Shop OBEX P1 Docs P2 Docs Learn Events
How to control a brushless motor using the prop — Parallax Forums

How to control a brushless motor using the prop

msiriwardenamsiriwardena Posts: 301
edited 2012-08-16 07:16 in Propeller 1
I require to use a brushless motor(in an oxygen rich envirnment - no sparking) - The motor I have is used in model planes- E-Flite power 32.
I plan to gear it down to slower RPM for my use.They are normally used Elecronic Speed Controlle(ESC)- which are expensive and I do not
all other functions/contrls associated with flying.Minimum to turn on/off - the motor,if I van control the RPM's is excellent.

The motor has 3 connections - Black/Red - power connections and a blue(? speed contol).
Can this be simply controoled with a potentiometer manual/electronic.or is there motor driver available to use with the prop.

Thank you.

Siri
P.S - The motor specs are attached.
pdf
pdf
EFLPower32OutrunnerInstructions.pdf
81K

Comments

  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-08-15 09:53
    Model airplane type brushless motors need electronic commutation. So, you need to feed it with 3 phase AC synchronous to the motor rotation. Really, the best way to do so is with an ESC. I've been working on a prop-based design to do so, but I'll also have a lot of extra parts since I'm going for a high power application with regenerative braking.

    If the ESC is too expensive, find a cheaper ESC. HobbyKing.com has a lot of cheap ESCs, and it's probably best you use one of those, but be sure to downgrade it since they're designed to have propeller airflow past them for the power ratings they state.

    How much power/torque do you actually need in your environment? That's a really powerful motor (about one horsepower).
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-08-15 09:56
    Also, there's a lot more detail to driving these motors. If you're not driving a propeller, then an air-flight ESC won't drive it effectively, since it just guesses what the motor does up to a certain speed, until it can get inductive feedback from the motor. If you need zero-rpm torque, then you ought to find a motor made for RC Car use, which have hall-effect sensors to help the ESC with synchronous commutation.
  • SRLMSRLM Posts: 5,045
    edited 2012-08-15 10:04
    If you don't want to use any programming, you could use a servo tester device hooked up to the ESC to control the speed via turning a knob.

    You can have a microcontroller read the speed by using: http://www.espritmodel.com/brushless-rpm-sensor-v2.aspx

    @ Circuitsoft

    You're making an ESC? This guy was making one, but he disappear. Any chance you'll make a version with four outputs for quadrotor usage?
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-08-15 10:11
    I'm making a 2xBLDC controller, but planning to drive ~60v@150A. 7HP BLDC motor for a go-kart design. Not useful for a quadrotor.
  • msiriwardenamsiriwardena Posts: 301
    edited 2012-08-15 10:22
    Circuitsoft/SLRM,
    I am at the moment is using a 1/4HP AC motor - it works well with it.I am not using oxygen at the moment - just air.I see the sparking at the brushes.
    S that is why I am trying to use a BLDC motor.
    Thanks for the Help.

    Siri
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-08-15 10:24
    What is your application? Do you need torque at low speed, or are you driving a fan?
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-08-15 11:54
    If you have a QuickStart board, you can use it as a servo tester/contoller using the touch pads to adjust end points and other parameters. Here's a link to the program with instructions.

    I agree with the suggestion to use an inexpensive ESC from HobbyKing.
  • msiriwardenamsiriwardena Posts: 301
    edited 2012-08-15 12:44
    @Circuitsoft,
    I am using the motore to drive a gas pump.It needs some torque as the pump starts and stops about every second.Notmuch pressure is involved
    only about 10cm of water.


    Thanks for your help.

    Siri
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-08-15 13:40
    You definitely want to find a motor and controller made for car use and not for airplane use, then. You can find more info by reading this and the previous guide by the same person.
  • W9GFOW9GFO Posts: 4,010
    edited 2012-08-15 14:03
    The first thing that comes to mind is that you can probably find an explosion proof DC motor. An example is marine engine compartment blowers. As low as about $30 at West Marine. I think that they are too low torque for your needs but there are surely other motors made for hazardous environments that would be suitable.

    A stepper motor might work well too, inexpensive and easy to control.
  • W9GFOW9GFO Posts: 4,010
    edited 2012-08-15 14:08
    Another option is to use a brushless motor with internal controller. I have one in my toolbox that is 12V, intended for use to power a bicycle. It only requires a potentiometer to control speed - no reverse.
  • W9GFOW9GFO Posts: 4,010
    edited 2012-08-15 14:57
    Oh, since you are pumping liquids a small submersible bilge pump can be had for about $20 and is ignition protected.

    41ocEexNLAL._SL500_AA300_.jpg

    http://www.amazon.com/Rule-24-Marine-360-GPH-12-Volt/dp/B000O8D8QG/ref=sr_1_5?s=sporting-goods&ie=UTF8&qid=1345067714&sr=1-5&keywords=bilge+pump
  • Mark_TMark_T Posts: 1,981
    edited 2012-08-15 20:22
    RC brushless motors are sensor-less so torque or control at slow speeds is not going to happen - you need a hall-effect BLDC motor and controller really.
  • msiriwardenamsiriwardena Posts: 301
    edited 2012-08-16 07:16
    @Mark_T/W9GFO/Circuitsoft

    I am very glad I pu this on the forum,I have learned a lot about BLDC/RC motors.I will continue to look for a suitable BLDC motor.
    @W9GFO - I am pumping oxygen/oxygen+air and the pump has to be small and light weight as it has to be very potable.

    I will keep all the advise in mind when searching for the BLDC motor..

    Thank you very much for all the advise.

    Siri
Sign In or Register to comment.