My xl motors make a lot of noise, what causes it and how can I reduce it?

not sure. i haven't taken one apart.

Are xl's known to make noise?

Friction makes noise...

 

Mine does the same, maybe it's just something you should leave alone.

Without a video or sound file, there is no way for us to tell you if your noise is unusual.  XL's are pretty loud in general.

1 hour ago, itoero said:

My xl motors make a lot of noise, what causes it and how can I reduce it?

Some lube reduce the sound. You have to open the housing and grease the gears. Note, you will have a litle power loss since the gears have more friction

Edited April 24, 20177 yr by ben20

12 minutes ago, ben20 said:

Some lube reduce the sound. You have to open the housing and grease the gears. Note, you will have a litle power loss since the gears have more friction

thanks for that reply, I'll leave it alone...

41 minutes ago, ben20 said:

Note, you will have a litle power loss since the gears have more friction

Are you sure?  Sound = energy.  More sound = more power diverted to losses, not output at axle.  Genuine question, as I don't know the answer.    

Edited April 24, 20177 yr by andythenorth

54 minutes ago, andythenorth said:

Are you sure?  Sound = energy.  More sound = more power diverted to losses, not output at axle.  Genuine question, as I don't know the answer.    

I think you can compare it with a driving car.

If it's dry, then there will bea lot of  noise because of friction between the tires and the asfalt.

If it's snowy then there can be a layer of snow (can work like a layer of grease) between the asfalt and the tires which reduces friction and noise and reduces the power the tires have on the asfalt.

By reducing friction I think you reduce noise and power but you lengthen the battery life.

1 hour ago, andythenorth said:

Are you sure?  Sound = energy.  More sound = more power diverted to losses, not output at axle.  Genuine question, as I don't know the answer.    

While that's true, the amount of energy carried by sound is very very tiny compared with the energy output of the motor.  E.g. Philo's page gives the mechanical power of an XL motor at optimal load as 2.21 W, whereas according to Wikipedia, the typical sound power produced by a "large diesel vehicle" is 0.001 W.  If your XL motor is as loud as a real-life truck, then perhaps you do have an issue, but even then the sound still accounts for than 1/1000 of the total power!

I have found that one effective way of reducing noise is to isolate the motor mechanically so that there is less transmission of vibration to surrounding parts and to the table (if the model is on a table).  Rubber parts can be useful for this.

Edited April 24, 20177 yr by aeh5040

Opening up an XL motor is a bit difficult, If you do want to try it, have a look at this topic I made a while back:  LEGO Power Functions Electromagnet

In this topic I gave a detailed description with photo's on how to open a PF XL motor housing.

And if it turns out  something is wrong and it's broken you can always make it into an electromagnet

2 hours ago, aeh5040 said:

I have found that one effective way of reducing noise is to isolate the motor mechanically so that there is less transmission of vibration to surrounding parts and to the table (if the model is on a table).  Rubber parts can be useful for this.

...and made it authentic to a real-life car that also has such rubber isolation on the engine mounting points. So, it looks like a next step after disk brakes, McPherson's suspension, sequential gearbox, pneumatic engine and other advanced things that moves Lego MOCs closer and closer to a full replica or real-life vehicles. 

5 hours ago, itoero said:

I think you can compare it with a driving car.

If it's dry, then there will bea lot of  noise because of friction between the tires and the asfalt.

If it's snowy then there can be a layer of snow (can work like a layer of grease) between the asfalt and the tires which reduces friction and noise and reduces the power the tires have on the asfalt.

By reducing friction I think you reduce noise and power but you lengthen the battery life.

That is true for a system that uses friction to transfer energy, like the tires on a car. In a system that uses gears, like inside the xl motor, friction is bad. Decreasing friction will increase the amount of power available, and should lengthen battery life.

 

My xl motors are noisier than my other motors.

Are you sure it's not sound from PWM speed regulation?

11 hours ago, Void_S said:

...and made it authentic to a real-life car that also has such rubber isolation on the engine mounting points. So, it looks like a next step after disk brakes, McPherson's suspension, sequential gearbox, pneumatic engine and other advanced things that moves Lego MOCs closer and closer to a full replica or real-life vehicles. 

As a very simple practical step, I have started using these rubber parts as "feet" on the bottom of stationary motorized models (which most of mine are).  In addition to reducing noise, they stop it sliding around. 

Edited April 25, 20177 yr by aeh5040

There are polymer/rubber sprays...can such a coating reduce noise?

21 minutes ago, itoero said:

There are polymer/rubber sprays...can such a coating reduce noise?

I took mine apart and sprayed the inside with Lithium grease, they are noticeably quieter now. The stock ones only come with the smallest amount of grease and they causes most of the noise.