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sloper
11-18-2005, 03:39 PM
Hello, It's my first time here. I have a wiring question. I'm building a large pusher jet. I had intended to put the ESC in the battery hatch for ease of access but I read somewhere that you should not extend the wires between the motor and ESC. Since it is about 30" from motor to hatch should I put the ESC by the motor and extend the battery wires? Which wires are more likely to cause glitches? Thanks for your input.

qban_flyer
11-18-2005, 04:25 PM
Hello, It's my first time here. I have a wiring question. I'm building a large pusher jet. I had intended to put the ESC in the battery hatch for ease of access but I read somewhere that you should not extend the wires between the motor and ESC. Since it is about 30" from motor to hatch should I put the ESC by the motor and extend the battery wires? Which wires are more likely to cause glitches? Thanks for your input.

IMHO, I always have the ESC no more than 12" from the motor, preferably 6" and as far away from the RX as the ESC's throttle cable will allow me to. :)

sloper
11-18-2005, 08:35 PM
Well that would mean a 30" extension on the ESC Rx lead which would be next to the battery wires. What is the reasoning behind the short ESC to motor wiring?

hoppy
11-18-2005, 08:38 PM
From an ESC manufacturer - http://www.rcgroups.com/forums/showthread.php?t=262485&highlight=extend+

slipstick
11-18-2005, 09:09 PM
If the motor is brushed you can do whichever is easier. If it's brushless then extending the battery to ESC wires can cause real problems.

Steve

3dfoamworks
11-18-2005, 09:31 PM
I'd maybe add a Ferrite Interference Choke.

sloper
11-18-2005, 10:04 PM
I'll be running a Mega 22/30/3 with a Jeti advance 70 opto on 14 GP 3300 cells. I hope to pull between 50 and 60 amps.

trogdor
11-18-2005, 10:31 PM
If the motor is brushed you can do whichever is easier. If it's brushless then extending the battery to ESC wires can cause real problems.

Steve

I asked this of Shawn at CC on RCG on the referenced thread. I see esc to motor because of the sensorless design but why battery to esc?? Shawn said something about input capacitor but, technically, how can long battery wires matter??

qban_flyer
11-19-2005, 02:41 AM
From an ESC manufacturer - http://www.rcgroups.com/forums/showthread.php?t=262485&highlight=extend+

Thanks for that link Hoppy.

It saved me from what would have been a very convoluted explanatory diatribe.

To quote Shawn Palmer one of Castle Creations' gurus:

Adding to the motor side reduces accurate motor operation, and can be to the point of non-operation.

Adding to the battery side increases the strain on the input capacitor, and can lead to the loss of the controller.

Dr Kiwi
11-19-2005, 02:26 PM
Dave Thomas, in "Quiet Flyer", warned against extending battery to ESC leads - apparently this can lead to induced voltage spikes of as much as 40v on high powered systems.

As I recall, he said: "add 3ft - risk instant smoke".

For brushed systems all one loses by extending ESC to motor wires is a bit of current due to increased resistance - but for brushless, one is between a rock and a hard place, since extending the ESC to motor wires has its drawbacks too!

Cheers, Phil

sloper
11-25-2005, 10:23 PM
Well the info here was less than conclusive so I contacted Jeti. Here is their reply; Dear sir,It is absolutely necessary to extend wires between power accus and controller. Please use additional capacitors between plus and minus wire. Use high frequency capacitors - it is possible to send you money free.Best regards. J.Tinka If anyone knows what the power accus is that would be helpful.Thanks