Denso Window Motors, Warning - Don't use with Jaguars !

[Ether]

Since it's been a while since there has been any activity on this thread, and there were over 70 posts, I took the liberty of excerpting some of the observations and problem descriptions that have been posted. The number before the right paren is the post number.

Considering DavidGitz's post#55, it would be most interesting to get an answer to EricVanWyck's question in post#74

Also, has anyone experienced this problem with BLACK Jags and window motors? See post#4.

1) diviney

...Denso window motors that came in this years KOP. ...This motor used a Jaguar controller...

...the motor will occasionally simply fail to respond to the controls. When the motor fails to respond, there is a voltage present on the input to the motor. We could hear a high-pitched sound from the motor as further indication that it was being powered.

There was no mechanical interference, yet we found that there was sort of a mechanical hysteresis taking place. If the arm was commanded to go down, but was unresponsive, we could gently push it up with our finger and that would cause it to properly drive down in response to the command. Likewise, if the arm was commanded to go up, but became unresponsive, we could nudge it down and it would respond by driving up as commanded.

We tried a spare motor, but if anything it was worse with the replacement motor.

This is not a fluke due to a bad Jaguar or a bad motor because we saw it with 2 different motors and 2 different Jaguars.

we substituted a Victor speed controller, and everything then worked perfectly.

One final observation - we were not able to get the motor to fail by simply commanding it on and off. By using the joystick to vary the speed up and down, forward and backward, it would fail readily. If you are not varying the speed and just want forward / reverse on / off, you [might] be OK.

Both of the Jaguars we tried are the older brown ones. We have not tried this on one of the newer black ones.

4) big1boom

We are running 3 Denso's off of 3 Black Jaguars on CAN, and have had absolutely no problems with them.

5) Mr.G

We are using all victors this year... The problem occurs for us when the motor gets hot.

9) diviney

switching to a Victor has completely eliminated the problem.

54) Kingofl337

We have noticed the stalling issue which causes the motor to stop moving but keep overheating.

Our fix was to monitor the wheel and disable the PID control for 1 second if it stalled. Once the PID is re-enabled the motor behaves normally

55) DavidGitz

sometimes when the robot is rebooted (after allowing a lot of time to cool down, i.e. the motor is cool to the touch) the window motor will not move anyways. If we disable and re-enable it will come back and start working.

61) billbo911

We know the Victors work well with the window motors and have for years.

The window motors work well with the Spike relays.

66) diviney

The Denso motor fails to start reliably even when 100% drive is applied (and the PTC is not tripped). The voltage waveform is correct, and the current is high. It just acts like it's stalled even though there is no mechannical load. We can easily get this to happen with just the motor (nothing connected to the output shaft).

The motor does not start even if you try to "help" it move in the commanded direction.

When the motor is "stuck" like this, you can coerce it to start by turning it in the OPPOSITE direction. A slight nudge in the opposite direction makes it suddenly free up and turn in the commanded direction. It is as though there is some sort of backlash in the worm gear, and shifting this backlash causes a release of tension, freeing the motor to turn in the opposite direction.

We can NOT get the motor to fail in this way with a Victor powering it. There was some mild evidence of sticking, but it always freed up with a command authority much less than maximum (maybe 25%) wheras the Jag could not start even with maximum command authority, happily drawing > 10 amps (until the PTC tripped after many seconds).

With the Victor, the motor growls as it begins to start. With the Jag, it's a high pitched squeal. Could it be that the growling vibrates the worm gear enabling it to move the backlash just enough to start when the high-frequency of the Jag cannot?