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Amp draw , battery direct to motor vs thru ESC

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Amp draw , battery direct to motor vs thru ESC

Old 09-11-2003, 09:09 AM
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woodduck-RCU
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Default Amp draw , battery direct to motor vs thru ESC

I recently purchased a Super Whatt meter and connected a 1800 mah nimh battery to a Zagi speed 400 thru thru the Whatt meter to a Great Planes 50 amp ESC. My amp reading was 10.8 - 11.2 amps
I removed the ESC and connected motor directly to battery thru the Whatt meter and my amp reading was 5.5. This does not make sense! Any help will be appreciated.

Thanks Woodduck
Old 09-12-2003, 07:55 PM
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rogwabbit
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Default RE: Amp draw , battery direct to motor vs thru ESC

was it spinning the same speed? did you change props? you sure those numbers are right? seems odd.
Maybe a frequancy differance caused the meter to read incorrectly?
Old 09-13-2003, 01:56 AM
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Default RE: Amp draw , battery direct to motor vs thru ESC

Also, make sure its spinning the same direction for both measurements.
Old 09-13-2003, 04:30 PM
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woodduck-RCU
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Default RE: Amp draw , battery direct to motor vs thru ESC

I made no changes! Neither the prop nor direction changes, both measurements were
made with a fully charged 1700 mah nimh battery. The connectors are Deans so I could not change the direction. The motor is reverse timed and that is the direction for both tests. The prop is a Gunther 5 x 4.5

Thanks for the replies.

Woodduck
Old 09-15-2003, 08:08 AM
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Matt Kirsch
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Default RE: Amp draw , battery direct to motor vs thru ESC

The only way for there to be such a drastic difference is for the motor to be running in the "suck" direction for one test and the "blow" direction for the other, AFAIK. Taking the ESC out of the equation should actually increase the current because you no longer have the associated losses. The ESC definitely doesn't do anything to boost the current.

I'm thinking, if you used Deans between the battery and ESC, and the ESC and motor, it would be pretty easy to have it wired such that the Dean's connector is wired "backwards" on the motor. That is, the marked + terminal on the Dean's is connected to the actual + terminal on the motor. To get proper motor rotation for the Zagi, you would've had to wire the Dean's "backwards" on the output end of the ESC. So, when you connected the battery directly to the motor, you connected it + to +, - to -, and the motor ran "forward." Advanced timing in the reverse direction is retarded timing in the forward direction, so the current would be lower.

Please check again and make sure the motor is blowing air in the same direction in both scenarios. I know my sense of spatial relationships get messed up from time to time, maybe yours did too?

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