PEM, motor gets too hot -- fans failed

[cinergi]

To me the new sound sounds like a stepper-motor operating at high frequency. Before, I used to just hear air. Now I hear a motor and if it's going fast enough, motor + air. At this point, I don't think I've gotten it hot enough for it to come on at full speed, but I do find it louder both inside and outside the car. To hear it inside the car, I have to be traveling at less than about 30MPH. I don't hear it on the highway. For initial testing, I put the car into performance and floored it on the highway until 100-105 a couple of times (to which the tech said "Tesla's gonna look at the logs I have to pull after this and think it was me who drove 100 MPH!" LOL). I got the motor up to the third temp notch and the PEM never went past the third notch. The fan was definitely running for a while to cool down the motor (the PEM nearly instantly cooled off to the first bar). I've also heard it come on for charging (60F ambient in the garage) ... I wish I had before and after audio. Oh well.

BTW, it's definitely variable speed. You can hear it stepping down the speed as things cool down.

I found the rotor relatively difficult to move (for a motor). It definitely doesn't freely spin with the flick of a finger.

 

[hcsharp]

Do you use hearing aids? They (or your own hearing) might be responding to different frequencies.

Yes I wear advanced digital hearing aids that respond to different types of sound very differently depending on the environment. That may account for my opinion. Maybe it's colder here so I never had the fan running at a higher setting. I'm fairly sensitive to noise like those fans because it prevents me from hearing speech. My wife (excellent hearing) thought it was a little quieter. The Tesla Tech said one of the benefits was that it is quieter. Might be one of those things where "your mileage may vary."

 

[Doug_G]

To me the new sound sounds like a stepper-motor operating at high frequency. Before, I used to just hear air. Now I hear a motor and if it's going fast enough, motor + air.

It's very unlikely to be a stepper motor, because there aren't enough pins on the connectors. Also my Ranger said there were diodes in the cables. This strongly suggests a DC motor.

BTW, it's definitely variable speed. You can hear it stepping down the speed as things cool down.

I've only heard it running on low speed during charging. Even though today was mild by winter standards, temperatures were still below freezing and I wasn't able to crank it up.

Does the motor pitch change with speed? I'll bet it doesn't - it's very likely a DC motor with PWM (Pulse Width Modulation) for speed control. If so the hum is probably the motor windings vibrating from the pulsing magnetic forces. People reporting different sound level is probably due to random variations in the motor windings and varnish. Some motors are inevitably louder than others.

I suspect mine is pretty loud; it's certainly not subtle. My first impression of the sound was, frankly, "annoying". Here's a nice quiet electric car with this awful hum coming out of the back. Maybe it'll settle down after operating for a while (wishful thinking?), but I'm going to want to listen to some other Roadsters for comparison.

 

[Dragon]

I confirm that it's variable speed. I confirm finding it "annoying" at first impression as well. However didn't pay attention about it the last times I drove and didn't hear anything disturbing.

 

[Eberhard]

I confirm that it's variable speed. I confirm finding it "annoying" at first impression as well. However didn't pay attention about it the last times I drove and didn't hear anything disturbing.

i confirm

 

[dsm363]

Did everyone get it as a free upgrade? I called the Chicago service store and they said it was a paid upgrade for me. I haven't had any problems necessarily but having a fan that cooled the PEM and motor better would be nice in the heat.

 

[Doug_G]

Did everyone get it as a free upgrade? I called the Chicago service store and they said it was a paid upgrade for me. I haven't had any problems necessarily but having a fan that cooled the PEM and motor better would be nice in the heat.

I'm surprised since Chicago has fairly harsh winter weather. Just wait for your existing fan to fail - it almost certainly will - and they'll have to do it under warranty anyway.

For Canada they decided to replace everyone's fans, because they were spending a lot of time traveling around doing free warranty replacements anyway. I was already on my second set.

Alternatively, maybe contacting your customer advocate would help.

 

[hcsharp]

Did everyone get it as a free upgrade? I called the Chicago service store and they said it was a paid upgrade for me. I haven't had any problems necessarily but having a fan that cooled the PEM and motor better would be nice in the heat.

