MC33035 problem..forward and reverse speed

Thread Starter

hl2xgw

Joined Apr 10, 2020
4
Hi. everyone.

I designed like fig.39 on data sheet.
I used high side fet IRF5210 and low side fet IRF1310.
Rt is 4.7kohm, Ct is 10nF.
fosc is about 24kHz.

I had some problem at start.
It is solved, I used sensor resistor 0.05R.

It runs very well. But I have another problem.
forward speed differ with reverse speed.
when reverse mode is run, hall sensor pulse frequency is about 1.2kHz.
but forward mode is run, hall sensor pulse frequency is about 680Hz.

How can I match the two frequency?

please help me.

thanks.
 

Thread Starter

hl2xgw

Joined Apr 10, 2020
4
Hi ericgibbs.
Thanks. your reply.
I already have this files.
And I make my PCB.
Some BLDC runs well, some BLDC runs as above.


Has anyone had this experience?
Hi, Posted the d/sheet so that others would have direct access to the circuits, should help the replies. ;)
 
Last edited by a moderator:

shortbus

Joined Sep 30, 2009
7,669
Are you also using the MC33039 chip in the control? Is the motor under a load, something that may have a greater load, resistance to rotating, in one direction?
 

Thread Starter

hl2xgw

Joined Apr 10, 2020
4
Hi ericgibbs.
Thanks. your reply.
I already have this files.
And I make my PCB.
Some BLDC runs well, some BLDC runs as above.


Has anyone had this experience?
Hi, Posted the d/sheet so that others would have direct access to the circuits, should help the replies. ;)
Hi...
I misunderstood.
Thanks for letting me know.
 

Thread Starter

hl2xgw

Joined Apr 10, 2020
4
Are you also using the MC33039 chip in the control? Is the motor under a load, something that may have a greater load, resistance to rotating, in one direction?
Hi.
Yes. I use MC33039.
Motor has some load.
Motor has bevel gears. and opposite side of gear is straight bar about 20cm.
Motor turns this bar. forward or reverse.
 

shortbus

Joined Sep 30, 2009
7,669
Motor has bevel gears.
If your gears shafts aren't properly in line(not on the same center line, one of them offset) there can be more drag/resistance in one of the motions forward or reverse. This would be due to less backlash in one direction compared to the other.

Have you tried measuring the pulses/speed without the gears meshing? Just the motor only.
 
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