ORIGINAL: tony51
Today for the first time I tried out the power system on my A-10. It was an on-the-ground static test with the plane's movement blocked. The results are very disappointing.
The battery was freshly charged, and my DVM showed over 10 volts immediately before the test. The DVM is pretty accurate, by the way. I installed the battery and ran the engines for less than two minutes before they began to slow and then just stopped running. I took the battery back out and found that it was very hot and that it still had about 9.4 volts. During the test I had varied the throttle up and down a few times, and overall I that overall the average throttle setting would have been roughly 75% of max.
My questions are: why did the motors stop when the battery still had almost a full charge and why was it so much hotter than the ambient air? And could a bad ESC be the problem?
One other thing. At mid throttle the noise from the motor/fan units seemed much louder, and the vibration much more, than at either lower or higher throttle.
If anyone can suggest what's wrong or what I should try next, please tell me.
Do NOT static test EDF for extended periods of time you would likely damage your components due to overheating. It is different in real flight as you have much better airflow over motor, ESC, battery,...etc in real flight so the components can run longer without issue. Static test should only be a few seconds just long enough to get a stable reading.
If you are using the stock NiMH battery that battery is most likely overloaded so the voltage under load(when the motor is running) may drop below cut-off voltage quickly so the ESC cut off the power. It could also because the ESC is overloaded/overheated so it shut down for that reason.
The vibration you see means that the fan is NOT balanced and centered perfectly so that it will have certain resonance frequency which cause severe vibration at certain RPM. You need to balance and center the fan unit which is a rather tedious task and you need a balancer to do that.