Just spray some salty water in the fan bearings every day until they fail.* It won't take long.
Then call for warranty service.:biggrin:


*not actually suggesting you do this...

 

[dsm363]

I'm in Texas so I guess the only way it would likely break is if I drive on a lot of dusty roads which I don't. I kind of feel that this is something they should fix anyway if it's a know issue. If I ever move back up north after the warranty expires, I would need to be replace then and at that time, it would be out of warranty.

 

[strider]

I'm in Texas so I guess the only way it would likely break is if I drive on a lot of dusty roads which I don't. I kind of feel that this is something they should fix anyway if it's a know issue. If I even move back up north after the warranty expires, it would need to be replace then and at that time, it would be out of warranty.

That is lame. It's a design problem and they should retrofit everyone's. As I said earlier I live in a quite mild climate but I had reduced power and loss of AC a few times last summer.

 

[dsm363]

That is lame. It's a design problem and they should retrofit everyone's. As I said earlier I live in a quite mild climate but I had reduced power and loss of AC a few times last summer.

I agree. I don't think I had the reduced power but with the heat in Texas, I did have the AC cut out from time to time.

 

[hcsharp]

That is lame. It's a design problem and they should retrofit everyone's. As I said earlier I live in a quite mild climate but I had reduced power and loss of AC a few times last summer.

I'm pretty sure that loss of AC is due to battery overheating, not PEM or motor.

 

[Eberhard]

That is lame. It's a design problem and they should retrofit everyone's. As I said earlier I live in a quite mild climate but I had reduced power and loss of AC a few times last summer.

even the new design for the PEM blower is a poor solution. Better would have been a liquid cooled PEM. No more problems with debris as well. Higher heat capacity allows longer engagement of full performance mode. More compact and less energy consumption. that is the reason, why Model S power train is full liquid cooled.

 

[JRP3]

Yes but I don't see them redesigning the PEM just for the Roadsters which are no longer in production.

 

[WarpedOne]

Even the new design for the PEM blower is a poor solution. Better would have been a liquid cooled PEM. No more problems with debris as well. Higher heat capacity allows longer engagement of full performance mode. More compact and less energy consumption. that is the reason, why Model S power train is full liquid cooled.

Yes, liquid cooling offers higher average power but it comes with higher weight and complexity, higher reliability issues and bigger space requirements. Engineering is seldom clearcut business.
And liquid cooling still needs fans and pumps that eat power.

 

[cinergi]

It's very unlikely to be a stepper motor, because there aren't enough pins on the connectors. Also my Ranger said there were diodes in the cables. This strongly suggests a DC motor.

Agreed - just sounds like one (analogy to describe the noise it makes).

My new fan seems to have picked up a problem :-( sounds like there's something stuck in the blades and it's also squealing (similar to the squealing noises prior to the old fans failing). Ugh.

 

[W.Petefish]

I agree. I don't think I had the reduced power but with the heat in Texas, I did have the AC cut out from time to time.

I have had the power limited light come on almost every day during summer. (and my first fan change at 6 months) This solution is, I think, only a stop-gap until they make a filter for it. A higher power fan would help though. I'll ask Ranger Larry today about it as he is working on mine.

 

[Eberhard]

Yes, liquid cooling offers higher average power but it comes with higher weight and complexity, higher reliability issues and bigger space requirements. Engineering is seldom clearcut business.
And liquid cooling still needs fans and pumps that eat power.

you are right, except the space issue. liquid cooled systems are more compact and you can dislocate the outer cooling system.

 

[WarpedOne]

Dislocation still requires space. There is none available in Roadster.

 

[Eberhard]

the whole cabinet underneath of the trunk is used to host both blowers. The whole surface of the cars bottom can be used for a passive cooling. the liquid is only used to transport the heat from the PEM/Motor to the heat-sink. only a small liquid-pump is needed. with liquid cooling, you can even increase the size of the trunk. air is a poor coolant. you need huge volumes of air which require large diameters for the air pipes and large areas of heat-exchangers.