# Warp 9 problem, shaft slipping?



## Ziggythewiz (May 16, 2010)

Haven't watched the video, but from the description it sounds like when my shaft coupler died. Under light load and low speed it would still hold, but more and the teeth could grind past each other. Eventually it just slips all the time.

Pulled the motor and the teeth on the coupler were ground shorter than they should be and lots of metal dust inside.


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## rwaudio (May 22, 2008)

swoozle said:


> I've got a problem with a Warp 9 slipping during acceleration that I have thought was the clutch slipping, but now I don't think it is.
> 
> So: Has anyone had a problem with the armature slipping on the shaft? Are there other problems that act the same?
> 
> ...


Sounds a bit like controller noises through the motor. Try changing some settings in the controller to see what affect it has. If the armature windings were slipping on the shaft it probably would have blown up from spinning too fast.


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## mk4gti (May 6, 2011)

Had a similar problem, the clutch was not positioned correctly on the tranny (input?) shaft... It was first doing something just like your video then I got stranded... doh!

Try adjusting the clutch cable but if that doesn't work, it's time to pull the motor I'm afraid


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## swoozle (Nov 13, 2011)

Ziggythewiz said:


> Haven't watched the video, but from the description it sounds like when my shaft coupler died. Under light load and low speed it would still hold, but more and the teeth could grind past each other. Eventually it just slips all the time.
> 
> Pulled the motor and the teeth on the coupler were ground shorter than they should be and lots of metal dust inside.



Thanks for the response. It's a CanEv keyed/set screw'd coupler so I don't think that's it. I'd see any slipping there as an increase in measured RPM (plus once the key was sheared it would slip constantly).


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## swoozle (Nov 13, 2011)

mk4gti said:


> Had a similar problem, the clutch was not positioned correctly on the tranny (input?) shaft... It was first doing something just like your video then I got stranded... doh!
> 
> Try adjusting the clutch cable but if that doesn't work, it's time to pull the motor I'm afraid


I've done that once to replace the clutch. Nothing unusual was seen. The clutch works fine and has for the past 800 miles (I forgot to mention that!).


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## swoozle (Nov 13, 2011)

rwaudio said:


> Sounds a bit like controller noises through the motor. Try changing some settings in the controller to see what affect it has. If the armature windings were slipping on the shaft it probably would have blown up from spinning too fast.


What should I change? I'm running a P&S controller board with an IGBT power stage. I get a higher pitched whine from the controller all the time. This is a relatively low-pitched sound compared to that. 

I can easily pull 800 amps without seeing this "event" if I do it at slightly higher rev where the torque isn't quite so high. It's when I stomp on it low in a gear that this occurs, even at relatively low (~500) amps.

Thanks


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## z_power (Dec 17, 2011)

I'd remove screen/band covering brushholder, this should give enough access to paint some markings on the armature or "unused" part of commutator; next step would be comparing alignment of these marks with tailshaft keyway bafore and after test run (and letting us know the results )
I put some marks on my transmission coupler before assembly - it's not keyed, uses just taper lock friction, I can check for slipping with flashlight trough factory hole in bellhousing.


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## major (Apr 4, 2008)

swoozle said:


> I can easily pull 800 amps without seeing this "event" if I do it at slightly higher rev where the torque isn't quite so high. It's when I stomp on it low in a gear that this occurs, even at relatively low (~500) amps.


The motor torque is independent of RPM. Torque is the same at 800 amps at low revs or high revs.

I've seen rotors slip on the motor shaft in ACIM; never on a DC motor. It is highly unlikely. Both the stack and commutator would have to slip and not move relative to each other. It is almost inconceivable that could occur without causing a short in the armature coils or gross distortion of the commutator itself.

But to convince yourself, try it with a locked motor shaft or locked wheels. Give it a quick shot of 800 amps and see it the comm rotates on the stationary motor shaft. Do not apply current to the non-rotating comm for longer than a second or you'll damage it (burn or lift some comm bars.) 

