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Problem: No power to motors

#1
Hi guys,

I have just finished building my ft cruiser and having installed all the electronics, I have no power to my motors. When power reaches the two ESC there are no bleeps evan though power is making it to the receivers and servos as I have complete control over them with my Spektrum DX5e. Heres the info;

Controller; Specktrum DX5e
ESC; 2x Turnigy Plush 25a (from hobby king)
Motor; NTM prop drive 28-30 750kv
Battery; Turnigy 2.2 3S

The ESC are hooked up to y-harnesses for the power and signal wires. I have not pulled out the red wire in one as Josh B didn't do it in the build video.

Here are some photos;(linked to dropbox)

https://www.dropbox.com/s/e3wdrjlfal0jcvo/IMG_3357.JPG - Motor setup
https://www.dropbox.com/s/q41qty09ssp4zq5/IMG_3356.JPG - One of the ESC (they are both the same)
https://www.dropbox.com/s/9xcu0vk8so7tvdj/IMG_3355.JPG - Whole plane with working servos
https://www.dropbox.com/s/wi32sbf342um4za/IMG_3354.JPG - Receiver
https://www.dropbox.com/s/0h3tju0kgi29igb/IMG_3350.JPG - Current set-up

I've tried just using one attached to the receiver and still nothing.

Thanks in advance, Will
 

CrashRecovery

I'm a care bear...Really?
Mentor
#2
If I remember correct josh did a how to for getting the motors to work. I'd look that up and see what you did wrong. It's under the wiring how to
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#5
No beeps from the motor, but power to the rx makes me wonder if you've got connection to the motors -- I take it you soldered the bullet connectors to the ESC? (IIRC, the bullets are pre-installed on the NTMs)

I'd check these connections -- the ESC uses one of the motor phases as a speaker, and if it's not beeping at bootup but the UBEC has power, either it's not booting up (possible but not likely on two ESCs in a row), or there's a broken connection to the motor.

Just looked at the pics . . . is that hot glue on the connections? I'm wondering if any got in the connector and is insulating the contacts.

It's a good idea to remove the middle pin on one of the two the ESC's control leads -- the UBECs will likely fight each other and at best burn extra power -- at worst, one of them could burn out. This, however, may not happen right away, and won't prevent the motors from beeping.
 

TomCub

Junior Member
#8
No beeps from the motor, but power to the rx makes me wonder if you've got connection to the motors -- I take it you soldered the bullet connectors to the ESC? (IIRC, the bullets are pre-installed on the NTMs)

I'd check these connections -- the ESC uses one of the motor phases as a speaker, and if it's not beeping at bootup but the UBEC has power, either it's not booting up (possible but not likely on two ESCs in a row), or there's a broken connection to the motor.

Just looked at the pics . . . is that hot glue on the connections? I'm wondering if any got in the connector and is insulating the contacts.

It's a good idea to remove the middle pin on one of the two the ESC's control leads -- the UBECs will likely fight each other and at best burn extra power -- at worst, one of them could burn out. This, however, may not happen right away, and won't prevent the motors from beeping.
I think this is a great idea; not sure but if the UBEC's are fighting or possibly increasing the voltage, this would be a really bad thing...life expierence; some receivers will stand up to 9 volts, most servos won't. Just changed all the servos in my 40!!
 

CrashRecovery

I'm a care bear...Really?
Mentor
#9
When you power up the plane have you throttle all the way up. Wait for a few beeps then bring it down. Should beep again. Unplug the battery and plug it in like your gonna fly
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#10
I think this is a great idea; not sure but if the UBEC's are fighting or possibly increasing the voltage, this would be a really bad thing...life expierence; some receivers will stand up to 9 volts, most servos won't. Just changed all the servos in my 40!!
The voltages won't add, but each UBEC will try to push the voltage to what they think is 5v. One will win, one will loose. If they're both close to the same "this is 5v" level, it'll just wear on them, if they're not close, one will pump charge into the other and one or both can burn out.
 

Jaxx

Posted a thousand or more times
#13
Does anyone know if this Tx has any built-in throttle safety features that must be disengaged before the motor/s will spin-up?

If possible, I would try disconnecting one ESC/motor combination completely to see if a single ESC configuration would work. Test each ESC/motor combination individually. If one works, then it has something to do with the dual motor configuration. If neither single setup works, then it could be an issue with the Tx or Rx.

This might sound like a dumb question, but is the battery fully charged?

This is a question for the experienced guys:

If the cell voltages are lower than the cut-off threshold programmed in the ESC, will it prevent the motors from spinning up? I know it will cut power to the motors during flight, but not sure how it affects initial motor start-up.
 
Last edited:
#14
Ok, it turned out to be a dodgy connection on the bullet connector so after reconnecting that I tested and it worked! Took it out for the first flight and had a few minor crashes. Mostly damage to the wheels so will buy some rubber wheels instead of the foam ones. I might make some wheel pants to go with them! Thanks for all the help. Will
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#15
Glad we could help you trouble shoot and get you in the air (even if it did put her back on the repair bench).

Post up some video or pics in the air if you can, and get that girl a nice coat of paint ;)

BTW, welcome to the forum, Will -- Here's to more flights between crashes!