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drcarlos

Stuttering Brushless

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Starting to tear my hair out with this.

A new 45a Hobbyking X-car esc turned up up along with a 12T Turnigy Trackstar motor.

Plugged in and set up with new 3.5mm bullets for the motor and Deans connectors on the battery, fully charged 5000mah 20c lipo and a charged 3000mah Nimh.

Sometimes runs OK, sometimes just stutters, connect the ESC to my 9T Trackstar and it spins up fine everytime can't get it to stutter, connect the 12T to my Hobbyking 100amp ESC and that runs fine, again it won't stutter.

I noticed that when stuttering the connectors on the motor wires get quite hot.

I read in another thread that someone else saw similar symptoms but his motor cogged and he had lengthened his wires to reach and had 2 sets of bullets.

I tried altering the timing to the lowest setting and also lowering the initial acceleration but that hasn't changed anything.

The other symptom is that when it stutters the fan stops spinning.

It seems to me that there maybe an intermittent short occuring, but I am not sure if it's motor or ESC and that fact I can't replicate the fault on my other motor or ESC puzzles me big time.

Anyone got any ideas?

Got some time to get this corrected (and any faulty parts swapped) as the car needs a new servo anyway so if we go bashing at the weekend he can take his Nitro.

Carl.

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I am somewhat concerned with the motor wires getting hot... Heat is usually the result of excess current draw OR a high resistance joint..

Is it the wire that's getting hot, or could it be the 3.5mm bullet connectors getting hot, and the heat radiating into the wires like a heatsink??

Personally what I would do is give the 12T motor a run with the 100A ESC, and the 9T with the 45A ESC and see if the problem reoccurs with either setup.. Just keep an eye on the temperature of the wires and connectors throughout the run..

ALSO check the temperature of the 45A ESC when running the 9T motor, as the 9T motor will be close to the limits of the 45A ESC, especially running in offroad conditions..

I only have two sensorless brushless systems, both HobbyWing, one 13T in my Mini, and a 9T in my 1/12 scale.. I did not notice cogging in the Mini, however the Cyclone 1/12 would cog quite bad at very low throttle settings, and he cogging made the 1/12 appear like it was stuttering..

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I had very similar issues, took me a while to track it down but it was the diff spinning up which was making the motor overheat and protection cutting in. I took the diff apart and visually it looked perfect. I put some heavy duty hpi thick grease in there, put it back together and it cured it. This on a WT01 chassis.

Cheers

Nito

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It is that 12t linked above and it will stutter when just connected to the motor, not even in the car. The heat is centred around the bullet connectors as well not in the wires. Both batteries make the 100a combo spin up fine.

I had some issues previously with the acoms radio set I am using here but the connected light in the RX stays on all the time, rather than flashing when I hit the accelerator and stopping turning and reconnecting like it did last time.

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Convinced this is the motor now.

There are marks to the casing and I can see that the box has been resealed as there is a second sealing tape over the first one, sneaky.

Going to RMA it as a faulty item that has clearly been used, returned probably faulty and they couldn't replicate it as it's intermittent and sent out again.

Taken pictures of the marks and resealing and a video of the fault.

Nitro this weekend it is then (if the weather isn't too bad).

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Sounds like you have lost a phase.. Check the resistance across the 3 wires.. If you lose a wire they stutter and get hot.

Saying that you say it works on the other esc... You may have lost a phase on the esc..

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No knowing brushless I wasn't sure what tha actual fault was, so when the speed control ran the 9T Trackstar perfectly I plumped for a faulty motor. The RMA was successful and last Friday we got the replacement 12T motor. We ran a pack through it last Saturday, finally setting up this car on the local disused runways and my boy is happy with it the speed seems well matched to the car and we got it nicely dialled on a high grip surface.

Full credit for Hobbyking here and their returns service as it was quick, free and hassle free too.

My 13.5T Trackstar sensored motor also arrived and I set up the Tamiya TBLE02 in Brushless mode which was fun.

I'm overall really pleased with these Trackstar motors and have a Superstock 12T Trackstar and 45A ESC Combo coming for my youngest lad.

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