You know guys drag race the Warp9. They use up to 2000A. Ever heard of a slipping armature from any of those guys? Nope


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## rwaudio (May 22, 2008)

swoozle said:


> What should I change? I'm running a P&S controller board with an IGBT power stage. I get a higher pitched whine from the controller all the time. This is a relatively low-pitched sound compared to that.
> 
> I can easily pull 800 amps without seeing this "event" if I do it at slightly higher rev where the torque isn't quite so high. It's when I stomp on it low in a gear that this occurs, even at relatively low (~500) amps.
> 
> Thanks


Can you adjust the motor voltage/current?

Basically if you change a setting and it affects the sound it could be related to the motor/controller interaction.

What frequency does the controller operate at?
Does it drop to a lower frequency under certain conditions?

My Soliton1 for example will drop from the "quiet" frequency to the "performance" frequency under certain normal operating conditions when it's set to quiet mode.

I haven't kept up on the P&S details but it could be something similar.


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## onegreenev (May 18, 2012)

Many stock pressure plate and clutch setups can't handle the high torque of the electric motor. Even slightly higher pressure of Stage I pressure plates usually are not enough. I use a Stage II and I have seen an electric motor smoke a Stage II. Its 220 ft lb. It is fine for average street use but if your not careful you'll smoke it. Your Stage I will more than likely be 180 or under. Stage IV for the VW is upward of 300 ft lb pressure. Electric motors can even surpass that. 

Pete


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## onegreenev (May 18, 2012)

Im going to say hands down its your clutch slipping.


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## swoozle (Nov 13, 2011)

onegreenev said:


> Many stock pressure plate and clutch setups can't handle the high torque of the electric motor. Even slightly higher pressure of Stage I pressure plates usually are not enough. I use a Stage II and I have seen an electric motor smoke a Stage II. Its 220 ft lb. It is fine for average street use but if your not careful you'll smoke it. Your Stage I will more than likely be 180 or under. Stage IV for the VW is upward of 300 ft lb pressure. Electric motors can even surpass that.
> 
> Pete


Ya, this is why I've been assuming that it was the clutch all along. But I also know that you can see clutch slip in the tach read, just like wheel slip. The engine over-revs and then snaps back when it re-engages. I'm seeing nothing like that.



z_power said:


> I'd remove screen/band covering brushholder, this should give enough access to paint some markings on the armature or "unused" part of commutator; next step would be comparing alignment of these marks with tailshaft keyway bafore and after test run (and letting us know the results )
> I put some marks on my transmission coupler before assembly - it's not keyed, uses just taper lock friction, I can check for slipping with flashlight trough factory hole in bellhousing.


Now THIS is what I was looking for! Thanks for the idea. This will rule out armature slip once and for all.



major said:


> You know guys drag race the Warp9. They use up to 2000A. Ever heard of a slipping armature from any of those guys? Nope


Uh, yeah, I'm aware of that. IF the armature is slipping, there is something seriously defective in the motor. That's not impossible: like any manufactured part, occasionally there are errors in making them. There are other threads about other problems with these motors. 

But again, I'm asking for theories and ways to prove/disprove them. I'm not saying it is definitely the armature slipping. I'd much rather it be the clutch. That's easy (though increasingly spendy) to fix.



rwaudio said:


> Can you adjust the motor voltage/current?
> 
> Basically if you change a setting and it affects the sound it could be related to the motor/controller interaction.
> 
> ...


RW, thanks for the feedback, but I'm going to slot that a little down the probability list. If you could hear/feel this in person I think you would agree that it is probably a mechanical issue and not an electronics one.


Thanks for the help, guys!


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## onegreenev (May 18, 2012)

Loose taper lock would behave like a slipping clutch but may sound quite different. Hard to diagnose from the video. You really should remove the motor and check your taper lock and clutch.


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## rwaudio (May 22, 2008)

swoozle said:


> RW, thanks for the feedback, but I'm going to slot that a little down the probability list. If you could hear/feel this in person I think you would agree that it is probably a mechanical issue and not an electronics one.


