. It doesn't feel like anything is rubbing or grinding, it's just stiff when rotating.

I sent an email to the shop I got the motors from requesting an exchange. No reason to take such a risk with so much time and money at stake.

 

[dolby]

What ESC's are you using? Is the break enabled on that one maybe? Maytech ESC's will break when power is disconnected until the CAP on the ESC is discharged.

 

[robvree]

What ESC's are you using? Is the break enabled on that one maybe? Maytech ESC's will break when power is disconnected until the CAP on the ESC is discharged.

The motor has not been hooked up to any ESC's yet, I just took it out of the box and I'm in the process of test fitting everything on my new build. I haven't even soldered on any connectors to the motors yet.

For the record, they will be getting hooked up to Maytech 30A ESC's.

 

[kloner]

I've gotten this from arf motors but nothing as nice as what your talking should come that way. it either has too much preload set on the barrel/shaft or the bearing has a problem

 

[DucktileMedia]

I've been through everything you mentioned. yes, although i just learned that the Maytechs apply brake when powered off, I know this is not what the issue is. I received one motor that had a lot of mechanical friction as well. It bothered me so much I had Jim ship a replacement. But oddly as soon as the new one came in, the suspect motor started freeing up. It seems occasionally metal filings can stick to the magnets or hold debris. After playing with it a bit and blowing it out with an air compressor, everything was fine. They now all turn exactly the same. Which I was SO happy to find after having Xaircraft motors that had variation everywhere possible, bell housing clearance, E-clips bent, varying resistances, wires from the windings touching the housing. The Avrotos were/are quite nice. Supposedly the exact same thing as T-motors for the record.

 

[robvree]

Solved

Problem solved with the help of Jim from Monto RC. The motor wires still had heat shrink covering the ends of the wires and that was holding the tips together. This caused the resistance in the motor. Once I removed the heat shrink the motor loosened right up.

You learn something new everyday.