'Soft-starting' a DC motor, is this the solution??

djgyro1

Apr 28, 2011
3
Joined
Apr 28, 2011
Messages
3
Hi all, fairly new to messing about with electronics so please bear with me :)
I need a control device to in effect 'soft-start' a 24v DC permanent magnet motor rated at 375w and 22.5A
SK Pang do a Pololu High-Power Motor Driver 18v25 CS, the link is below. I have contacted them but they are rubbish at replying and various searches on Wikipedia haven't helped me understand anymore about the electronics in the unit.
Do I need some extra equipment to 'program' this board or is it done with dip switches?

http://www.skpang.co.uk/catalog/product_info.php?cPath=159_161&products_id=662

If anyone has other thoughts about what I could use instead I would be very grateful, I assume PWM is the only way to 'soft-start' DC?

Rgds, Ben

 

awright1

Aug 9, 2005
53
Joined
Aug 9, 2005
Messages
53
PWM is not the only way to soft start a DC motor but it is certainly the most efficient way in most cases.

If you just want to soft start the motor and have no servo control requirements, I would think any basic PWM generating IC driven by a ramp and driving a single IGBT or MOSFET of sufficient current/voltage ratings would do the job.  I haven't actually done this myself, so do not have design details to offer but I don't think a great deal of sophistication is required.

If you want something that's been designed for you, look at this CANA-KIT <http://www.sparkfun.com/products/9668>, a 24 volt 50 amp basic PWM controller with built-in soft start function.  A brief instruction manual (not including dircuit schematic) is offered at that site.  $59.

awright

 

djgyro1

Apr 28, 2011
3
Joined
Apr 28, 2011
Messages
3
Thanks awright, I spoke to Canakit last night and have ordered one of the modules you suggested :)

Rgds, Ben

 
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