Synchronous Denso Motors

[35Billy42]

Hey everyone! My team is trying to run two denso motors in sync, but we're having a little trouble. Our motor controllers are set to brake, but one denso motor's brake seems to be not working. Sometimes one motor seems to be moving faster than the other. Any suggestions?

[Ether]

Originally Posted by 35Billy42

Hey everyone! My team is trying to run two denso motors in sync, but we're having a little trouble. Our motor controllers are set to brake, but one denso motor's brake seems to be not working. Sometimes one motor seems to be moving faster than the other. Any suggestions?

The best solution is to physically connect them to the same shaft, if possible.

[35Billy42]

Are there any other options? I don't think connecting them is even a considertion on my team.

[Ether]

Originally Posted by 35Billy42

Are there any other options? I don't think connecting them is even a considertion on my team.

Put an encoder or pot on each motor and use software to make them operate in sync.

[yara92]

we hav 2 mtores difrent speed
my team count the RPM for each moter many time then we use the program to mange Synchronous

[jimwick]

I assume you are talking about the Denso window motors.

We are working our way through this problem right now. We are using two window motors to wind up our shooter. Originally they were on the SAME SHAFT and they failed. DO NOT PUT THEM ON THE SAME SHAFT. What happens is that they don't run at the same speeds, one motor tries to do all the work and locks up, then second tries to do all the work at it locks up. Then neither will go forward or backward.

So what we are doing is putting them on separate shafts. We are counting revolutions and plan to put them on separate controllers and have them stop when they get to the proper place. Then even if they don't run evenly they will at least get evened up at the end of each cycle.

We have been running these manually and have succeeded in making them perform the intended function under manual control. The counting revolutions and control functions still need to be implemented. But at least they are now physically working without problems.

[ice.berg]

Our team LOVES the window motors. The biggest weakness of them is just the mounting, after that we really do enjoy using them. 3 of our past 4 robots have used 2 of them in pair directly attached to the same shaft and we have had no problems. Obviously you have to make sure that both the motors are running off the same type of controller as well as moving on the same signal (we have usually just used a Y pwm cable to make sure of this.) Yes the motors do have some variance in speed but when put on the same shaft they are close enough that it should be fine if you make sure all the electronics and programming are synced properly.

[Lil' Lavery]

Originally Posted by Ether

The best solution is to physically connect them to the same shaft, if possible.

With other motors, yes. With the Denso window motors, no. The Denso window motors are nigh impossible to back drive, thanks to the worm gearing built into the housing and anti-backdrive pins. Mechanically linking them together is a recipe for damaged window motors or hardware. The only way I would link two window motors together is with a smooth belt.

[xXhunter47Xx]

Originally Posted by ice.berg

Our team LOVES the window motors. The biggest weakness of them is just the mounting, after that we really do enjoy using them. 3 of our past 4 robots have used 2 of them in pair directly attached to the same shaft and we have had no problems. Obviously you have to make sure that both the motors are running off the same type of controller as well as moving on the same signal (we have usually just used a Y pwm cable to make sure of this.) Yes the motors do have some variance in speed but when put on the same shaft they are close enough that it should be fine if you make sure all the electronics and programming are synced properly.

This is basically what we've done with ours and there are no problems so far.
SO FAR.
SO. FAR.
Dear God if this thing breaks tomorrow.

[Nirvash]

Just another point of view, in 2011 our team directly connected two window motors on the same shaft and had no issues. This was with the locking pins removed. (Other then them being weaker then we would of liked)

[DjScribbles]

Using feedback is the best way to go, but the following can help if that is outside your teams capabilities:

You might try using a split-PWM cable (one PWM output driving both motor controllers, with the output of one of the motor controllers reversed if needed); this would rule out any software/timing issues.

You should also try calibrating your motor controllers, to rule out the possibility of variation in the calibration causing problems.

Also, the motor controllers absolutely have to be of the same type (i.e. two talons, two victors888s, or two jaguars)

[FrankJ]

If you wanted the same voltage going to both motors, you can power them of the same controller. I understand the right hand one is wound slightly differently than the left hand one so they will naturally turn at slight different speeds if they are not the same hand. I understand if they are on the same shaft you need to remove the locking pins to keep them from binding.

[Ether]

Originally Posted by xXhunter47Xx

This is basically what we've done with ours and there are no problems so far.
SO FAR.
SO. FAR.
Dear God if this thing breaks tomorrow.

Remove the locking pins, and drive both motors with one controller (use a PWM Y cable) and you should be fine... assuming the load doesn't exceed the motors' capability.