Nemisis Blue 10XL

[ddayka]

Hi

I bought this motor on this forum not long ago, used. What is happenning is at start up occationally I get what seems to be a higher pitch squeal, and the shaft does not turn. Has anyone experienced this, if so advise would be greatly appreciated. I am fairly new to all this, so I am even leary of taking motor apart. Advise on how to disassemble motor would also be appreciated . I bench tested motor on 2 cell seemed ok. when i bench tested on 6 cell did it but only occatioally.

Thanks
Dave,

[Jeff Wohlt]

Bearings or something like that.

Do not run it until to you take apart and see what it is. Bushings on the shafts could be shot as well. Make sure the windings and rotor are not rubbing....you will see it if it is.

Tap on the shaft until the back plate pops off. Then remove rotor...mags are very strong so be careful and keep it somewhere it won't attract metal dust or shavings. Bearings are very tight to get back in and have to be driven in nice and straight with a small wood block or something that won't damage the bearings.

Clean the rotor up and spray out the windings with electronic safe spray and feel for anything protruding in them.

I like my ESCs to much to chance it...motors are cheap...might want to trash it if you do not feel good about it.

[sailr]

Are you sure the coupler is tight!!?

[ddayka]

coupler is definately tight. Is there suposed to be any play in the shaft, or is it supposed to be completely tight?

Thanks
Dave,

[ddayka]

Now when I pull out rotor do I grip shaft or rotor, does shaft and rotor come out togeather or seperate. Then how do I replace front bearing does front plate also come off. There are crimp marks on can, but there were crimp marks on back of can as well, and back plate pulled off. How do I know if bushings are shot. Is there supposed to be any push & pull play in shaft or should it be tight when put togeather. Finally if I need replacement bearings or bushings who carries that stuff. It looks like OSE carries bearings but I am not sure about bushings.

Thanks
Dave,

[ddayka]

OK
Got motor apart. How do I know if bearings or bushings are bad?

Thanks
Dave,

[m4a1usr]

There are no bushings on a Neme 10xl unless you mean the end gap washers to eliminate rotor end play. The motor only has 2 bearings. One on the front plate and the other on the end plate. Since you tapped the rotor on a hard surface and drove out the end plate you now will need to buy bearings regardless if they were good or bad before. That is if you want to use the motor. By impacting the rear bearing with the rotor you have applied excessive force and now the one end plate bearing is no good.

Easiest way to find out if a bearing is good is to spin it and feel how smooth it spins. If its new it will only spin a few rotations due to the viscosity of the grease. But it will feel even and not display any wobble. If its used it will spin more freely but again it will not wobble or feel gritty. If you can spin a bearing and it feels clunky or like theres some rough spots its toast.

What bothers me about your original post is the fact you heard a squeal or some sound but saw no shaft rotation. That sounds like a rotor magnet seperation off the rotor shaft. I have seen several BL motors have this occur. To find out if the rotor magnet has become detached from the rotor shaft hold the magnet firm in hand and use a set of vise grips or pliers and see if you can get the shaft to spin while the magnet stays.

I have been rebuilding BL motors for the last 5 years and theres no big secret to them. Finding an issue with one is just looking in the right place.


John

[ddayka]

Thanks John

I did as you said with pliers I can not turn rotor. I wonder if I should just be looking for an other motor. I have a Turnigy 180 amp ESC, would I be able to use say a Neu 1521 1.5D.

Thanks
Dave,

[ddayka]

Is there supposed to be any rotor end play? before I took motor apart the shaft moved in and out between 1\16" & 1/8".

Dave,

[m4a1usr]

Is there supposed to be any rotor end play? before I took motor apart the shaft moved in and out between 1\16" & 1/8".

Dave,

That amount is excessive. Normal end play for a brushless motor should be somewhere in the .005 to .010 range. The less the better. Some amount is required. You dont want any pressure on the bearings from compression so a floating rotor is best in operation for minimal friction.

If your magnet/rotor assembly looks good then you might want to rebuild the motor with new bearings. Bearings are relatively cheap. Before you rebuild the motor though you might want to test the rotor magnets.

The easiest way to test them is see how strong the magnetic force is. Since they are made from Neodymium they will want to influence any material they come close to. And I dont mean materials containing iron. Actualy it is better to test them using material like aluminum or brass.

To see how strong the felt magnetic force is on non magnetic materials you need to pass the rotor very close to the material selected and move it with some minor amount of speed. I.E. pass it over the aluminum almost touching and fast. You will then be able to feel the attractive force. If you swipe it slowly the force will be hardly perceptable.

Any magnet will want to stick to material containing iron. Neo's will want to stick hard. But its testing them against non iron containing material where you can better judge their magnetic strength capability. Its an old trick I learned from some Varian engineers back in the 80's.


John

[ddayka]

Thank John

I tested magnets with both brass & aluminum. Both have attraction, very good test. I am planning to use a thrust bearing this time. Will this eliminate concern for too much end play. Also could problem be with ESC. I wish I had another boat so I could test gear. You think my wife would buy this as a good reason to get another boat? It is for testing purposes after all.

Thanks a bunch
Dave,