# A Couple Of Dc Motor Controller Switch Questions



## calstar (May 13, 2016)

1.       Can any common toggle switch be used as an inhibitor switch by connecting it to the inhibitor switch terminals  on the controller? 

2.       Can a dpdt switch be used as a forward-off-reverse switch if wired in the cord from the controller to the motor; is this the same as manually changing the leads?

thanks,

Brian


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## TOOLMASTER (May 13, 2016)

you can reverse but do it under no load...turn to 0 first


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## RCWorks (May 13, 2016)

I'm not sure what your inhibitor inhibits.

A DPDT switch is fine for reverse, gust make sure it can handle the current draw of your motor.


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## calstar (May 13, 2016)

RCWorks said:


> I'm not sure what your inhibitor inhibits.
> 
> A DPDT switch is fine for reverse, gust make sure it can handle the current draw of your motor.



My understanding is with the inhibitor open the motor will not run(then its safe to operate the dpdt), and when it closes the motor will start at the speed it was last running, accelerating at the setting of the  accel pot to the last running speed. This eliminates the the need to reset the potentiometer each time you start the motor.  This 1s all new territory for me, reading quite a bit, talking to manufacturer techs some before I purchase a motor controller and trying to figure this DC stuff out.

Brian


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## RJSakowski (May 13, 2016)

If you want forward/off/reverse from a single switch for a DC motor you will need a on/off/on switch, dpdt, center off.  Here is an example: http://www.digikey.com/product-detail/en/nkk-switches/S7ALF/360-3163-ND/4512500


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## uncle harry (May 14, 2016)

TOOLMASTER said:


> you can reverse but do it under no load...turn to 0 first



Too true. I killed a nice drive doing that very thing.

There are regenerative DC drives that can be reversed with a signal input which also gives braking capabilities.  I've applied them to control 1/2 HP DC motor drives for a large band sawmill with good success.


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## timvercoe (May 14, 2016)

If your bypassing a safety feature with a switch................just a word of caution.  Can you post some diagrams of what your doing?  If your interrupting the current to the motor with a toggle switch you've got to have a switch that will handle the current of the motor.  The DC stuff I am most familiar with is Fincor, they do large electric motors, heavy amp draws don't know of a switch that would handle the loads.  They are four wire motors.  Two field wires, two armature wires, you can change rotation by reversing the field wires or the armature wires.  Field circuits are lighter loads.  If the motor is 2 wires it would be a permanent magnet motor and you would just reverse the power and ground on the leads.  Usually the controller for the motor would have a reversing function with a control circuit.  If you wire your switch into the control circuit that would be safest but there could be a provision for that. One more little thing, Horse Power is roughly 750 watts to 1 HP.  Wattage is the function of voltage times amperage, with this knowledge you can figure out the amp draw of the armature leads.  I find my self giving a lot of advise here with out really enough information about what your doing.    Sorry for that.   Tim


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## calstar (May 14, 2016)

_"If your bypassing a safety feature with a switch........"  _

_"...you can change rotation by reversing the field wires or the armature wires. Field circuits are lighter loads."
_
Thanks Tim

Nope, not bypassing a safety feature.  Here is a vid of  the board I'll be using and an explanation of the inhibit function(which I tried to explain earlier in the thread). It looks like a typical toggle in the vid, any reason I couldn't use a decent quality toggle for it?

I plan on wiring the dpdt to the field wires, good to go? This board does not have a reversing function, boards that do seem to cost about 50-75% more. If I can safely use this method to get reversing  ability I'll do it, if not I'll get one that does.

Thanks, Brian


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## John Hasler (May 14, 2016)

You should be able to use a simple switch for the inhibit.   It would be a good idea to rig things so that the motor cannot be reversed while running.  Doing so is likely to zap the controller.  Also make sure that the motor is a type that can run both ways.  Some DC motors have angled brushes that will break if you reverse the motor.


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## mattthemuppet2 (May 14, 2016)

A simple DPDT switch will be fine as long as it has a center off. I've never tried (nor needed) to immediately reverse mine while it's still spinning forward, I've always been able to let it stop before reversing.

If you  can use one of the generic MC controllers, you can cut a resistor (RPS3) to defeat the "turn pot to 0 before starting" feature.


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## calstar (May 15, 2016)

Thanks John, the motor is reversible, last in service on a mill. And yes, all the sources I've seen say make sure there is no power before changing directions or the controller will be toast.

_" ......you can cut a resistor (RPS3) to defeat the "turn pot to 0 before starting" feature."  mattthemuppet_

It is not necessary to turn the pot to 0 when using the inhibitor switch on this Minarik controller. I don't know if I can use a generic MC,  I'll do some searching, but the Minarik is $83(generic MC $60+-?), includes a speed pot,  and given the vid tutorials I'v seen a straightforward install.

Thanks guys,

Brian


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## timvercoe (May 15, 2016)

Thanks for the feed back, it seems like you will be fine doing what your suggesting.  If it doesn't work and damages the switch or the board, you have indicated that you would purchase a board that has the reversing feature.  Assuming you already own the board in question........Tim


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## mattthemuppet2 (May 15, 2016)

calstar said:


> It is not necessary to turn the pot to 0 when using the inhibitor switch on this Minarik controller. I don't know if I can use a generic MC,  I'll do some searching, but the Minarik is $83(generic MC $60+-?), includes a speed pot,  and given the vid tutorials I'v seen a straightforward install.
> 
> Thanks guys,
> 
> Brian



ah right, sounds like a proper DC motor controller - I'd go with that over the MC type boards


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## Wireaddict (Jun 5, 2016)

From what I saw on the video the inhibit switch is simply a SPST toggle connected across the drive enable terminals.  Opening the switch only disabled the drive so the motor coasted ti a stop without dynamic braking or regeneration.  [If I were to use regeneration to stop the motor quicker I'd apply it to the field winding if the motor had one & if the drive had that option.]


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