bedbod

G'day all,

I have recently built up a Sakura D3 Kit, after being inspired by all of the neat drift cars on the forums. It's my first car since my old Super Hornet of old days, other than the crappy HSP brushless buggy I scored from the markets here in Dubai.

The build went well, except when I got to wiring up the motor. Its a Speedpassion Reventon Pro, with 10.5t sensored Yeah Racing motor fitted with a 15t pinion. I am running a GT-3B TX/RX combo. I had to dodgy extend the sensor cable with some neat soldering and extended wiring, due to the distance between the esc and motor. I have ordered longer cables to fix that up.

The issue I am having is the the motor seems to be randomly cogging, especially from a standstill, even worse after reverse. If I keep throttle on, it runs like a dream, but when i back right off (during transitions), the motor often makes a cogging/grinding noise until I back off. Reverse sounds pretty average too. The belts are definitely not slipping, and it runs beautiful when not cogging. The motor gets a bit hot after the cogging happens, and the more it happens. The TX also has to be set in to the reverse mode for the motor to run forwards.

I have attached a video below. Reverse is at around 0.04 (which I have fixed, due to having ABS set on my TX, and the cogging you will see is at 0.07, 0.18 and 0.25.

youtube.com/watch?v=Nu80L70_nsc Sorry, not enough posts to embed...

Here is what I have done/discovered in the lest few days:

- desoldered then resoldered all of the sensor wires until new ones come (I am currently deployed to the Middle East, so getting parts from home is a slow process)

- insulation tested the sensor wires for leakage current. No problems found.

- replaced the wires between the esc and motor with slightly longer ones, to reach the motor better. Problem still occurs.

- found that issue happens more reguarily after running for 5+ minutes. Straight from cold, it is around 1 in 5 jabs at the throttle. the more/longer i hold the throttle on, the hotter the motor gets. The issue happens the same in reverse

- pulled the sensorless motor from my hsp buggy, and put that in to try to eliminate the motor/sensor cable. Went fine for a few minutes, then started doing the same thing. I guess that brings it down to the esc or maybe a setting gone wrong.

- the esc flashes the red light (flat battery) constantly as soon as it is turned on, even with a fully charged on (tried a few batteries). Drives at full pace though.



Can anyone think of any setting on the esc or transmitter that may cause this to happen? I will be looking at ordering some new parts as soon as I can confirm the problem, but its just a shame that this would happen with all brand new parts.

ChickenRC

what battery are you using?

Nexus

iTrader: (42)

If you have one/any replace the sensor wire or sensor board. That might be the issue.

Justin33

iTrader: (45)

Its gotta be your sensor wire no matter how careful you are to lengthen it or repair it sensor wires are not something to mess with i've had the tiniest of nicks in the wiring not even a break in the wire and it caused problems i've even just had sensor wires that gave up no physical damage anywhere. Most consider them as disposable have a few extras around and always start there when trying to figure out a problem with cogging.

And sensorless esc/motors sucks they will always cogg at some point especially with weaker batteries.

Just wait till your new sensor cable comes and all ur problems will be solved u til then dont run it while its cogging you can cause damage with heat and stuff

bedbod

Cheers for the replies.

I am using a few brand new Gens Ace 5450 2S1P 45C batteries.

The red light on the ESC flashes when turned on, even with a fully charged battery. In the book, it says that means low battery. And I had a spin tonight for about an hour with the battery going the distance, just being careful not to really come off throttle fully.

I was dead set that it was the sensored motor, but when I put a sensorless motor in it did the same thing. Wouldn't that count the sensor cable out? Like the cogging is not really cogging, just violent shaking and buzzing, while slowly rolling forward.


I will be grabbing a new cable when I head back to Australia in 3 weeks, but I just want to drive it now! Dubai hobby shops havnt got a clue....

Qatmix

It will be woth trying to switch the low voltage cut-off to 3.0v (or lower to test) the reventon pro is a little sensitive when a battery dips on load and runs in sensorless mode (hence the occasional cogging) guys here race with it set to off