shizack

I'm installing an HDX 4200 9T with an Eflite 25A Pro ESC (EFLA1025) in the King 2. I am running an external BEC and have removed the center red wire from the ESC micro connector. Sometimes it'll spin up and get jittery; other times it'll just jitter. It does this wired for either direction. I've changed every programmable option in the ESC to no effect. Tried four different fully charged batteries. I have yet to even mount the motor in the frame.

I did notice earlier that the model number of the ESC is EFLA1025 - does the "A" mean I got the airplane version and I'm just screwed? Since I've removed the red wire from the RX connector, I'm sure the LHS won't take it back.

Any assistance would be greatly appreciated.

FMB42

The Eflite 25A Pro ESC (EFLA1025) is indeed intended for fixed wing aircraft and heli ESCs often have a higher peak amp rating due to the current that they pull. However, the HDX 4200 BL motor is, IIRC, rated for 23.5 amps max and the EFLA ESC is rated for 30 amps max so this combo might just work.

I would first start with reconnecting the center red wire on the ESC followed with a test of the system with the external BEC removed. I would also go over the ESC programming once again while you're at it (make sure that you have the TX idle up switch turned to "normal"). I usually program the "throttle range" with the thrott trim tab centered. I'm not sure if the HDX 4200 is a 2 or 6 pole motor but you would normally use "low" timing for a 2 pole motor and "mid" timing for a 6 pole motor. Some 6 pole motors will not operate correctly with the timing set to "low", while using "mid" timing can cause excessive current draw on 2 pole motors.

Also check the following;

Make sure that the TX antenna is fully extended and finger tight and that the batteries are good.

Make sure that you are not picking up any external interference from lighting, etc.

Make sure that you don't have the TX too close to the RX.

Make sure that all the connections are clean and tight.

Double check the ESC voltage input and output.

If doing the above works out then try installing the ext. BEC again.

I'm sure that you have already tried the above but I thought that I'd mention them anyway. That said, there is also a chance that you have a "bad" motor, ESC, or external BEC.

Good luck and good flying!

P.S. I would be careful about running the motor under "no-load" conditions (i.e. not mounted and or not spinning the main blades) as this could possibly draw too much current and thus cause the ESC to shut the motor down.

shizack

Thanks for the tips, but I have tried everything you mentioned except checking the "output" voltage of the ESC. I have a decent multimeter. How is this done? Is there a certain voltage I'm looking for between the bare motor leads, or between the leads and ground? Or do I leave the motor connected and wedge the probes into the bullets?

Anyhow, Rusty is sending me a Dynam 30. This ESC is known to work well in the King with the 4200, so if the same thing happens, it's the motor.

Thanks again.

tbaus

Can you set and did you check the timing on your ESC? If so, what is your timing set to? ( As FMB42 alluded ...)

FMB42

Sorry, I was thinking (?) of a brushed system. I have never measured the output voltage on a brushless ESC and can't find any info on how to safely do this. I do know that you must use a multimeter with a 10 mega ohm impedance rating when working with electronics tho.

I should have mentioned that you might try re-routing the Rx antenna as it may be picking up interference from the new ESC/motor.


Found some general brushless motor/ESC troubleshooting tips that might be of some help;

Hyperion General Brushless Motor Wiring Instructions
http://www.allerc.com/motorwiring.htm


Manual of Thunder Power Sensor less Brushless Motor Speed ...
http://www.rctoys.com/pr/pr-html/thu...esc-manual.htm