Question One of my IBTs is getting too hot

Hey guys have you had any issues where just one of your ibts_2s are getting hot just doing the initial testing in smc3 utils ?

could really do with some help not sure what could be causing it.

i know its not pulling too much current as i have 25Amp inline fuses and these have not blown.

i have checked my Arduino wiring and all seems to be as per the diagram on the SMC page.

i have also replaced the ibt to make sure it wasn't a faulty one.

thanks

29 Ford

thanks for this Noorbeast. looks like i was potentially running my Fpwm too high at 35kHz rather than 20kHz

however still heats up so maybe will have to try this heat sink bit mentioned in the post thanks

Sorry for the long delay.

I have now heat sink compounded the heatsinks and got a fan blowing ait over them to cool them this has helped slightly but still struggling with thermal shut down.

However whilst I have been looking through everything these last couple of weeks I have noticed my smc3 utility is showing me some data that may be the problem





On motor 2 I can move the hall effect sensor and the green line shows it moving.

But if I switch to motor 1 and move the motor 2 hall effect pot it shows it moving.

Could this mean the arduino could potentially be trying to drive both motors against each other causing the heat. Or is this normal for the hall effect to show in both motor windows?



Edit: my oscilloscope does not show this it shows two separate hall effect sensors

Cheers

They are normally centred at neutral ride height. This is with the motors off and the rig at full droop or rest. Which is why they are at the top of the scale.

Could you confirm I should only see one hall effect in each chanel on smc3 utility? As my scope is showing them separate.

I think this is highly likely where my issue could be coming from. Might have to get all the parts back on the test rig at this rate. And go back to basics.

SMC3Utils cannot control two motors at the same time, it always controls only one motor .
If you want to show something from SMC3utils screen then post screen captures instead of photos ( photos are too blurry and unreadable).
To reduce the heating of the IBT2 you can gently sand the varnish from the bottom of the IBT2 I'll post a picture, just put a thermal paste such as GD800.

I did the mod to the ibts with thermal compound which did help slightly.

I will try get some better screen shots. But my issue seems to be that say I move pot 1 which is attached to motor 1 that shows as the green movement in motor 1 when monitoring on smc3

If I now switch to monitor motor 2 I can move the motor 1 pot and that still shows as a moving green trace this is what I think my issue could be. But not sure how.

I know smc3 can only control 1 motor but surely it should be sampling motor 2 pot when you are viewing/controlling motor 2. So I think there may be an issue with wiring or arduino possibly.

Hey,

what kind of motors are you trying to control? Voltage, Watts etc. would be helpful. Also can you make some photos of the connections of cables to the IBT etc.?

Ben

Sorry I'm really bad at writing what I'm trying to say I know it can control 3 motors but only monitor one. I just don't know why my pot signal from motor 1 is showing its movent when monitoring motor 1 or 2

The motors I am running are a 24v wheelchair motor.
520w each

They are wired in 10gauge silicone wire
And the data and 5v power for the ibts are all run in 26gauge.
102950

Missing wire from A0 to potentiometr 1 ?

Dont set PWMmax above 140-150 520W motor burn your IBT2

Unfortunately not it's definitely there and connected.

Thanks for the tip. I only have them at 100 at the moment but u haven't even sat in the rig yet so guessing I will need a bit more. But good to know that's where I should stop

Ok , well that leaves one option , unsolder the cables from the A0 socket and then check if you have a correct reading from the second potentiometer ( just don't accidentally turn on the power to the motors)

OK so it turns out my pot issue was down to the fact I was disconnecting one to isolate them for testing and smc3 displays the value of the pot on every monitoring motor channel if only 1 pot is connected once I connected them both up at the same time they are behaving as expected pot 1 shows on channel 1 and pot 2 on channel 2

Good to hear it, we look forward to the completion of 2DOF and the video.

So I've taken a short break from the rig after being disheartened frying 4 ibts.

And comeback to it with not much more success however I have been watching alot of videos where people's rigs stay in a centred position. Meaning the motors are not constantly driving to stay there. ( that's what I believe)

My rig always self drives down under it's own weight the the lower stops rather than staying at centre so I wondering if my motors are having g to work hard just to stay on centre to fight the driving down nature of my rig.

My gearboxes on my wheelchair motors are 19:1 could this bee an issue? I see most people using 25:1

Thanks
Dan