# Engine squeal



## Yukon_Shane (Jul 15, 2010)

I'm getting this very slight motor squeal in my warp 9 when it first starts/stops spinning. It seems to go away as soon as the rpm come up at all. I'm not sure whether it's coming from the front or the back of the motor. It seems to have started about a week after I started driving the car.

To be clear, this is seperate from the "singing" sound associated with the controller frequency; this is a distinct high piched sound that sounds like a bearing needs to be greased or something.

Does anyone else have a sound like this?

Any thoughts on what it might be?


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## Woodsmith (Jun 5, 2008)

Are you able to spin it by hand and listen for squeaky noises?

I would suspect a bearing but it could also be something rubbing on a rotating part either inside the motor or the coupler.

Do you still have the clutch? It could be from the clutch springs or the release bearing, or just dirt or something in the bellhousing.


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## Yukon_Shane (Jul 15, 2010)

Woodsmith said:


> Are you able to spin it by hand and listen for squeaky noises?
> 
> I would suspect a bearing but it could also be something rubbing on a rotating part either inside the motor or the coupler.
> 
> Do you still have the clutch? It could be from the clutch springs or the release bearing, or just dirt or something in the bellhousing.


I'll try turning the motor by hand and see if I can better identify the sound. 

It sounds like a bearing to me but the motor is new so I wouldn't think the bearings would be worn out yet.

I don't have a clutch so it can't be anything there but could be the coupler rubbing against the motor. I guess I should just take the motor out and take a look at the coupler/transmission end. I just thought I'd touch base with the folks here first to see if this kind of noise is common before I went through all that work. I'd hate to tear a motor out just to find out that the answer is as simple as spraying a little WD40 on the front bearing


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## Woodsmith (Jun 5, 2008)

Don't use WD40, it will remove any lube that is there.

Also check for end float. The armature, or the coupler, could be moving axially very slightly and rubbing a bit before settling down.
The coupler should be fixed to the armature and free to float on the transmission shaft.


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## ruckus (Apr 15, 2009)

Yukon_Shane said:


> I'd hate to tear a motor out just to find out that the answer is as simple as spraying a little WD40 on the front bearing


Don't spray it with WD40! The bearings are sealed, right? (somebody please correct me if I'm wrong) wd40 will just attract dust and turn it into gunk. wd40 is GREAT for restoration of dino burners like this here:


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## ruckus (Apr 15, 2009)

double post somehow... sorry


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## O'Zeeke (Mar 9, 2008)

i had a squeaking noise which i noticed shortly after i started driving my warp11 bach when it was new,more noticeable after it warmed up some. I was convinced it was a bearing so i shipped it back to warfield where it was not bearings but rather the brushes. Took a few thousand miles but went away completley


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## Yukon_Shane (Jul 15, 2010)

O'Zeeke said:


> i had a squeaking noise which i noticed shortly after i started driving my warp11 bach when it was new,more noticeable after it warmed up some. I was convinced it was a bearing so i shipped it back to warfield where it was not bearings but rather the brushes. Took a few thousand miles but went away completley


Funny that you mention that because the sound seems to become noticible as the motor warms up and I was just wondering if it might be the brushes breaking in. 

I have to admit to not doing any real break-in proceeder with this motor. Their seams to be no real consensus on what is required.

The car is running great and my "milleage" isn't decreasing at all so maybe I'll just drive it for awhile and see if the noise goes away.

thanks O'Zeeke


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## Tesseract (Sep 27, 2008)

Yukon_Shane said:


> ...
> I have to admit to not doing any real break-in proceeder with this motor. Their seams to be no real consensus on what is required...


Sure there is a consensus on brush break-in, at least among those with knowledge and experience on the matter (e.g. - major).

If you have a working tach sensor and a Soliton then you can use the idle function to make break-in painless. Set idle to 1000 rpm, put the transmission into neutral, and let the motor spin for at least 8 hours, though more is better up to, say, 30 hours. You can break this up into several sessions just don't drive the car in between sessions or you will have to start over again.

