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-   -   Serious problem with my pusher jet. (http://www.Wattflyer.com/forums/showthread.php?t=73398)

abborgogna 03-21-2014 04:15 AM

Serious problem with my pusher jet.
 
I just finished putting together a pusher version of the Su-27 and I have an ESC/Motor problem. With extension cables between the ESC and the battery the motor does not want to run. The receiver and servos all work fine, just the motor will not work. Without the extension cables everything works fine. l have had this problem on three different ESCs and with the extension cables between the motor and the ESC or the battery and the ESC. I have also swapped the motor and still have the problem. It seems I am dropping two much voltage between the ESC and what it is connected to. The extension is approximately 11.75 inches and I am using 12 gauge wire made for use electric model airplane applications.

Has anybody else had this problem.
Andy

pmullen503 03-21-2014 04:44 AM

Sounds like you have a bad extension. 12" of 12g wire will not drop the voltage enough to prevent the motor from running.

fhhuber 03-21-2014 04:51 AM

Bad connections and/or inadequate wire gauge. 12 Gauge should be good for most of the common e-power stuff, but may not be heavy enough for larger models.

We don't really have a lot of info to go on here...

It is better to extend between motor and ESC than between ESC and battery.

solentlife 03-21-2014 05:08 AM

I'd test eachj lead separately on a meter - see if continuity maintained ... not uncommon to have a broken lead inside insulation.... or bad connector one end.
I've even seen bullets soldered on that have insulation IN the solder ...

As another says - try and keep extensions between ESC and Motor ... not Battery to ESC.

Nigel

abborgogna 03-21-2014 06:24 AM

I used bullet connectors between the battery input wires on the ESC and the extension wires. I must be getting enough of a voltage drop under load across this connection to cause a problem. These are the same bullet connectors most ever motor uses. I will direct connect the wires together tomorrow and if that doesn't work I will run the extension from the battery connection all the way back to the ESC.

Larry3215 03-21-2014 06:32 AM

It could be a cold solder joint. Try re-heating ALL your soldered connections. Get the solder melted, then let it cool on its own without moving anything. Also, dont use anything to speed up the cooling. let it cool all by itself.

Even very small vibrations or movements of the wire as the solder cools can ruin a solder connection and make it have very hi resistance. It may look perfect and still be bad.

solentlife 03-21-2014 07:41 AM

Quote:

Originally Posted by abborgogna (Post 943183)
I used bullet connectors between the battery input wires on the ESC and the extension wires. I must be getting enough of a voltage drop under load across this connection to cause a problem. These are the same bullet connectors most ever motor uses. I will direct connect the wires together tomorrow and if that doesn't work I will run the extension from the battery connection all the way back to the ESC.

I NEVER use bullets on Battery to ESC - too afraid of one day making a mistake. I use Deans or XT60 to make sure I get polarity right. Bullets I reserve for Motor leads so I can swap over if necessary.

On a model where extension is permanent - then I solder the wire ends together with heat shrink over.

Nigel

CHELLIE 03-21-2014 07:48 AM

Quote:

Originally Posted by abborgogna (Post 943173)
I just finished putting together a pusher version of the Su-27 and I have an ESC/Motor problem. With extension cables between the ESC and the battery the motor does not want to run. The receiver and servos all work fine, just the motor will not work. Without the extension cables everything works fine. l have had this problem on three different ESCs and with the extension cables between the motor and the ESC or the battery and the ESC. I have also swapped the motor and still have the problem. It seems I am dropping two much voltage between the ESC and what it is connected to. The extension is approximately 11.75 inches and I am using 12 gauge wire made for use electric model airplane applications.

Has anybody else had this problem.
Andy

Hi Andy :) What size motor, Esc, lipo are you using ???? 12 gauge wire should work ok for up to a 60 size motor, bigger than that, you might want to use 10 gauge wire, I agree with others, that a bad solder joint or loose bullet connection might be a problem too, Take care, Chellie

JetPlaneFlyer 03-21-2014 01:47 PM

It's hard to figure how this could be anything but a bad solder joint, bad connection or (hard to imagine) a broken wire.

The normal voltage drop you get in wiring could not prevent the motor from running. Having said that it is very bad practice to significantly extent the wires between the battery and ESC because inductance in the extended wiring will lead to voltage spikes which over time is likely to kill the ESC... but it wouldn't prevent it running initially.

solentlife 03-21-2014 02:32 PM

Quote:

Originally Posted by JetPlaneFlyer (Post 943200)
It's hard to figure how this could be anything but a bad solder joint, bad connection or (hard to imagine) a broken wire.

The 'silicon' coated wire that many use - the insulation may be soft and pliable - but I've had it hide a break so well - it took literally stretching the wire to find it. Stiffer wire like I use for extensions can also be hard to find except when you go to form it to shape - then it becomes obvious.

One of the more common breaks is just inside insulation where the solder has flowed into the strands and you get a sudden stress point at end of the solder. The insulation can hold that strongly ... needs a really good pull to find it.

Nigel

crxmanpat 03-21-2014 04:45 PM

I'll throw in as well and say it sounds like either a bad solder connection, or a problem with the wire of the extension itself.

Also, I only use Deans for ESC to Lipo extensions, never bullets. I only use bullets on ESC to motor extensions.

abborgogna 03-21-2014 06:13 PM

OK guys I feel really stupid right now. First the good news it's fixed. I decided to swap in a different ESC and when I pulled one of the motor/ESC connection the motor side of the connector stayed with the ESC side of the connector. The wire had broken internally and was covered by the shrink tubing it wasn't until I pulled on it that break came apparent. What was really frustrating was I had tested the complete system prior to installation in the plane and everything was fine. It failed after installation, I must have tugged too hard on the ESC and broke the wire. Anyway all is well. Thanks for all the help.
Andy

crxmanpat 03-21-2014 07:34 PM

Andy,

Glad you got it sorted!

solentlife 03-22-2014 02:42 AM

Quote:

Originally Posted by abborgogna (Post 943211)
OK guys I feel really stupid right now. First the good news it's fixed. I decided to swap in a different ESC and when I pulled one of the motor/ESC connection the motor side of the connector stayed with the ESC side of the connector. The wire had broken internally and was covered by the shrink tubing it wasn't until I pulled on it that break came apparent. What was really frustrating was I had tested the complete system prior to installation in the plane and everything was fine. It failed after installation, I must have tugged too hard on the ESC and broke the wire. Anyway all is well. Thanks for all the help.
Andy

Broken wire ... get's 'em every time !

Great to hear you have it fixed.

Nigel


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