powerlock motor act funny

Go To Last Post
7 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Strange problem occure when I tried my remote controlled car alarm in the real world. When I drive the centerlock motor it works as it should but after that it immediately get back again. Or more likely it's in a middle position between lock or not lock.
Why in the earth that motor get a little bit back after driving is over? Motor is connected in LSP3,4

sequence in locking:
1. relay K1 set's the direction
2. wait 0,3sec
3. set relay K2
4. wait 0,8sec
5. release K2
6. wait 1sec
7. release K1

Regards
heguli

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Strange indeed .... could it be a mechanical issue? I see no electrical reason (yet)
Once the lock is in lockposition, the motor tries to push it further .... springload-effect; once the power is taken off, the spring releases and spins the motor a bit back.
Shorting the motor when done would prevent it.

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
could it be a mechanical issue?
Noup, after locking I tried to pull that door knob(or what it is in english?) up and I had to really pull. When the knob is in a high position it's rigid. So, this means the motor pull the knob down by it self. Well, atleast that's how I see it.

Quote:
Shorting the motor when done would prevent it.
Shortly motor takes about 3A current. What would be appropriate way to do it? Do you think that motor is charged and somehow the current circulate backwards after drive is over?

Regards
heguli

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
Do you think that motor is charged and somehow the current circulate backwards after drive is over?
That was the first idea that popped up in my mind. But after a little thought I abandonned the idea. The current will try to keep flowing in the same direction. And thus prevent spinning back.
I wonder if I expressed myself clear on the spring-effect. Let me retry.

The motor brings the knob from unlock to lock-position. Once it's there, (apparently within the 0.8 second), the motor is still trying to push it further, but the mechanism prevents that. Motor is strong and pushes through, bending the mechanism a bit (like a spring). Once the motor is powerless, the mechanism gets the chance to release the tension, spinning the motor reverse. Inertia (flywheel-effect). Motor is powerless, and thus will not brake. When tension is back to zero, the motor is still spinning (nothing is there to stop it), and brings the lock halfway to unlock.

I hope it's clear now.

Wipermotors suffer from the same effect. That's why they have an auto-brake when made powerless.

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I do understand now what you are meaning. Tomorrow I'll take motor off the car and try again. If it doesn't get back while it's removed then the fault is in a mechanical part.

Quote:
Wipermotors suffer from the same effect. That's why they brake it when made powerless.
Probably depend the car. Mostly there is a angle transmission inside and that itself is a brake.

Regards
heguli

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I took power directly from the battery, drove all the five motors at the same time and they worked fine. I placed the burglar alarm back and same thing happend... didn't work. After heavy duty trying 3.15A fuse(F2) blow up and also relay K1 driver pin at atmega blow up too. Ah, EEPROM was messed up too.
Check out the schema and specially D1, which is 1N4007. It's rated to 1A for a continue use. Could that mess everything?

Regards
heguli

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
Could that mess everything?
Depends what you connect to LSP1 and LPS2.

Car-battery is NOT a clean power-source. I think you need to do more on filtering and protection.
From what you describe, I think a high voltage spike on the 13.8V went through K1, through T1's collector-base, straight into the Mega.

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips