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Old 03-19-2002, 09:25 PM   #1
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Default Schottky Diode Placement Question

I am going to re-run the wires in my car and I was wondering if I can put this Diode On the Motor or On the neg and Positive Wire before the Motor or since I have a LRP Quantum Competition Speed Controller can I solder it below the posts where the wires come out? I have 6 Stock Motors that I want to just pop in and out and it is a pain to take this Diode off the motor every time I want to put in a different motor. I know I can just go out and buy more Diodes but I was wondering if there was a simpler way.

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Mike Webb
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Old 03-19-2002, 10:08 PM   #2
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The closer you mount the diode to the motor the more effective it is. The best resource for this is the SCHOTTKY FAQ from Novak's site. Here's a quote and the URL...

...
For the highest efficiency, during the off-time while the motor continues to flow current, the voltage should ideally be as close to zero as possible. One reason Novak uses an external Schottky diode is because the closer the diode is to the motor, the lower the voltage drop during this period. This is due to the voltage drop through the wires back to the speed control. This will also reduce some radio noise due to the current spike not having to travel a long distance.
....

http://www.teamnovak.com/Tech_info/m...o/SCHOTTKY.HTM

Personally I just have a diode attached to each of my motors. It's just easier for me when I'm switching out motors between cars.
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Old 03-19-2002, 10:11 PM   #3
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Thanks Mushu.. Looks like I am going to be buying some Diodes next trip to the Hobby Shop .

Mike Webb
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Old 03-20-2002, 04:39 AM   #4
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Schottky diodes from hobby stores tend to be very expensive, just go down to your local electronics store (Radio Shack etc) with a schottky and you will find prices are much more reasonable. In Hong Kong RC stores are 5 times the prices of electronics store for Schottkys!!
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Old 03-20-2002, 06:27 AM   #5
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Do I want a Signal Diode or doing I want a Barrier Diode?

Those are the ones that I can choose from... and then what AMP and Volt and so forth .

Thanks

Mike Webb
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Old 03-20-2002, 06:27 AM   #6
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The novak diode's sell for about $5.
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Old 03-20-2002, 06:30 AM   #7
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Novaks are 2 for 5$

I need 10 so that is $25

From RadioShack I can get 10 for $4.90



that $20 savings can go towards motor brushes .

Mike Webb
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Old 03-20-2002, 08:02 AM   #8
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Just take one of Novak diodes with you. Thats what I did, they should be able to find you exactly the same thing for the numbers on the diode...sorry, I can't remember the exact spec!
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Old 03-20-2002, 06:26 PM   #9
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Default diode specs

45 volts, 9 amps, 0.4 forward voltage drop. i never could find them at the shack (radio shack)... ordered two from ae.

http://www2.towerhobbies.com/cgi-bin...1&I=LX2682&P=7

the photo is wrong, specs are listed at bottom of page
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Old 03-22-2002, 09:36 AM   #10
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Default Diode

I have seen a popular driver using 3 Schottky diodes mounted to his motor all at the same time. What does this do? He was running fast though.
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Old 03-22-2002, 09:32 PM   #11
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Default 3 diodes

the diodes should make the ESC run cooler and more efficiently. why someone would run 3 i do not know, 1 should do it. are you sure it's not capacitors you seeing, it's very common to run 3 caps & 1 diode on the motor
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Old 03-23-2002, 05:39 AM   #12
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Hyperformance

Im sure it was a Schottky. I was wonderin if it also improves he's braking once he gets off with the throttle. So what does the 16V caps and the soldered motor caps have in common? They have opposite sizes.
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Old 03-25-2002, 07:33 PM   #13
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I have seen many people running 2 diodes, but not three. I think that it is more eff.
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Old 03-25-2002, 08:13 PM   #14
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Guys,

Please read the link I posted below. You would run more diodes if you are running a hotter motor. From the Novak diode FAQ...

....
The hotter the motor that is used (i.e. the lower the number of turns), the higher the current that flows through the Schottky diode. In some cases, two diodes connected parallel must be used (connect both striped ends to motor positive and both non-striped ends to motor negative).
...

http://www.teamnovak.com/Tech_info/...fo/SCHOTTKY.HTM

I've seen plenty of images of cars running mod motors with multiple diodes attached in series. I really don't think more than 2 would be needed.
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Old 03-26-2002, 10:48 AM   #15
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mike-Webb,
I once asked Novak about placement, and they said as long as the Schottky is installed within two inches of the motor there should be no problems. And over a year later there haven't been.
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