Problem: Motors shutting down

Hello

I have this weird problem that if my motors have continuous load (even slight) for the same direction for about 3-5 seconds, they shut down. They both have this problem but for one direction only. The other direction works just fine. They might start working after a while, or after arduino reflash or after re-powering psu. I am wondering if the problem is in my motor driver or motors or even arduino. I already ordered new cheap drivers and an arduino for test but not sure where the problem is. I'm using VW wiper motors with Moto Monster driver. PSU is HP DPS600PB so it shouldn't be the problem. What do you think? Could i fix it somehow?

I can say that the motors feel faster and more powerful to other direction. I tried to balance them like in following video but couldn't get them working same speed: Youtube
The weaker direction still does short-time movements fine without shutting down. And I also feel like the motors shouldn't stop as long as they are getting power from Moto Monster?

This problem prevents any kind of usage because one or both motors usually shut down in under half lap.
Here is a video of the problem (please have annotations enabled):

(Youtube)

Hi Jymä, please give us more information. Which Arduino code you are using? Which potentiometer did you built in?

I am using RacingMat's arduino code: http://www.xsimulator.net/community/marketplace/arduino-code-2dof-and-2-pins-direction-hbridge.67/ . Potentiometers are cheap B10K potentiometers, but they are very accurate if I turn them by hand and check readings from arduino. In the video I don't push the upper board down for long, but it resists no matter how long I do it. In the other direction they shut down in 3-5seconds. I also tried changing the direction of rotation by changing polarity of the motors. It just changed the weaker direction which shuts down motors to be the opposite.

If the cause cannot be found I think I will build all again from scratch with better motors and pots. :/ And maybe try different code though I don't think the problem is there. But maybe first try another cheap Moto Monster driver. I wouldn't still want to change Moto Monsters because I think the step up from them is quite expensive: Moto Monster 10€ -> 2 x 90€ JRKs.

IMO the code from RacingMat should work without any issues but I suggest to try out an other code to be sure:

http://www.xsimulator.net/community...3dof-motor-driver-and-windows-utilities.4957/

The SMC3 utility provides you PWMmin.
This is the minimum duty cycle that is used to drive the motors to their target position. Play with this value and report any results.

Regards
Pit

Great idea! That PWMmin function might get it working. I have to try it next weekend and report in.

EDIT: D'oh. Didn't receive my arduino jumper wires yet. Wouldn't want to solder all for that test. I try to test it the following weekend if I have the wires then.

I think I managed to test that PWMmin function with racingmat's code by changing this thing and putting 255 to everything:
// PID : calculates speed according to distance
pwm=195;
if (gap>50) pwm=215;
if (gap>75) pwm=235;
if (gap>100) pwm=255;

It actually made the motors shut down faster. I also tried turning the magnet base of the motor at the same time but it was already in the strongest position. I'm thinking that the motors are just too weak to that direction and it causes some kind of bug. I thinked of turning the brushes but it was too difficult because I couldn't disassemble the wiper motor easily anymore after welding. Whatever the real reason was, I ordered big DC motors from Motion Control in the UK. http://www.ebay.co.uk/itm/12V-DC-Ge...al_Components_Supplies_ET&hash=item58b2cd2323 . I should also get some spare Moto Monsters soon. I guess I have to reduce the PWM a lot compared to VW wiper motors which made barely any heat.

What happens, if you change the polarity?

PS: a screenshot of the SMC3 utility would be nice.

But now no more help is needed, because you ordered a new set of motors. IMO a good decision, it's better that way. When I saw your video according to my experience of needed forces for immersion all seemed a little bit too weak and wobbling.

If I change the polarity (and switch 2 pot wires) the weak and strong direction in the motors change. If they are weak to lift after changing polarity they are weak to lower. Hmm... Does that mean that the problem would be somewhere before the motor?

I didn't try SMC3 yet because I'm using Moto Monster as a shield and waiting for jumper wires to arrive. Don't want to solder all for that test. Maybe I should test wiper motors straight from PSU. But I think new motors will be a good buy anyway. Though it would be nice to solve this before installing them. If the problem wasn't in the motors I could sell them.

IMO yes.

Why not try out SMC3? The wiring is done in less than 5 minutes using diy wires and give you more experience (and works with Moto Monster). But If you want to wait for the right wires it is OK, I understand

This is the very first action I will do ever. I suggest never to build a system without testing the components before. Jm2c

Ok. I will do some testing next weekend and report here again. I had tested motors and everything alone with no stress, but now I have to test them straight from PSU and with stress to see if they shut down. If not, then try SMC3 and after that another Moto Monster when it arrives. These motors might still be good for some seat mover project. Full frame is maybe too much.

