# Need Help - 3 speed motor, 3 position switch



## jmx66 (Jul 6, 2017)

I'm having some kind of mental block...
For my homemade wiper motor mill power feed, the motor (12V DC) that has three terminals.
I'm going to run power to it from a PWM controller with a reverse switch (this thing: )





Here's the behavior:





I can't figure out how to wire the switch, assuming I need a 6 terminal DPDT?

Also does it say anything that it draws less current going CW vs CCW?

Thanks in advance!
-John


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## jim18655 (Jul 6, 2017)

Is the chart for the wiper motor? If the controller does the reversing in the output you would only need to connect two wires to the motor. Just pick what speed you want and connect. Info on the control would be helpful.


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## jmx66 (Jul 6, 2017)

Hi Jim,
Thanks.
The chart is just one I made up based on my observations.
Obviously I'm only concerned with one set i.e. the top three rows. I just included the reverse polarity because I thought it was curious that the draw and speeds were different.

It's this controller: https://smile.amazon.com/gp/product/B01NBOMR2N/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1

I want all three ranges so I need to connect three combinations via a three position switch. The speed control will do the reversing.


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## Silverbullet (Jul 7, 2017)

Your trying use the three speeds of the motor with the variable speed pot in the controller? You don't need the three speeds , just pick one and the potentiometer will vari it down or up. If you wanted you could use the high speed wire to a momentary push button switch to give you rapid travel , but you may need a relay to let it jump past.


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## jmx66 (Jul 7, 2017)

Silverbullet said:


> Your trying use the three speeds of the motor with the variable speed pot in the controller? You don't need the three speeds , just pick one and the potentiometer will vari it down or up. If you wanted you could use the high speed wire to a momentary push button switch to give you rapid travel , but you may need a relay to let it jump past.


What's wrong with having three speeds? Aren't three better than two?
It occurred to me to have a momentary that went high speed (like the "jack rabbit" button on the Grizzly) but this seemed like more flexibility.


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## gregc (Jul 7, 2017)

I am confused on what you are trying to accomplish.  The motor draws 30W max but you are using a pwm modulator rated for 3000w ?  I would also assume you would prefer to run it on 120vac so you could just plug into the wall vs having a 13v source with a battery or another power supply   Maybe just something like this. https://www.google.com/search?clien...1.64.mobile-gws-serp..0.1.216...0.0oQ7yMXNSSE


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## gregc (Jul 7, 2017)

Looks like it's cheaper to just use one switch for all desired combinations.  3 forward speeds 3 reverse speeds and 1 off position 
https://www.google.com/search?clien...64.mobile-gws-serp..1.1.87...0j41.vpTI0KCrpbI



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## Silverbullet (Jul 7, 2017)

jmx66 said:


> What's wrong with having three speeds? Aren't three better than two?
> It occurred to me to have a momentary that went high speed (like the "jack rabbit" button on the Grizzly) but this seemed like more flexibility.


Why do you need three when it's variable from 0 to  max.


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## jmx66 (Jul 7, 2017)

OK, I see what you guys are talking about. There's really not much difference if I run it on the high speed terminals (1&2) and set the pot at 5% compared to low speed at (terminals 2 &3), at say 20%. It's not like it's changing physical gears...
But there is finer adjustment between steps obviously.
So I think I will change the design so that it normally operates at the slow speed but has a momentary that goes to high speed such as when moving the table without cutting.

I have a 12amp DC power supply for this (yeah, overkill but I already have it):


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## jim18655 (Jul 7, 2017)

Single pole double throw DC rated switch. Center off would be best choice. Momentary contact in one direction better yet. One power wire to the common terminal and low to one output and high to the other output terminal. Are you still doing variable speed? If so, then you'll need a different power supply to do the high speed since your variable supply will control speed. If you're using for table feed you'll want the variable speed control.
Brush offset in the motor probably causes the difference in amps forward and reverse.
Don't forget limit switches at the end of travel.


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## jmx66 (Jul 7, 2017)

Thanks Jim. Yes, the controller has variable speed and forward/reverse. I don't understand why I need a different power supply.
I'm off to the electronics store to look for switches.


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## jim18655 (Jul 7, 2017)

If the controller is set for a slow feed speed and you want fast you would have to either turn up the speed control or switch the motor leads to the high speed. Even then the speed pot would limit the high speed.
I have a brother in your area. He's in Sausalito. Nice area!


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## jmx66 (Jul 7, 2017)

Got it. Thanks for all your and everyone's help.
Yeah, it's not a bad place to live if you can deal with the traffic and cost of living.


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