Problems Building H-Bridge Circuit on Breadboard

Thread Starter

YoungCheung05

Joined May 20, 2019
3
I have been trying to build a BLDC motor using an H-Bridge Circuit, based on the instructions from https://www.instructables.com/id/BLDC-Motor-Using-PVC/ and the attached schematic. I think I'm close, but my circuit is not working correctly -- the power isn't running through the circuit from the batteries. I've tried isolating each of the four quadrants to see whether they work, but have frustratingly found some individual quadrants work sometimes but cannot figure out the problem. I've attached the setup on my breadboard to this post as a pdf printed from a layout I drew on fritzing. I suspect that it has something to do with the way the ground wires are setup, but I haven't been able to figure out the problem. I would very much appreciate any help or insight that anyone may have.
 

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danadak

Joined Mar 10, 2018
4,057
Do you have a scope shot of the drive signals from the Arduino and
the load used in the bridge ? Use a 100 ohm R in the bridge for a
load when you do the measurements.

Regards, Dana.
 

Thread Starter

YoungCheung05

Joined May 20, 2019
3
I'm not sure that I'm answering the question correctly, but (admittedly just based on the instructions) I'm using a Hall sensor to detect the alternating disc magnets on the rotor, which should then cause the polarity to switch through the H-Bridge & the arduino script. The Hall sensor is working correctly, as is the arduino script, which leaves me with the lack of current running properly through the H-Bridge.
 

wayneh

Joined Sep 9, 2010
17,495
I'd take the Arduino out of the picture and verify by hand that applying your on/off signals actually accomplishes the switching that you want the MOSFETs to do. If that all works well, then you know where to look.

How much current does your motor require? Breadboards aren't meant for much current and funny things can happen.
 

danadak

Joined Mar 10, 2018
4,057
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