Electric motor sound

[Gohcl]

Hi all

I would like to check what make he sound of electric motor sound like jet engine?
YouTube link to electric motor sound -

http://youtu.be/OzS-ITrE4lo

I am actually having a Washing machine at home and during the final spin there is a jet engine sound. Even when I go to my friends house, all machine is the same. Hence I am curious how the sound come about. I try search online and doesn't find any thing related to it only electric motor. But how does it make the sound? Is it by air flowing through the fan motor? But it doesn't seems like there is fan motor for washing machine motor.

Hope someone can help me and clear my doubt. Been searching for many days.
Thanks in advance

 

[MikeHalloran]

There is almost certainly a fan within your washing machine's motor.
It is normal for a motor to make a little fan noise at or near its maximum speed.
It is possible that different washing machine makers use different motors, and adopt different strategies for controlling or suppressing noise.

If you can find another washing machine that is _exactly_ like yours, and yet makes a different noise, then you may have a problem. ... probably not.


Mike Halloran
Pembroke Pines, FL, USA

 

[Gohcl]

Hi mike

Thank you for your reply.
Am I correct to say that all electric motor contain a fan or something to cool the motor. With this, as air pass through the fan in high speed it produce the engine sound. Something similar as jet engine aircraft when air passes through.

I saw some washing machine doesn't seems like there is fan on their motor. eg LG direct drive motor. I saw only stator and rotor. Unless the behind rotor casing got some hole is for air to enter and to cool it.

 

[BrianPetersen]

I wouldn't say that "all electric motors contain a fan", but it is fair to say that "all electric motors designed for continuous use have a means of cooling", and that is frequently a fan. But if the motor is connected with a good thermal conduction path to something else that can act as a heat sink, it might not have a fan.

Washing machines usually have plenty of water going through them. (Hint.)

 

[Gohcl]

Hi
Thanks for the info. But why does washing machine have plenty of water going though the electric motor. It is not a water pump. Only for drain pump.
Actually my main concern is how does the engine sound car like. Previously my conclusion is having a cooling fan. And cooling fan at high speed products this sound. I also search online about cooling fan at high speed and indeed is jet engine sound. But I notice some washing machine design are using direct drive which there is any fan and I believe is like what you mention, have a mean of cooling. And with this mean there is air flow passing through it from the inside to the outside. Hen again at high speed the sound appear again.
Btw what you mean by good thermal conduction path? Any example? Thanks for the help.

 

[BrianPetersen]

A picture of the motor that you are wondering about, including what it is attached to, would help a lot.

For a washing machine that is made in large numbers, you can be certain that the cheapest possible motor configuration that the manufacturer can get away with, is what the machine has.

 

[theode]

As well as fan noise,there are also other mechanics in the mix.
Even the ẃindings of the motor give off an electrical hum.
Add to that the driven components (drum,pumps etc) and associated bearing surfaces,it can get a bit noisy.
A 'dry' bearing spinning at over 3000 rpm can sound like a 747 taking off .
Plus the casing of the washing machine can amplify the noise.

 

[Gohcl]

Hi

I have attach the picture of Lg direct drive motor. This is the part of my concern where how the jet engine sound came about.

 

[Gohcl]

Hi

Below YouTube link for the engine sound that I am very curious with of how it came about

http://youtu.be/5nboONIMetA

Link copy using iPhone. Btw so this sound is came from
Bearing and not the air flowing pass the cooling fan ?

 

[itsmoked]

Modern washing machines use VFDs to spin smaller motors very fast. They then use s single serpentine belt to the drum drive. The motors are spun up to over 20,000RPM which is approaching turbine speeds. You can be hearing the fan but you could also be hearing the VFD modulation in the windings.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

The bearing that supports the drum may be failing.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[BrianE22]

Try blocking the air flow from the motor's fan. You'll only be able to run for a short time without overheating but if the air flow is noisy you should be able to hear a difference.

 

[Gohcl]

Hi all

Thanks for all the support.
At least my conclusion is that the jet engine sound come from fan.
Or air moving pass high speed stationary object will generate this jet engine sound. Secondly is maybe bearing at high speed also create the jet engine sound.
Although the i can't find any article on this. But through all the post above. I believe this is the answer.

 

[cswilson]

Many modern washing machines use a switched reluctance (SR) motor under electronic control. SR motors use a salient (protruding) pole design, where the physical rotor protrusions pass very close to the stator poles with sub-millimeter clearance. (To a first approximation, if you can cut the aligned clearance in half, you can double the torque from the motor.) In between the protrusions, there is a huge air gap.

As the motor spins, these rotor protrusions pass very closely by the stator poles, pushing the air out of the way. After it passes by, air rushes in again to fill the gap. (This does not happen in the permanent magnet motor design you showed.) At the high speeds of the spin cycle, this happens quickly and often, and it can be very loud. High acoustic noise from SR motors operating at high speeds is a common complaint in consumer applications. But they are inexpensive!

 

[MikeHalloran]

How about a photo of the motor in _your_ washing machine, so we are not speculating about the entire global population of motors?


Mike Halloran
Pembroke Pines, FL, USA

 

[Gohcl]

Hi

The motor look something like this as attach. The picture is I found online on the supplier website.

 

[zzzjim]

With belt driven drums , the hi rpm of the motor can be rather hi pitched ,for those who still have good hearing . Motor spins many more times than rpm of drum. Plenty of carbon dust about is a clue to how many sets of brushes have been eaten
(2nd picture -9th Jan - not a direct drive !)