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Intermittent Motor Desync and Premature Thermal Shutdown on Dual ESC Configuration

Hi all,

I’m experiencing a puzzling issue with a twin-motor setup and would really appreciate some insight from HobbyKing support or anyone who’s dealt with similar behavior.

System configuration:

  • Motors: 2× Turnigy SK3 5055-430KV (same production batch)

  • ESCs: 2× HobbyKing Platinum Pro 100A (updated to latest firmware via LCD card)

  • Battery: Single 6S 5000mAh 45C LiPo, split to both ESCs

  • Props: APC 15×8E, balanced and matched

  • Platform: Twin-engine fixed-wing aircraft

  • Cooling: Good airflow; ESC temps monitored via telemetry

Issue encountered:
After roughly 3–5 minutes of sustained flight at around 65% throttle, one side consistently shows problems:

  • Brief motor desynchronization (audible RPM dip),

  • Followed either by recovery or an ESC thermal shutdown,

  • The opposite motor/ESC continues operating normally.

Additional notes:

  • ESC temperature at shutdown reads about 73–75°C, which seems low for a thermal cutoff.

  • Voltage sag is even across the system and well within acceptable limits.

  • Swapping motors and ESCs between sides does not move the issue — it always occurs on the same side of the airframe.

  • Signal leads are the same length and kept clear of power wiring.

  • Internal BECs disabled; running a separate external BEC.

Troubleshooting already attempted:

  • Tested different motor timing settings (low / medium / high)

  • Changed PWM frequency

  • Recalibrated throttle endpoints multiple times

  • Replaced signal wires

  • Added extra input capacitors close to the ESC

At this point I’m wondering if this could be related to airframe-specific EMI, grounding asymmetry, or some edge-case interaction between ESC firmware and back-EMF under partial load.

Has anyone seen something similar, or does HobbyKing have recommendations for diagnosing this further?

Thanks in advance for any insight.

 

 

polytrack

Richard Rivera

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You're facing an intermittent issue with your twin-motor setup that leads to motor desynchronization and premature thermal shutdown of one ESC fnaf. Let's break down the problem and explore potential causes and solutions. The airframe may have specific electromagnetic interference affecting the ESC's performance. Asymmetrical grounding could lead to signal integrity problems. There might be an edge-case interaction between the ESC firmware and back-EMF under partial load conditions.

This issue can be quite complex, involving various factors from hardware to software interactions. Keeping detailed records of your troubleshooting steps and findings will help in diagnosing the problem effectively. 

andre kyler 0 votes
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Interesting case. Since the issue stays on the same side of the airframe even after swapping motors and ESCs, it strongly points to airframe-specific EMI, grounding differences, or localized airflow causing partial ESC overheating or signal noise rather than a component fault. I’ve seen similar behavior where carbon structures or nearby wiring induced interference under sustained mid-throttle loads. From an enterprise troubleshooting perspective—similar to how we approach complex system diagnostics at i3solutions, where we design and support Microsoft-based, mission-critical environments—the key is isolating environmental variables, not just hardware. In large-scale automation projects, we often advise teams to hire senior Power Automate developers for complex enterprise workflows because subtle architecture-level issues don’t show up in basic testing, much like this ESC behavior.

Gohar Clients 0 votes
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You're dealing with a frustrating intermittent issue with that twin-motor setup, and I totally get why it's driving you nuts. Let me try to break this down in a way that makes sense.

Looking at your detailed troubleshooting, the fact that the problem stays on the same side of the airframe even after swapping components is super telling. This almost always points to something airframe-specific rather than a bad motor or ESC. Your temps at 73-75°C before shutdown are actually quite low for thermal cutoff – most ESCs these days are rated to handle 100-110°C before protesting, so something else might be triggering that shutdown behavior.

The desynchronization you're hearing makes me wonder about the signal integrity on that side. Even though you've replaced signal wires and kept them away from power lines, there could be something funky with how that particular ESC is interpreting the PWM signal. Have you checked if there's any vibration or resonance happening on that side of the airframe at that 65% throttle range? Sometimes physical vibrations can mess with sensor readings or cause intermittent connection issues.

Also, I know this might sound random, but I've seen similar behavior when people have grounding inconsistencies between ESCs. Even though you're running a separate BEC (smart move, by the way), the ground reference between the two ESCs might be slightly different, causing one to misinterpret the signal. Adding a thick ground wire between the two ESCs near the battery connection sometimes helps.

On a completely different note, if you're into video editing for your flight recordings, I've been playing around with alight motion 5.2 0 mod apk lately for stabilizing and coloring my FPV footage – it actually handles 4K footage pretty well and has some decent stabilization tools that might help you analyze those desync moments frame by frame.

Back to your twin setup though – one other thing worth trying would be to temporarily swap which side of the airframe gets which ESC signal from your receiver. If the problem moves with the signal, you might be looking at a receiver output issue or something in your wiring harness on that specific channel. If it stays put, you're definitely dealing with an airframe-specific gremlin.

Keep us posted on what you find – these twin motor mysteries are always interesting to solve!

Fakhar Zaman 0 votes
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Based on your description, the issue likely isn’t the motors or ESC hardware but something related to the airframe layout or localized airflow. Since the problem always occurs on the same side even after swapping components, it suggests that one ESC may be experiencing slightly poorer cooling or localized EMI from wiring, servos, or structural components. Even though telemetry shows 72–75°C, internal FET temperatures can spike higher and trigger protective behavior, leading to desync or temporary cutoff under partial load. Try repositioning the ESC, twisting motor leads, adding a ferrite ring on the signal wire, or testing the system outside the airframe to isolate interference. Sometimes these intermittent behaviors are as puzzling as random chatter you might hear on a Volusia County Police Scanner while playing a quick round of solitaire bliss—unexpected but traceable once the source is isolated.

 
 
Granvilteson Doylle 0 votes
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This seems like a tricky technical issue where one small factor is causing repeated failure, much like a difficult clue in a puzzle. Just as you methodically test components to find the root cause, using the right approach or tools helps you reach the correct løsning krydsord and solve the problem step by step.

 
 
stokes 0 votes
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