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Difference between 2 DC motors

Posted by jomac 
Difference between 2 DC motors
December 01, 2015 11:39AM
Ive a pretty sound electrical/electronic background but i'm a little confused between the specs of 2 motors.

One motor is rated 12v @ 80 amps, speed 4100 rpm
The other motor (from the plate) says 24v 5100 rpm 4 amps 350w (?)

The first motor was used for starting model aero engines, larger sized via a rubber coupling. So using the data on the plate, this motor would be rated at 960 watts. However the other motor says 350 watts, but only 4 amps, a Chinese typo? The second motor, the 24v one was used in a 4mph mobility scooter.

However, the confusing thing is that the 'theoretically' more powerful motor, the 12v one is about 10-15% smaller in physical size.

I want to use the more powerful one, but which one do i believe?

Re: Difference between 2 DC motors
December 01, 2015 02:30PM
I strongly suspect that the 80A is either a typo or is the starting current and not the running current. I don't believe anyone in their right mind would design a 12V motor rated at 80A continuous running current. If you wanted 960W power, you would design for a higher voltage and lower current.

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Difference between 2 DC motors
December 01, 2015 04:43PM
Starter motors are rated for 1min runtime. The magnets will suffer running them too long and overheat them.
The Scooter motor is rated for continuous running. They can deliver much more power for a short time as well.
It all depends on the brushes ( size and quality ) and a matching controller ( preferably with current limitation )
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