Brushless Theory... I'm stumped.
#1
Brushless Theory... I'm stumped.
So I head out to practice with my 8ight E. The battery is fully charged from yesterday, and I've got a decent set of tires, I'm ready to go, or so I thought. The first few laps, things go just as they did at the last race, perfect. Then it starts to slow down, like I'm out of juice. I put the battery on charge, and it's over 15 volts. I check it on the balancer, and all the cells are equal. Hmm, maybe it's not the battery. I'd already checked the ESC and motor temps, well within spec(140 on the motor, 130 on the ESC) It's got a ton of off the line power, but as soon as it starts rolling, little or no power/speed, as if the battery is dead. I check again, voltage good. We put a voltage tester on the battery leads and hit the throttle, plenty of voltage. Hmm...
So I give up and take the car back to my shop. I try a few things, programming card, radio calibration, etc... nothing solves the problem. So I try to reset the ESC itself, and initially, it seems to be on the 5S profile(I'm running the Losi 4S 5K mah pack). Hmm, I never changed it, so I change it back. I get the same lame performance. As I'm messing with it, wheels spinning free, I shoot the temp gauge at the motor, it's HOT, like 150 ish... I keep messing with it, and suddenly, the motor is running reverse rotation! Now WTF?! So, knowing what I know about brushless, I swap the leads to the motor. Now it's going forward, but seems to have the same issue. Killer... explosive off the line, then poof, it's slower than a T-spec! According to the blinking lights on the ESC, I have everything right. Did I brake the motor? I'm hoping I've just got the programming all goofed up. I ran through the instructions, but it's not working. I plan to call Tech Support when they open in the morning.
What sux is I have a race this coming weekend. So if my motor or ESC suddenly took a dump, I'm out of the race. I was pretty frustrated with it, so maybe I just missed something. I couldn't get the ESC programming software to install on my PC, so I'll try another one. Maybe there's something going on that I inadvertently caused...
So I give up and take the car back to my shop. I try a few things, programming card, radio calibration, etc... nothing solves the problem. So I try to reset the ESC itself, and initially, it seems to be on the 5S profile(I'm running the Losi 4S 5K mah pack). Hmm, I never changed it, so I change it back. I get the same lame performance. As I'm messing with it, wheels spinning free, I shoot the temp gauge at the motor, it's HOT, like 150 ish... I keep messing with it, and suddenly, the motor is running reverse rotation! Now WTF?! So, knowing what I know about brushless, I swap the leads to the motor. Now it's going forward, but seems to have the same issue. Killer... explosive off the line, then poof, it's slower than a T-spec! According to the blinking lights on the ESC, I have everything right. Did I brake the motor? I'm hoping I've just got the programming all goofed up. I ran through the instructions, but it's not working. I plan to call Tech Support when they open in the morning.
What sux is I have a race this coming weekend. So if my motor or ESC suddenly took a dump, I'm out of the race. I was pretty frustrated with it, so maybe I just missed something. I couldn't get the ESC programming software to install on my PC, so I'll try another one. Maybe there's something going on that I inadvertently caused...
#2
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sound like 1 of the 3 motor leads has a bad connection.I had it happen once in my 1/10 truck.1 of the motor leads was unsoldered from a bullet connector I had in line so I could change motors without soldering at the track.It was fine off the line , but fell on it's face at the 1/3 throttle point. Worth investigating, I may be wrong.
#3
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how smooth is the motor at low RPM?
#4
Worth investigating, I may be wrong
how smooth is the motor at low RPM?
The fact that the motor gets so hot so suddenly, has me curious about the motor itself. I was well within operating temps up to this point, really not sure what's going on now. It could be as simple as having the wrong program... darn it! lol
#5
Be careful about running the motor unloaded for a long period of time. It is not good for the ESC.
I had one run unloaded for about 3 or 4 minutes while I was struggling to get it programmed. It just quit, so now I have to get it sent in. (It was an SS Novak.)
I had one run unloaded for about 3 or 4 minutes while I was struggling to get it programmed. It just quit, so now I have to get it sent in. (It was an SS Novak.)
#6
I talked to Tech Support this morning. It's getting boxed back up and sent to IL for warranty repair.
