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Question why this worm gear dc motor can't selft locking? can it be used for DOF drive

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by Arta Yasa, Jun 16, 2021.

  1. Arta Yasa

    Arta Yasa Member

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    hello everyone,

    I have built 2 wiper motors but with wiper motors of different specifications and power (big difference in body, and rpm). I took the initiative to look for another dc worm gear motor, finally found a former MIG Las. with specs 150rpm 24v dc. i have installed it in my 2 DOF. but the problem I encountered was that the motor could not self lock like a wiper motor. how do you outsmart it? but for the strength is better than the wiper motor. I'm afraid because motor can't self lock it can damage my BTS . because bts7960 maintains position at a certain angle. Any good suggestions for a worm gear dc motor that won't lock itself?

    Thank you, I hope I get a clue
    Help me sir @noorbeast Thank you.

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  3. Bontekop

    Bontekop New Member

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    According to the picture of the motor Voltage = 24 V, Current = 2.8 A . My estimation: max current = 5 - 6 A.
    According to the specification of driver BTS7960: Voltage 6-27 V, max current = 43A. So assume the current 43 A is at voltage = 6 V, then at voltage 24 V still a current max 10.7 A is available.

    So the bts should have no problem, but the weak link is the motor, it will stall when load is too high. Or it will not be able to keep the desired position (because it is not self-locking).
    When your motion system is well balanced, the nominal load on the motor will be minimal. It that case, maybe the motor can be used, but probably the motor will not be strong enough to reach the high speed of 150 RPM.
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    Last edited: Jun 28, 2021
  4. Arta Yasa

    Arta Yasa Member

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    after I tried it, I thought that the motor was strong enough to lock and move, but sometimes the motor didn't respond (like there was no power coming into the motor) I thought whether the bts7960 was shutting down, then I checked again in the smc3 utility on the pwm signal from the potentio was not there signal, sir. and on motors that have no response to information, motor 1 = off. and it's very hard to click to get it back on, sir. what's wrong sir? is bts7960 not strong? should i use 2 bts in parallel?? when I use a self-locking wiper motor the problem is the same. one of the motors arrived "not responding, I checked the smc3 utility for information, motor 1 or motor 2 = off. and it's hard to turn it on again. and the pwm signal has no response sir.
  5. Bontekop

    Bontekop New Member

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    I am not familiar with smc3 (yet).
    I don't think the BTS7960 is the problem, for me it looks like your motor is not strong enough.

    The motor is rated only 45 Watt. The nominal output speed is 150 rpm. This is rather fast, probably the gear ratio is 20:1. That means that the output torque will not be very high. For instance, if you would have the same motor but coupled to a gearbox with ratio 60:1, then this motor would be 3 times slower (50 rpm), but also 3 times stronger (output torque).
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  6. Arta Yasa

    Arta Yasa Member

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    Yes sir, but i have big wiper motor bus, with 50rom and very strong and selft locking. But the problem is same sir. Sometimes the motor cannot respond and the pwm from pot cannot detect on smc3utility sir