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Thread: More Mule then Rover?

  1. #171

    Re: More Mule then Rover?

    Sounds like a simple way to get things going with what you have in the parts bin :-)

    Although I wonder if you couldn't just drive it all with relays, cheaper than the motor controller, if you don't need PWM...

  2. Re: More Mule then Rover?

    Although I wonder if you couldn't just drive it all with relays, cheaper than the motor controller,
    jwatte, while the 80A relays are cheap, the solid state relays needed for the arduino to control them are not, and
    I don't have a lot of them in my parts bin. because I have the sabertooth already that is the cheapest way to go.

    there's also the gearing issue, the lifting chain sprockets are #50 13 teeth @3" dia., they are on a 1" shaft with
    a drive sprocket #40 30 teeth @5" dia. , then the motor has #40 9 teeth @1.5" dia.

    the motors are 1000W 180rpm.

    I'm going to need the speed controller to get the right lifting and dumping speeds right.

  3. Re: More Mule then Rover?

    I was thinking of using this SPST 300A 24Vdc relay for the Drive enable relay.
    It was listed as continuous duty, but still gets very hot after prolonged use.
    and it draws .5amps

    Click image for larger version. 

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    this is the new remote controller enclosure(I think)

    Click image for larger version. 

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    Last edited by Tommy_T; 3 Weeks Ago at 06:11 PM.

  4. #174
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    Re: More Mule then Rover?

    How hot is hot? What is the maximum running current of the entire drive system?
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh

  5. Re: More Mule then Rover?

    How hot is hot?
    tician, too hot to touch, that was with no load.

    Just relay connected to 24vdc battery over night.
    Last edited by Tommy_T; 3 Weeks Ago at 10:16 PM.

  6. Re: More Mule then Rover?

    two of these in series should give me a warm&fuzzy for a Drive enable relay(s).

    Click image for larger version. 

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    two of them should draw .400 Amps (coil listed as 60 ohm)
    Last edited by Tommy_T; 3 Weeks Ago at 06:26 AM.

  7. Re: More Mule then Rover?

    baby steps.
    which sucks because we got 6" of snow on way.

    Click image for larger version. 

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  8. #178
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    Re: More Mule then Rover?

    Quote Originally Posted by Tommy_T View Post
    two of these in series should give me a warm&fuzzy for a Drive enable relay(s).

    two of them should draw .400 Amps (coil listed as 60 ohm)
    Two 60 Ohm coils in series would be 120 Ohm. 24V / 120 Ohm == 0.2A and ~4.8W of power (most of it as heat once the relay has been closed). 2.4W in a small plastic package might not be much of an improvement compared to 12W in a heavy metal enclosure that is supposed to be bolted to a metal chassis (heat sink).
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh

  9. #179

    Re: More Mule then Rover?

    Cost saving tip: You can drive the coils of the 80A relays with a simple MOSFET from the Arduino!

    The BS170 turns on at about 2V gate voltage, and is good up to 500 mA coil current depending on specific package/cooling. You could also use a much higher rated MOSFET with logic level gate, like AOTF2618L or whatever.

    Anyway, if you need speed control, then relays are out anyway. Just thought I'd mention this easy way to do it, in case this threads shows up on Google sometime.

    Click image for larger version. 

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  10. Re: More Mule then Rover?

    Two 60 Ohm coils in series would be 120 Ohm.
    tician, my bad. I'm going to be running the load output contacts in series.
    that way if the contacts stick on one of relays the other can still drop the drive voltage
    in case of emergency.

    my drive power fuse is 100A. the relay is rated as 120A, too close for a warm&fuzzy feeling
    but, two in series could.



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