In addition, make sure the current through the motor while idling is around half the stated 1 hour rating (this will be ~100-150A for a typical 9" motor). This helps to build up a nice film on the commutator without risk of overheating because of the low RPM.

Don't forget to keep the battery pack charged - it usually doesn't take much power to idle the typical EV with the transmission in neutral, but it's certainly not zero - anywhere from 1.5kW to 5kW is typical, depending on the driveline efficiency, number of accessories hanging off the tailshaft (particularly the power steering pump), etc. I suggest running Logger every hour to see exactly how much power is required (multiplying motor current, pack voltage and duty cycle) as the number should drop somewhat over time.


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## ruckus (Apr 15, 2009)

So you have had good results at high voltage/low load? 

Most folks seem to recommend 12v for break in, but maybe that is only to avoid overspeed and it is the low-load part that is significant. 

Any controller with rev limiting could be used in a similar way. Set the rpm limit down to 1000 and then put a brick on the go pedal.


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## Yukon_Shane (Jul 15, 2010)

Tesseract said:


> Sure there is a consensus on brush break-in, at least among those with knowledge and experience on the matter (e.g. - major).
> 
> If you have a working tach sensor and a Soliton then you can use the idle function to make break-in painless. Set idle to 1000 rpm, put the transmission into neutral, and let the motor spin for at least 8 hours, though more is better up to, say, 30 hours. You can break this up into several sessions just don't drive the car in between sessions or you will have to start over again.
> 
> ...



That seems easy enough. So essentially what I'm trying to do is shape the brushes to the commutator and build a film from the brushes onto the commutator?

Should this proceedure result in more efficient operations or is it more about brush longevity?

I'll search through major's posts and see if I can find a reference to this. That guy definitely knows what he's talking about when it comes to motors.

Thanks Tess


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## major (Apr 4, 2008)

Yukon_Shane said:


> So essentially what I'm trying to do is shape the brushes to the commutator and build a film from the brushes onto the commutator?
> 
> Should this proceedure result in more efficient operations or is it more about brush longevity?


Yes, yes and yes. The proper brush seat and comm film reduces friction, reduces contact voltage drop and therefore reduces heat. This increases motor efficiency. It will reduce wear rate of both the brush and commutator.

This process of brush seating and commutator film (patina) requires running the motor (RPM, current, voltage). It is impossible to quantify a time requirement because it depends on so many factors like comm surface finish, brush grade, atmospheric conditions, current and voltage level, surface speed, spring force and sunspot activity. Usually it is somewhere between 20 and 1000 hours  

This film is golden in my opinion. If treated as such, your motor will serve you well for many years. It is a fragile thing which can be contaminated especially with oil. Also it can be stripped with excessive current or arcing. Even excessive low humidity can cause problems.

For the usual EV motor break-in, I suggest running at 12V for several days (8 to 10 hours/day). Because current is required, I like to have the motor in the car with the wheels jacked up. This puts a moderately low load on the motor, maybe like 75A on a Warp9. It also breaks-in the tranny and drivetrain. Strange as it may seem, the motor can overheat, so put a fan blowing air across it and keep an eye on it. This should start the comm film. Take it easy driving for the first few hundred miles. No 2000A drag races  right away.

That should get you into the zone for good motor efficiency and life.

major


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## Yukon_Shane (Jul 15, 2010)

major said:


> Yes, yes and yes. The proper brush seat and comm film reduces friction, reduces contact voltage drop and therefore reduces heat. This increases motor efficiency. It will reduce wear rate of both the brush and commutator.
> 
> This process of brush seating and commutator film (patina) requires running the motor (RPM, current, voltage). It is impossible to quantify a time requirement because it depends on so many factors like comm surface finish, brush grade, atmospheric conditions, current and voltage level, surface speed, spring force and sunspot activity. Usually it is somewhere between 20 and 1000 hours
> 
> ...


Well this post saves me alot of searching. I appreciate it, particularly as I imagine it's a topic that you've probably responded to many times already.

Thanks

Shane

Ps if 2000 amps is ever coming out of my battery pack something's gone terrible wrong


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