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DRV10983, BLDC motor driver

Other Parts Discussed in Thread: DRV10983

I have few doubts about DRV10983:-

1)How I will get maximum speed(In my application it has to get a minimum speed of 1500 rpm but i stucked at 750rpm)  of Runtian motor on maximum load? Can any suggest me to change any default settings of motor that might helpful to me. 

2)I connected another bldc of mine to DRV10983 for a fan application what's the problem I'm facing is that I'm not reaching the maximum speed(I'm getting 800rpm only,It doesn't reach its maximum ratings also,while I measured I get V-12,I-0.85) on load.So,Can anyone suggest to overcome this and my motor specifications are given below:-

 The specifications of bldc are:

 Operating voltage-24,Current-2.1(Max.),RPM-2000(on load),Pole-10,Phase resistance -0.7.

  • Hi Sai,

    Our experts on this device have been contacted and should reply soon.
  • Sai,

    You should be able to 1500rpm with Runtian motor on-load at 12Volt. In order to assist, please provide following:

    1. How are you applying speed input, it via GUI or via POT on DRV1083 EVM?

    2. Share the basic and advacne page setting images.

    3. It would be good if you can share Motor input phase voltage and current waveform  at max speed.

    With experiment with your motor, you must supply right values of Phase Resistance and phase-phase velocity constant Kt. Follow the tuning guide to know the procedure to meausure Kt.

    Best Regards

    Milan-Motor Application Team

  • Hi Milan,

    1. I'm controlling the motor through POT.

    2. I changed few basic settings (phase resistance,Kt for max rpm)  also,kindly please do needful:

    Basic settings image:

        Advanced settings image:

    3.Later I will share current and voltage waveforms.

    4.I followed tuning guide and I measured the right values and applied to motor but it is not getting its rated rpm on load(I'm facing a common problem in both motors i,e I'm achieving half of their rated speed)

  • Sai,

    Let's first resolve issue with Runtian motor. Since your are driving it with load, the origanal setting needs modification. Keep the original values of  phase-resitance 1.23 ohm, phase-phase Kt 55, all closed loop and start-up setting parameter and Try following:

    on Basic setting page: Disable acceleration current limit

    On Advance setting page: Increase the lock-detection setting to max-3.2amp. disable current limit and closed loop stuck. Reduce the deas-time to 80nsec.

    I hope these setting will help you to increase the speed with Runtian motor.

    Best Regards

    Milan-Motor Application Team

  • Hi Milan,

    Thanks for those settings information.

    I replaced those settings which would helped to increase my speed from 750 to 830 rpm at this instant I taken voltage and current ratings,they are V-12v,I-2.5A.

    I noticed few things here:

    1) Motor gets too much heated after sometime.

    2) Driver also gets heated and motor off for few seconds and runs for some time and again off(continuously  going on............so I arranged a cooling fan to driver so this case is not repeated again)

    Can you explain why those happened?

  • Sai,

    With test conditions mentioned in your post 12V/2.5Amp, it's clear that the DRV10983 current is beyond continous current rating of 2Amp. There is high probality DRV10983 is going into Thermal Shutdown hick-up mode.

    The DRV10983 has a built-in thermal shutdown function, which shuts down the device when junction temperature is more than TSDN ˚C and recovers operating conditions when junction temperature falls to TSDN. Refer to section 9.3.2.1

    You will have to reduce the load on motor, it is byond rating both Motor and device.

    Best Regards

    Milan

  • Hi Milan,

    Thanks for your information.

    Coming to my bldc I'm not reaching the maximum speed(I'm getting 850rpm only,It doesn't reach its maximum ratings also,while I measured I get V-12,I-1.2 ) on load.So,suggest any settings for me to overcome this and my motor specifications are given below:-

     The specifications of bldc are:

     Operating voltage-24,Current-2.1(Max.),RPM-2000(on load),Pole-10,Phase resistance -0.7.

  • Sai,

    What is back-emf constant Kt for your motor, phase-phase VPk/Hz? You must put the right value of this in GUI to get proper operation.

    Back-emf constant dictates the maximum operating speed at given input voltgae Vcc. If your motor back-emf constant is such that it require 24Volt to reach 1500 rpm, at 12Volt motor will never reach rated speed.

    Best Regards

    Milan-Motor Applicaiton Team

  • Hi Milan,

    Back emf constant Kt is 57 mv/Hz.

     While I'm operating with 24v I'm facing a new problem i.e.,when pot reached 70%(near by) of its rotation for varying speed suddenly motor is stopped,if pot rotation is less than 70% motor is rotating at constant speed.At this time my readings are:

    V-24, I-1.2, RPM-900.

    While I'm increasing pot more than 70% current is fluctuating from(0.7-1.3).

    I want to know that why this happens?

  • Hi Sai,

    Can you provide us current waveform when you see motor is stopped. I am guessing either over current or over temperature issue. If you see device starts again 300mS. It is one of those two issues.