ESC issue??

[federico1974]

Big issue (?!) with my 2 CARS (Kyosho RB5 and AE B44) on Sunday!. I’ve been talking with all my club mates and looked for in different forums: I found similar issues; bud did not really find an answer…
May be some of you can help….: I started training with the RB5; everything ok for 2-3 laps, then it started to suddenly stop and start again, 2-3 times, until it finally stopped. Took the car and had a look at it: No radio issue: (servo working perfectly), but the motor just did not work.

My tries:

1. Change the sensor cable: not working

2. Reconfigure the ESC: not working (when reconfiguring the ESC the motor does not “beeps” as it should do)

3. I look at the lights of ESC (Sphere competition) and everything seems to be ok, but the motor is still not working

4. Since I recently installed a lipo volt-cut I checked the wires and re-wired the ESC: not working

5. I thought it may be the low battery radio; charged it: not working

6. I thought it may be my Spektrum was dead. I asked a mate to bind his spectrum to my receiver: not working (servo still working ok)

7. I thought: just calm down, either there is a problem with the Lipo-cut, or the motor is dead. Better to use my B44 today and look after those issues at home

8. Plug the B44 and happens the same!!!! (No Lipo-cut installed)

9. Now: of course your ESC can die, but 2 on the same day, one after the other, and one of them did not even start???? (the one on the B44)??????



..on Monday at home…


10. I tried another motor (5.5) on the B44 and it worked (a bit hot, but worked)

11. Tried the same motor on the RB5: worked for 30 secs and then stopped

12. Tried the again the same motor on the B44: not working any more

Did REALLY my 2 ESC die at the same day and destroyed 3 motors??????


If it helps this was my equipment:
RB5
LRP Sphere competition, LRP 7.5 sintered, Spektrum (normal receiver), Novak lipo smart-stop, 6 cells ni-mh battery, KO 2123 (correctly wired to the ESC)

B44
Nosram Matrix Evolution (same as LRP sphere competition), LRP 6.5 bonded, Spektrum (micro receiver), 6 cells ni-mh battery, KO 2413 low profile

Thanks in advance to anyone can help

Federico

[Dagger Thrasher]

I don't think you've destroyed anything...certainly not your motors, anyway (pretty much the only way to fry a brushless motor, other than by factory defect, is to overheat it).

I might have read this wrong, but are you running a LiPo cut-off with NiMH? If you are, then that would certainly explain the starting and stopping, but wouldn't explain why the B44 won't run without a Lipo cut-off...

...which might point to the sensor cable between motor and ESC. This sounds a little like a bad soldering joint perhaps on the ESC's sensor plug, but to have bad joints on the plugs of *both* ESCs is unlikely. Bad solder joints on the motor power wires would more likely cause cogging than random failures, so I don't think it's that. Which, in turn, might point to a problem with an item that's common with both buggies.

This is a strange one, but maybe i'm missing something obvious; I'll have a think. What actual NiMH cells are you using?

[federico1974]

Hi Dagger Thrasher and thanks for answering.
You understood right: I had a lipo cut-off mounted and I ran Nimh. I’m not (too) stupid, it’s just that I had time to mount it last week and I’ll receive my brand new lipo (hopefully) in few days.
Just to avoid cut-off problems I got 100% sure battery were properly charged, so to me it sound strange even the behavior of the RB5…
During my tries I re-soldered (at least twice) each motor, and I cannot believe I soldered it bad every single time…. I tried 3 different sensor cables on both esc.
Regarding the batteries they are EP4600 08 spec (no selection) and I checked all the cells one by one: everything ok…

Originally Posted by Dagger Thrasher

This is a strange one, but maybe i'm missing something obvious; I'll have a think.

...please do have it: I have the first regional this year next sunday and won't have time to purchase new stuff...

[Fabs]

what's this lipo smart stop you have on the RB5 ? Did you start having problems after you installed it?

[DCM]

what Transmitter?

[Fabs]

ok had a look and i'm wondering why did you install this smart stop, seen as the LRP/NOSRAM speedos have a lipo cutoff mode already.

Are you certain there isn't a shortcut in your LRP speedo in the wires going to the motor ? ( it could be on the speedo side). Certainly a shortcut there will fry your motor and would explain why the 5.5 stopped working.

[federico1974]

Hi DCM, the transmitter is a 3VC with spectrum pro

[federico1974]

hi Fabs, before buying the lipo smart stop I tried the speedo in lipo/nimh automatic mode and simply it did not cut... (i tried it with 3 nimh cells and did not cut).

I'm quite sure I have no shortcut in the LRP speedo, and almost impossible to have the same thing in 2 speedos! (I did not touch the Nosram since about 3 weeks an it has always been working properly)

[Fabs]

it's designed for lipos not NiMH the fact that it didn't cut with NiMH doesn't mean it won't in Lipo. Usually it takes a good 4 minutes and a bit running 5-cell mod for it to cut if it's in Lipo mode, I don't think you'll ever cut off with 6 cells unless you proper dump the pack.

Shortcuts can happen anytime, maybe you have a bit of metal that got stuck on the ESC board and is shorting the wires. I've seen it before and usually it's the motor that melts not the speedo. Easy way to find out is to open your motors and have a look at the wiring.

[DCM]

right, when it stops, is there still lights on the receiver?

I would be looking at ditching the smart stop, as if you got a lipo cut-off on your ESC, they are pointless, and maybe triggering your esc to shut down.

Also, just check the light on the spektrum module, that the light is on. I have not had an issue with my 3VC and Spektrum module, but I know there is an issue with the KO modules.

[federico1974]

Yes, the light on the receiver is still on (and the sttering works perfectly) on both receivers. I explained reason why I have the lipo cut-off: the ESC simply does NOT cut off. By the way, before mounting it I wrote to Novak asking for a hint on the mode to use (ni-mh vs automatic lipo/nimh), and they told me it was the same.

[federico1974]

Originally Posted by Fabs

Shortcuts can happen anytime, maybe you have a bit of metal that got stuck on the ESC board and is shorting the wires. I've seen it before and usually it's the motor that melts not the speedo. Easy way to find out is to open your motors and have a look at the wiring.

and what should it look like if "melted"???

[Fabs]

Originally Posted by federico1974

and what should it look like if "melted"???

The varnish on the wires instead of being glossy would be burnt.

[federico1974]

ok, I'll check it tonight, thanks!

[COFFIN DODGER]

I would suspect the transmitter may be the guilty party (it's the common link between both cars). I had a similar problem with my Sanwa Super Exzes with Spektrum module . I cleaned and bent the pins that the module fits to slightly and never had a problem since.

[federico1974]

Hy Coffin Dodger and thanks.
Yesterday I did what you suggested. Well, I don't know if this was the real cause, but now one of my two esc is alive!!!!! (the b44 one). I checked the 3 motors and the 2 sensor wires and all of them work fine on the b44. (opened one of them and the varnish is glossy: thanks Fab)
Still the ESC on the RB5 does not work (even without the lipo-cut)
I also pulled out and cleaned all the connectors from the 2 spektrum receiver, leaving all the cables “free”, just taking care they do not touch the transmission on B44
I thought a series of factors might have caused the "diseases" of my babies:
1. the esc on the RB5 died (just by itself of for wiring issues)
2. the connection pins of my spektrum module did not make perfect contact
3. some of the cables of the esc on the b44 was not in perfect shape and leaving it “free” I got having a good contact.

Does this make sense?


If this makes sense this is the conclusion: the ESC on the RB5 is dead; the one on the b44 (hopefully) not: it was jus a series of coincidences and the motors (for sure) are OK.