Motor + ESC running problems

[swbluto]

Okay, so I have had disconnects before in the past between the motor and the ESC. Disconnecting one phase wire seemed to make a characteristic click+rumble sound and the motor just rocks back and forth. After recent testing, disconnecting two or more phase wires means the motor doesn't run at all - makes sense, since it takes at least two phase wires to tango.

But, recently, I've been getting an oddly simplistic clicking sound. There's no characteristic rumbling like when simply one phase wire is disconnected. Any ideas on what it could be?

I ran some more tests and ran a 20 gauge alligator clip in between the motor leads trying to "short it", thinking that two phases might've been shorted or something. The motor still ran, though at a less speed and with less power. It felt like the 20 gauge wire was getting warm but then I realized I wasn't really "shorting the motor" - the motor coil resistance is pretty small to begin with since the effective wire gauge through the motor isn't thinner than 12 gauge, so I was only sapping some power from two phase combinations (not including the direction of current). Anyways, I'll have to devise a way to more directly test that...

I also pulled the motor wires back and forth from two characteristic positions (The motor wires are 4 feet long) and it seemed in *this* position, the motor always started and ran fine but in this *that* position, it didn't. I'm running anderson powerpoles that then go through some banana plugs (Hobbycity gold-plated bullet plugs), so has anybody had similar symptoms with those? I think I just might be accidentally shorting two of the phases somehow, so that'll await further testing, but I didn't see any shorts on the wires and connectors before the motor and the wires on the motor phases are inherently shorted.

But, I kind of wonder if the motor might be partially defective.

 

[Grinhill]

My money's on a loose magnet. Is it one click per rev? I had plenty which stay basically in place, but either slide towards the stator or have one edge sitting higher than the other.

 

[liveforphysics]

Sounds like a mechanical problem rather than electrical.

 

[swbluto]

Yeah, quite possibly. I noticed the bullet plugs were able to rotate with the part that was silver-soldered to the wire, so I decided to cut down the complexity and just soldered the motor wires straight to some andersons. I also added solder to the andersons to try t secure it. So far, I haven't had problems, so I'm guessing the problems lied some-where with the connectors. It just seems funny I haven't been able to recreate the behavior since it doesn't seem like the possible connectivity problems are that myriad in their essence, but yet holding the motor wires in some position certainly did seem to recreate the behavior.

By the way, the wires leading out of motor that look like bare copper were insulated as I found soldering was impossible. I found that I was able to burn off the insulation using a flame, but even then the copper didn't seem easy to solder, however, I was able to get a little solder on with persistence.

 

[liveforphysics]

Yeah, quite possibly. I noticed the bullet plugs were able to rotate with the part that was silver-soldered to the wire, so I decided to cut down the complexity and just soldered the motor wires straight to some andersons. I also added solder to the andersons to try t secure it. So far, I haven't had problems, so I'm guessing the problems lied some-where with the connectors. It just seems funny I haven't been able to recreate the behavior since it doesn't seem like the possible connectivity problems are that myriad in their essence, but yet holding the motor wires in some position certainly did seem to recreate the behavior.

By the way, the wires leading out of motor that look like bare copper were insulated as I found soldering was impossible. I found that I was able to burn off the insulation using a flame, but even then the copper didn't seem easy to solder, however, I was able to get a little solder on with persistence.

The wires are enameled. If they weren't then your windings wouldn't be windings, they would be clumps of copper short. If you burn it off with flame, you end up with copper oxide salts which don't bond to solder covering your wire.

Set the area you wish to remove the enamel from onto a pill of asprin (yes the medicine, and no, you can't use Tylenol) . Touch a soldering iron down onto the wire and push it into the asprin until the asprin fumes a bit. Your enamel comes right off, and the wire stays shiny and clean. Takes about 3-5 seconds with a hot iron and an asprin pill to strip a bundle of enamled wires.

 

[johnrobholmes]

Andesons plugs can work loose after a while. I had problems similar to that because of them.

 

[fechter]

Set the area you wish to remove the enamel from onto a pill of asprin (yes the medicine, and no, you can't use Tylenol) . Touch a soldering iron down onto the wire and push it into the asprin until the asprin fumes a bit. Your enamel comes right off, and the wire stays shiny and clean. Takes about 3-5 seconds with a hot iron and an asprin pill to strip a bundle of enamled wires.

Dang! never heard of that trick before. I'll have to try it. How does it smell?

If the motor had a shorted phase wire, there would be mechanical resistance to turning the rotor. You can try turning the motor shaft and short combinations of phase wires to see how this feels. A single short usually gives a heavy cogging feel.

 

[recumpence]

Did you shorten the motor wires when you setup your system? If so, yes, you need to remove the enamel. That can cause the issues you are having.

I like luke's idea/suggestion. Very cool. It is tough scraping the enamel off each strand with a knife.............

Matt

 

[swbluto]

Yes, I shortened the motor wires when I was making the new connectors. Yes, I did notice the cuprite oxide from the flaming and tried to remove most of it with some acetone, and the solder did appear to adhere a little better though not as cleanly as normal copper. Anyways, I'm sure the soldering job is good enough for my purposes.


On another, the problem resurfaced. NOOOOO! So the only suspect left is the original anderson connector attached to the motor wires extending from the ESC. So, assuming they might be 'loose', how would I go about tightening them?

The most straight-forward solution seems to be replace it with soldered connectors to secure it, but I'm starting to run out of andersons and I'd prefer not to waste.

 

[johnrobholmes]

hard wire, new plugs, bullet plugs. I like Castle bullets.

 

[swbluto]

Ok, today I was having more than intermittent problems with my connectors. When I needed my scooter most, it was completely not working UNLESS the connector was pointing straight up. So I pulled the wire taut and bend down on my scooter like a man to make sure I didn't pull the wire out (It extends out of my backpack).

Thinking that I confirmed there was a definite problem with the connector this time, I looked at it and see what I found.





It looks the right red connector's tongue has caved in quite a bit or otherwise sprung down. Also, it seems that the connector itself has melted a little bit. I remember that I'm occasionally pulling 90+A phase current through this 45 amp connector and I think I've found my culprit - the connector sucks. Ok, that's a bit harsh, I'm just using the wrong rating.

So, I'm now looking to upgrade. I found the 75A version of the powerpole connector to be a little bit bigger than what I was hoping for (I don't exactly want it to scream "I'M ELECTRIC!!!"), so does anyone know of any small high-amp connectors that I can put into a configuration of three, and can be plugged in and out in one hand motion? Bullet plugs are great and all, but I would find it really annoying if I had to constantly plug in three separate plugs every time I wanted to plug into the scooter.

 

[swbluto]

Set the area you wish to remove the enamel from onto a pill of asprin (yes the medicine, and no, you can't use Tylenol) . Touch a soldering iron down onto the wire and push it into the asprin until the asprin fumes a bit. Your enamel comes right off, and the wire stays shiny and clean. Takes about 3-5 seconds with a hot iron and an asprin pill to strip a bundle of enamled wires.

Dang! never heard of that trick before. I'll have to try it. How does it smell?

I just tried it with some other wires and the fumes are undeniably toxic, but I didn't use 100% pure aspirin, I used excedrin which about 30% of it is aspirin - it also had acetaminophen and caffeine. They burn the mucilaginous membranes like no other (Mainly the nose). But, it was also undeniably successful in removing the enamel. My advice - work in a well ventilated area with some kind of mechanism to keep the smoke out of your face, especially your nose.

 

[swbluto]

I doubled up on the andersons so it looks like it should be good now. For one thing, it sure is a whole lot tougher to take the connector block apart!