It may be that one of the safety feature of the monster moto card is being triggered, thus shutting down the motor. The fault is reset when u reset the ard or the power supply which is how ur able to restart the motor

I rewired Arduino and Moto Monster for SMC3. And that problem disappeared! I don't know what was the fault but for example I am using different PWM frequency now and all the buzzing disappeared too. Thank you for the help!
Though I have a new problem with Simtools and Arduino SMC3 communication now. I wrote about that to SMC3 thread. I have had pretty mysterious problems. If everything gets working I will probably use these wiper motors at first. Then see if the sim needs some structure modifications and update to those better motors too.

I was a little too quick on that conclusion. Today with more test I noticed that the motors shut down the same way, just not as easily as on the video. So it wasn't about Arduino code. It seems to be related to PWMMax. When the weaker direction reaches certain PWM for a longer period, motors just die. They die easier if I have higher PWMMax and I don't get good movement with low PWMMax. It is propably a safety feature of Moto Monster like Mazhar Salam said. Just that it seems to happen pretty much only to the weaker direction so changing those motors might help (weaker direction seems to need more PWM for same torque). I have ordered higher quality pots too.

I added some pictures. In first picture there is motion test without driver on the sim. In the end I start to pull the board and the motors die when the green (potentiometer position) drops the second time. The first drop is it just resisting my pull.
In the second picture I again pull the board against weak direction with more and more force and the motor tries to keep the position until it shuts down. In the last picture I have half of my weight on the motor against the strong direction and it resists (PWM never rises so high).

It does appear like the moto monster drivers are shutting down, although I am surprised... do you notice them getting hot?

Do the wiper motors have any built in electronics for speed control, if so perhaps that is what is shutting down.

In the wiper motor the ground wire goes directly to the brush, but the "high speed" wire goes there through a little coil. Should I try removing the coil? Also the motor brushes are positioned on 45 degrees angle to the dc motor axle. I think that's why the other direction is so much weaker, but they would be difficult to turn. The Moto Monster isn't getting too hot. I have a heatsink and a fan on it.

@Jymä Are you sure that you are driving your motors to the highest speed?how did you test it?brushes should be facing one to the other (180deg) for high speed take a look at this pic.about the coil i think you should remove it not sure.

@insanegr Yeah I'm pretty sure. I tested it on car battery first and I remember that the other one (~120deg) would have been faster. Like in this 1st picture. And the coils are similar to this 2nd picture. But I actually meant a single brush compared to the axle with that 45 degree angle. Like the "B brush" in this 3rd picture. Pretty confusing...

@juma you are right about the position of the brushes. at 120 deg is high speed. my wrong.

Unlike its name, Monster Moto is the weakest of all. While building a sim, the first thing we should know is to calculate the amount of CONTINUOUS power a control board is capable of handling.
http://www.xsimulator.net/community/threads/monster-moto-shield-amps-per-channel.5366/

Monster Moto can only handle 84 watts (continuous) power with a 12V power supply, which is not enough to move a sim. If you pull any higher than this through the card, it will overheat and shut down eventually.
When you increase the PWMMax, what is happening is increasing the current passing through the card. And when you keep the PWMMax below the 84 Watts, you of course do not have enough power to move the sim.

http://www.pololu.com/product/2502
Pololu Dual VNH5019 can handle 150 watts continuous at 12Volt

Pololu High-Power Motor Driver 18v25 can handle 300 watts continuous at 12 Volt -
This Card is what I am going to try next as it can handle enormous power without a heat sink but it does not include reverse power protection or any over-current or over-temperature protection. I assume if I dont keep an eye on the current and temperature, it will simpy catch fire and die.

(am not a fan of adding cooling systems...) also spend 20 minutes to type this in, let me know if it was of any help ... lol...

To be honest but this is b***s*** . One channel can handle up to 25A continuous, in a dual parallel channel mode the Monster Moto can handle up to 50A.

Sucessfully tested! I have two winches, each max. 750W and up to 120A, and they are running fine. Of course they need less for moving the seat so the maximum power needed in my rig is 40A for each winches.

www.xsimulator.net/community/threads/monster-moto-shield-acts-as-a-single-motor-driver-more-power.5482