Before I gave up last night, I got it to do some pretty weird stuff. First, it started running backwards... I didn't reverse the motor leads, it just did it on its own. I swapped them, to see if there was something wrong with the motor, and it will run forward, but the motor got pretty hot. So I swapped the leads back. Now when you turn it on, it'll run for about 1 second. Then, it just cogs. I've checked and rechecked my battery, and I'm pretty sure that's not it. So, it's headed off to service, and I'm trying to figure out what to race this weekend.
Before I gave up last night, I got it to do some pretty weird stuff. First, it started running backwards... I didn't reverse the motor leads, it just did it on its own. I swapped them, to see if there was something wrong with the motor, and it will run forward, but the motor got pretty hot. So I swapped the leads back. Now when you turn it on, it'll run for about 1 second. Then, it just cogs. I've checked and rechecked my battery, and I'm pretty sure that's not it. So, it's headed off to service, and I'm trying to figure out what to race this weekend.
#7
I talked to Tech Support this morning. It's getting boxed back up and sent to IL for warranty repair.
Before I gave up last night, I got it to do some pretty weird stuff. First, it started running backwards... I didn't reverse the motor leads, it just did it on its own. I swapped them, to see if there was something wrong with the motor, and it will run forward, but the motor got pretty hot. So I swapped the leads back. Now when you turn it on, it'll run for about 1 second. Then, it just cogs. I've checked and rechecked my battery, and I'm pretty sure that's not it. So, it's headed off to service, and I'm trying to figure out what to race this weekend.
Before I gave up last night, I got it to do some pretty weird stuff. First, it started running backwards... I didn't reverse the motor leads, it just did it on its own. I swapped them, to see if there was something wrong with the motor, and it will run forward, but the motor got pretty hot. So I swapped the leads back. Now when you turn it on, it'll run for about 1 second. Then, it just cogs. I've checked and rechecked my battery, and I'm pretty sure that's not it. So, it's headed off to service, and I'm trying to figure out what to race this weekend.
#8
I didn't check that, the motor has never been off the car before. I did slide it out pretty far to get the new pinon on, but beyond that, the mount has never been removed, and this happened mid run. It basically slowed more and more, as if the battery died. I'm thinking it either shorted internally, or the programming is all screwy. I give up for now, Losi Tech Dept gets to take a shot at it.
#10
Well, I started to hook up my Novak 4.5, just to see if it would spin. But I feared the issue was with the ESC, and the last thing I want to do is break that motor too! I shipped it off today; should arrive at Horizon's Losi Tech Dept. by Thursday. If all goes well, I might have it back in a couple weeks. If not, I have to go buy some nitro fuel!
#11
i did something pretty 'tarded on a sensorless system once.... i thought id make it look "neater"by braiding the three motor wires together,as they were pretty long.when you do that it really seems to confuse the esc.
anyways,thats too bad hope you get it fixed!
anyways,thats too bad hope you get it fixed!
#12
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In reality, you did confuse the ESC. Even sensorless ESCs are sensored. Instead of using a separate sensor array and cable, the sensorless ESC picks up feedback voltage generated on the windings by the magnets of the rotor passing by them. Look up Faraday's Law on the internet for an explanation of this. By braiding the wire, you actually caused phase cancellation of this feedback voltage. Preventing the ESC from properly detecting the rotor position.
#13
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I talked to Tech Support this morning. It's getting boxed back up and sent to IL for warranty repair.
Before I gave up last night, I got it to do some pretty weird stuff. First, it started running backwards... I didn't reverse the motor leads, it just did it on its own. I swapped them, to see if there was something wrong with the motor, and it will run forward, but the motor got pretty hot. So I swapped the leads back. Now when you turn it on, it'll run for about 1 second. Then, it just cogs. I've checked and rechecked my battery, and I'm pretty sure that's not it. So, it's headed off to service, and I'm trying to figure out what to race this weekend.
Before I gave up last night, I got it to do some pretty weird stuff. First, it started running backwards... I didn't reverse the motor leads, it just did it on its own. I swapped them, to see if there was something wrong with the motor, and it will run forward, but the motor got pretty hot. So I swapped the leads back. Now when you turn it on, it'll run for about 1 second. Then, it just cogs. I've checked and rechecked my battery, and I'm pretty sure that's not it. So, it's headed off to service, and I'm trying to figure out what to race this weekend.
#15
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The damage may not always be visible to the eye. Good luck with everything.