Author Topic: DC Motors specs  (Read 2385 times)

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Offline vidamTopic starter

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DC Motors specs
« on: June 03, 2008, 12:44:24 PM »
I am searching for the best DC motors (stepper or brushless) for a speed controller that is rated for the following:
# 14V to 48V voltage supply (50V absolute max, down to 6V with external 12V supply)
# 80A continuous current each channel (150A peak 5 seconds)
# Adjustable current limit from 10A to 130A (sets the limit for both channels)


The max continuous current on this Scorpion 4025-16 Brushless Outrunner Motor is rated at 75 Amps.

This is < 80A continuus current on each channel supplied from the speed controller.

http://www.rcdude.com/servlet/the-713/Scorpion-4025-dsh-16-Brushless-Motor/Detail

Also I read the Actuators tutorial: http://www.societyofrobots.com/actuators_brushlessmotors.shtml

And am confused on what kind of special speed controller is needed for brushless motors due to induction? It wasn't clear.

Thanks,

Melanie
« Last Edit: June 03, 2008, 01:03:51 PM by vidam »

Offline benji

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Re: DC Motors specs
« Reply #1 on: June 03, 2008, 02:14:01 PM »
actualy people search for a controller based on the motor they have,,thats because they chose the motor according to how much torque,pwer,speed they seek....
searching for a dc motor for your driver ,,well based on what? your controller has maximum ratings,,u want that?
i dont think you would need a dc motor with 80 AMPS ,,,amps means torque ,, voltage means speed

as long as i dunno whats it gonna push and how fast it should go then i cant suggest you one,,,
i think you can only choose your motor just watch out it doesnt go above the maximum ratings u mentioned above


 
good ol' BeNNy

Offline vidamTopic starter

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Re: DC Motors specs
« Reply #2 on: June 03, 2008, 02:27:17 PM »
actualy people search for a controller based on the motor they have,,thats because they chose the motor according to how much torque,pwer,speed they seek....
searching for a dc motor for your driver ,,well based on what? your controller has maximum ratings,,u want that?
i dont think you would need a dc motor with 80 AMPS ,,,amps means torque ,, voltage means speed

as long as i dunno whats it gonna push and how fast it should go then i cant suggest you one,,,
i think you can only choose your motor just watch out it doesnt go above the maximum ratings u mentioned above


Appreciate the info... speaking generally of course, you say amp means torque and voltage means speed. Can you please explain that further from a mathematical standpoint or from any way you want.

How to calculate how fast a robot/machine can travel with 50 Volts juice available to the motors, neglecting gear ratio, and robot mass?

How to calculate the torque output from a robot/machine with 130 Amps again neglecting friction, robot weight etc.


Offline benji

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Re: DC Motors specs
« Reply #3 on: June 03, 2008, 02:39:15 PM »
well, dc motors in general are coils inside magnetic fields
the voltage becomes across the coil , and the current runs through it,, now
the next step and the butter of all that is the laplace equivalants about how the magnetic field affects a wire with electrones runnin through it
(it pushes it in some direction)
and because the wire here is a coil(rounded wire) it turns

the oposite happens when a moving circuit is moving inside a magentic field , current happens to run in this circuit

to calculate how many turns per minute (how fast) your dc motor runs under 50 volts you should get the constants of your dc motor's coil and solve the laplace force equations

google laplace force or dc motor equations

« Last Edit: June 03, 2008, 02:41:16 PM by benji »
good ol' BeNNy

Offline vidamTopic starter

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Re: DC Motors specs
« Reply #4 on: June 03, 2008, 02:59:00 PM »
well, dc motors in general are coils inside magnetic fields
the voltage becomes across the coil , and the current runs through it,, now
the next step and the butter of all that is the laplace equivalants about how the magnetic field affects a wire with electrones runnin through it
(it pushes it in some direction)
and because the wire here is a coil(rounded wire) it turns

the oposite happens when a moving circuit is moving inside a magentic field , current happens to run in this circuit

to calculate how many turns per minute (how fast) your dc motor runs under 50 volts you should get the constants of your dc motor's coil and solve the laplace force equations

google laplace force or dc motor equations




Thanks, but I can't find anything for laplace force equations under google. Do you mean Lorentz Force Equations like this one:
http://en.wikipedia.org/wiki/Lorentz_force

Offline benji

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Re: DC Motors specs
« Reply #5 on: June 03, 2008, 03:18:28 PM »
the funny thing is i found it in the french wiki

http://fr.wikipedia.org/wiki/Force_de_Laplace

not bad, u can still recognize the equations

and yea lorentz and laplace forces are pretty much the same
good ol' BeNNy

 


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