need urgent help interfacing high current motor!

hi all,

hoping that you could help me in my project.

using an arduino to program a 24V, 4A continuous and 40A starting current dc motor. an accelerometer is connected to trigger the motor.

anyone can provide any advice in interfacing all 3 of these components together?

thanks in advance, Alex

I've recently done something very similar. Do you need to be able to reverse the motor? if not then something like a MXA066/MXA066 pwm controller will do the job if you want a ready made board. You can interface with the board by replacing the speed pot with a simple circuit that takes a 5v PWM signal from the arduino and turns it into a filtered 0-12v signal that can be fed to the board (Much respect must go to Grumpy Mike for his help :) Alternatively you could make your own controller for the motor.

Hi daveg360,

Yeah. I'll need to be able to reverse the motor too. I've got the coding pretty much worked out but the 40A starting current of the motor is quite troublesome. Is there anything that you'd recommend to do this?

The works of the project is pretty similar to this video. Tilting the accelerometer in one direction will make the motor rotate clockwise and vice vesa.

http://www.youtube.com/watch?v=EwLEWcVnLeg

PS: Is it hard to make my own controller?

Thanks so much :)

If you're looking for building-block components for switching 40A, you could drive a transistor that drives a relay. Or you could setup a darlington pair with a high current MOSFET.

You could look at "soft start" circuits to limit the inrush current when you start it up or change direction.

Basically they apply the voltage to the motor as a ramp rather than a fast rising edge.

Can this be done through a PWM speed controller Mike? so for example you'd always ensure that the speed was set very low at startup/direction change etc?

hi and thanks for all the replies. really do appreciate it. :)

unfortunately, i'm still pretty much new to all this. sorry :(

could i use this http://www.pololu.com/catalog/product/755/specs does it fit within my requirements? i chose this because its the easiest available one i could find on such short notice in my area.

thanks for all the advice!

You still have a starting problem with that don't you? I've never designed/built one but I thought some sort of capacitor-assist startup circuit was typically used for this type of problem.

After a quick search... hard start kit like this: http://azpartsmaster.com/Products/Supco-SPP6-Super-Boost-Hard-Start-Kit__SPP6.aspx

Can this be done through a PWM speed controller Mike?

It would not limit the initial surge as you would still get a surge of 40A by applying full voltage in a pulse. Normally these things are done by applying the voltage slowly as a ramp.

@LegoMe The motor controller you posted has a IRF7862PbF FET in it. I just looked up the pulse current limit in this and it is 170A so this could be suitable for your motor controller.

do i really need some sort of a booster? or is it possible to just get one driver?

sorry guys i'm way lost in this thread. :( i'm very much new to this and it's my first time immersing myself in all these electronics.

i know this is asking alot but could anyone provide a quick fix to this or perhaps a schematic of some sorts?

thanks you all so much.

@LegoMe The motor controller you posted has a IRF7862PbF FET in it. I just looked up the pulse current limit in this and it is 170A so this could be suitable for your motor controller.

hi mike,

however it is stated that usage of 24v batteries are not recommended. could you tell me how to set this up? (: thanks!

Hi guys,

I've been searching around and came across this other motor driver. http://www.dimensionengineering.com/datasheets/SyRen10-25.pdf

Here are some of it's features.

25A continuous, 45A peak Synchronous regenerative drive Ultra-sonic switching frequency Thermal and overcurrent protection Lithium protection mode Input modes: Analog, R/C, simplified serial, packetized serial Size: 2.4” x 2.3” x .8” (61 x 58 x 21 mm) Weight: 55 grams

Can it work with my motor since it has a peak of 45Amps?

hi anyone can help? (: