Mechanical noise DC brush motor

[muffinman]

Hello,

I'm a bit playing around with a brush DC motor and I want to reduce the nosie it's making.

The thing is quite old and dirty. Would it be a solution to clean it up and lubricate it with something?

Thanks in advance, Maarten

for image, check http://temp.muffins.diskstation.me:8080/dcmotor.jpg

 

[Minder]

Check the obvious, bearings and brushes.
What are you running it on (power?), it appears to be a very basic model.
M.

 

[kellys_eye]

There's inevitable noise from the commutator that you can't do a lot about though.

 

[muffinman]

Hello Minder,

Thanks for your reply.

As far as I'm aware there are no bearings. The centre piece just rotates within the magnet. The brushes are certainly not as new but seem a bit challenging to replace as they don't seem to come of without breaking the thing they're mounted on. So that would be plan B.

It's running on 24VDC, don't know the current it's using.

Since there are no bearing and it rotates within the magnet, I figured that lubricating it a bit could do the trick (obviously taking the right lubricant for job).

Kind regards, Maarten

 

[muffinman]

Hello Kellys_eye,

Thanks for your reply. I know some noise is inevitable, but considering the thing is quite old and rotates without bearings, I figure there must be some room for improvement.

Kind regards, Maarten

 

[Minder]

I am trying to visualize the armature floating between the poles, there has to be some way to contain the armature?
Although the armature end appears to be tensioned against a 'Pip' and an indent in the end of the shaft?
It appears to be a very simple (crude) two pole motor.
Probabally used for a fan application. The armature coils look a little black!
A multi-pole motor will be much quieter.
M.

 

[debe]

It looks like a very old wind screen wiper motor. Ive marked where the bearing is. Also the armature windings look like they have been over heated. If one set of windings are open circuit, The motor will run noisy & the brushes will arc as they pass over the comutator bars that have open circ windings.

 

[duke37]

Possibly a series wound AC/DC motor.

There must be a bearing at each end of the motor shaft ot the rotor will be attracted to one side or the other. It looks as if the the shaft has moved so that there is very little bearing surface at the top. A big hammer might solve this.

 

[Minder]

Possibly a series wound AC/DC motor.

There must be a bearing at each end of the motor shaft ot the rotor will be attracted to one side or the other. It looks as if the the shaft has moved so that there is very little bearing surface at the top. A big hammer might solve this.

If you look at the com end there is insufficient room for a bearing but there is a recess in the end of the shaft and at the top there appears to be a clip with a pip jutting out to engage it.
At least that is my guess!
M..

 

[Bluejets]

Agree with Debe.....armature looks like toast.
Probably been poling for who knows how long.

Waste of time and effort trying to do anything with it. Just get a new/ replacement unit.

 

[debe]

duke37. theres a lot of motors out there that have the bearings on the output shaft end only. With a single ball bearing used as a thrust washer in the end dimple.

 

[duke37]

duke37. theres a lot of motors out there that have the bearings on the output shaft end only. With a single ball bearing used as a thrust washer in the end dimple.

So what were these motors used for? I have looked at hundreds of motors from very small to 250kW and never seen one. Any sideways force on the output would be likely to displace the rear dimple.

Motors on organ blowers are often fitted with plain bearings to keep the noise down.

 

[muffinman]

Thanks for all your replies!

Below I've included another picture of the motor

@debe it's not an old windscreen wiper motor, but you're not far off. It's from a rotating light from (I think) an old firetruck. I guess that also makes it hard to replace if it is indeed toast

The windings indeed do look like they've been overheated. However, if it would have been damaged, wouldn't it stop working altogether?

 

[debe]

In that particular type the drive shaft had a long bronze bush at the gearbox end & the shaft was short with a gear on it . When its running with the cover off, is there exessive arcing on the comutator & brushes?

 

[Minder]

The armature sure looks like it has been overheated!, If the enamel has flaked off anywhere, then a short is possible.
There is a multitude of 24V DC motors now that use P.M. field, rather than the older style wound field.
M.