The video likely doesn't do it justice, however being an audio guy it simply sounds more like harmonics generated by the motor than a mechanical slip. Good luck though, I'm sure you'll get to the bottom of it!
If I was in your place I would hope it's mechanical as well since it would likely be much easier to fix, or at least have a cut and dry solution.


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## skooler (Mar 26, 2011)

May I suggest some tipex marks on the motor shaft (tail shaft?) and some on the rotating mass. Perhaps a insulating varnish instead in case tipex burns up or something but you get the idea!

If they move then its slipping. Simples!

I bet its the clutch though 

Good luck


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## swoozle (Nov 13, 2011)

onegreenev said:


> Loose taper lock would behave like a slipping clutch but may sound quite different. Hard to diagnose from the video. You really should remove the motor and check your taper lock and clutch.


Thanks, but it's not a taper-lock, it's set screw and key. And ya, I didn't forget the key.



swoozle said:


> RW, thanks for the feedback, but I'm going to slot that a little down the probability list. If you could hear/feel this in person I think you would agree that it is probably a mechanical issue and not an electronics one.


Well this ranking didn't last long! I tried marking the armature and tach sensor collar and they didn't move relative to each other one iota. The (admittedly far-fetched) armature slipping theory is definitely out.

I did more runs and that tach reading is ROCK solid, unlike a clutch slip would be. If it was the clutch, I'd also expect the response to have changed significantly with a new clutch or at least get worse with wear as I keep pushing it. I'm back to your electronics theory, Robin.



rwaudio said:


> The video likely doesn't do it justice, however being an audio guy it simply sounds more like harmonics generated by the motor than a mechanical slip. Good luck though, I'm sure you'll get to the bottom of it!
> If I was in your place I would hope it's mechanical as well since it would likely be much easier to fix, or at least have a cut and dry solution.


Here's another video. The controller runs at 8khz and you can clearly hear that high-pitched whine when the buzz isn't drowning it out. The buzz is much lower frequency and a lot louder. What do you think?




The new plan is now to go look at the Open Revolt control parameters and see what makes sense to tweak. I also need to connect RTD Explorer and see what that shows me is happening in the controller during these events.
Do any of you Open Revolt experts have any suggestions? Paul, are you out there?

Lastly, I've got a ceramic puck clutch disk coming. When that comes I'll pull the motor to install it and see what I can see on the mechanical side.

Thanks everyone and please let me know if you have other thoughts.


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## Zappo (Sep 1, 2011)

I've played the videos over and over. The closest that sounds like to me is a few times what I've seen with industrial motors where the outer race of a motor bearing was actually spinning in the housing at times.

At this point, it is a real mystery. If it had been a bad clutch, you should have seen some signs of that when you tore it down the first time. I'd also be very surprised to get exactly the same results with two different clutch plates. Other than that, I would strongly suspect the clutch also.


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## rwaudio (May 22, 2008)

Ok I finally figured out where I had heard a motor make that type of noise before. After I built my CNC router and I was still tuning the stepper motors for acceleration/speed etc they would make noises a bit like that (not exactly) when they would stall or miss steps. Your warp is an entirely different beast operating in a totally different way but I still bet on it being some sort of interaction between the motor and controller when you try to reach that current level.

I'm not sure what the P&S firmware is like but can you tweak the slew rate of the current? It likely wouldn't solve the problem but it would change the "tune" and might help you get to the bottom of it.

How many others are using an IGBT version of that controller?


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## mora (Nov 11, 2009)

I have P&S controller too (mosfet-based) and am hearing these exact same sounds from time to time. My motor is 9" Kostov though. It doesn't seem to do any harm other than being loud. Clutch slip is very quiet compared to this noise and is clearly shown on rpm meter. It is not Curtis whine style either. Currently I have all the sound proofing removed. Symptoms are the same: at really low rpm motor "sings" when I floor the throttle pedal. When rpm increases the frequency lowers, just like in your videos. After certain rpm it goes away completely. That's even if amps stayed the same.

I didn't have this singing before. It began during summer when I derated my controller down to 400A from 500A. I believe it is controller based thing, maybe over current protection related? You should post these video links to Paul Holmes too.

