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Author Topic: Graupner 500 7.2v motor  (Read 2030 times)

Ben Tickle

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Graupner 500 7.2v motor
« on: February 16, 2011, 04:19:05 PM »

Hi

I have a graupner 500 motor (7.2V) with a 20 amp esc. I was just wondering if i fit a lipo protector, could i have this motor running on 11.1 lipo pack?

Thanks

Ben :-))
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DickyD

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Re: Graupner 500 7.2v motor
« Reply #1 on: February 16, 2011, 05:01:08 PM »

Graupner 500 7.2V Nominal voltage 7.2V, Operating voltage range 3.6-8.4V .

Not good to over do it motor wont last long.

The Graupner 500E is the only one that has Nominal voltage 12V, Operating voltage range 6-12V in the 500 series.
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John W E

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Re: Graupner 500 7.2v motor
« Reply #2 on: February 16, 2011, 07:20:04 PM »

hi there

Dicky  :-))  The graupner 500 speed 500e that is motor - which you have mentioned operational voltage is between 12 & 18 volts.  This includes the gearbox on direct drive operating voltage is between 6 and 12 volts.      No load speed is 12,000 rpm  minimum.    This is the same motor which is fitted in the trawler I am busy with at the current time.  
The motor is driving a direct drive 3 blade prop of 55mm diameter and its only drawing 2.5 amps to 3.0 amps on a 7.2 battery.   The rpm is low mind, no good for a speed boat.



http://www.modelboatmayhem.co.uk/forum/index.php?topic=28028.0

aye

john
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DickyD

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Re: Graupner 500 7.2v motor
« Reply #3 on: February 17, 2011, 07:43:22 AM »

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nick_75au

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Re: Graupner 500 7.2v motor
« Reply #4 on: February 20, 2011, 10:57:47 AM »

Hi Ben,

Short answer yes ok2

Here is the maths

OK the standard motor (not race) 7.2 has a Kv of 2430 approx, so at 11.1  it will spin at 27000 RPM, to keep it within its max. efficient power power of 65 watts you would need to keep the current to about 5 amps. you could go higher in amps, may be 7-8 which brings the motor to its maximum power. Any more and the motor will overheat.

A gearbox would be needed or a very small prop, probably under 30 mm

Nick
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