Brushless motors used in rc-planes and helicopters can also "sing", even when stationary. Speed controllers can make them "sing" and it is usually used to notify user about different settings at startup. But there it is made on purpose. Any other singing sounds often relate with timing issues.

Sorry, your last video made me laugh. I haven't had that funny sequence coming out of my motor, at least yet.


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## swoozle (Nov 13, 2011)

mora said:


> I have P&S controller too (mosfet-based) and am hearing these exact same sounds from time to time. My motor is 9" Kostov though. It doesn't seem to do any harm other than being loud. Clutch slip is very quiet compared to this noise and is clearly shown on rpm meter. It is not Curtis whine style either. Currently I have all the sound proofing removed. Symptoms are the same: at really low rpm motor "sings" when I floor the throttle pedal. When rpm increases the frequency lowers, just like in your videos. After certain rpm it goes away completely. That's even if amps stayed the same.
> 
> I didn't have this singing before. It began during summer when I derated my controller down to 400A from 500A. I believe it is controller based thing, maybe over current protection related? You should post these video links to Paul Holmes too.
> 
> ...


Bingo! I emailed Paul last night and that's what he said: hardware over-current limit kicking in. I'd already maxed out on adjusting the limit via VR1 pot, so I increased the spacing between the melexis current sensor and the busbar. The noise doesn't occur as readily now but still occurs. I'm going to space it a little further. That's the green current sensor mid-pic.








It's a little surprising how loud the singing is. Does anyone know what's vibrating to make it sing?

Thank you all very much for your help, particularly to RW for identifying the real problem and his patience in convincing me!

PROBLEM SOLVED


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## mora (Nov 11, 2009)

Cool, thanks for posting. I'm at the other end of VR1. I set it to minimum and motor current is reduced to 400A. I'm trying to protect my 9" Kostov as it isn't really made for high currents.


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## major (Apr 4, 2008)

swoozle said:


> Thanks everyone and please let me know if you have other thoughts.


Well, that video sounds a lot like my old eJeep which has an SCR controller. Very low frequency chopper. And it is direct drive, so no clutch or anything mechanical to slip. So I'd say it is your controller cutting back in a limit mode, like current limit.

edit: Sorry, I composed this and went to lunch, came back and posted without seeing the Problem Solved. Anyway, good for you. I didn't think that shaft slipped.


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## rwaudio (May 22, 2008)

swoozle said:


> PROBLEM SOLVED


Glad to hear it!

Maybe you can tweak the software/throttle response to play a tune while you drive!!


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## jyanof (Nov 11, 2008)

swoozle said:


> Bingo! I emailed Paul last night and that's what he said: hardware over-current limit kicking in. I'd already maxed out on adjusting the limit via VR1 pot, so I increased the spacing between the melexis current sensor and the busbar. The noise doesn't occur as readily now but still occurs. I'm going to space it a little further. That's the green current sensor mid-pic.


Just wanted to add that the hardware overcurrent protection will probably kick in sooner (be more sensitive) at 8 khz than 16 khz. The switches are on for a longer amount of time during each PWM cycle which allows the motor current to ramp up higher (and then ramp down lower when the switch is off). I think I noticed the same thing when I was testing out the 8khz software.

edit - i'm not suggesting that you change the switching frequency, btw. i'm betting you chose 8khz for the IGBTs, but just pointing out another factor that could be contributing to the abnormal behavior.


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## swoozle (Nov 13, 2011)

jyanof said:


> Just wanted to add that the hardware overcurrent protection will probably kick in sooner (be more sensitive) at 8 khz than 16 khz. The switches are on for a longer amount of time during each PWM cycle which allows the motor current to ramp up higher (and then ramp down lower when the switch is off). I think I noticed the same thing when I was testing out the 8khz software.
> 
> edit - i'm not suggesting that you change the switching frequency, btw. i'm betting you chose 8khz for the IGBTs, but just pointing out another factor that could be contributing to the abnormal behavior.


That makes sense, thanks. I'd been wondering why the limit had been kicking in when the indicated current wasn't that extreme.


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