Snowblower Electric Chute motor Limits

[56servi 28]

I added a 12v motor to my tall chute snowblower on my 520. Used the same setup as THEROUNDHOUSERNR posted on Dec 30, 2013.  Works great except when I run past the chute teeth when turning left or right.  I am using a momentary DPDT switch for a wench to turn.  I thought I could stop it by watching when it was at the end of the teeth, but I can't see the teeth when ib the cab.  When it goes past the teeth it pushes the gear away and then won't turn until I get out and push the gear back into the teeth.

My thought is to use 2 roller limit switches.  One for each direction.  Run the wires from the DPDT switch to the limit switches, one to each switch.

The DPDT changes the motor direction by switching + & - to the motor.

Using a normally closed limit switch would open one of the 2 switches when a limit is reached.  Depending on direction the + or - side would be opened stopping the motor.

 

 

[R Scheer 502]

Only problem I see is when you hit the limit switch you've killed power to the motor.  You would have to manually rotate the chute until the limit switch closes again.  I would look at doing a latching relay.  When the cw limit switch picks up it sets the latching relay to run the motor ccw.  Similar for the ccw limit switch, it would toggle the motor to run cw.  This way when you hit the limit switch the chute would start turning in the opposite direction automatically.  You could wire a momentary toggle switch to operate the latching relay so you can select direction from you dashboard.  You'd need a spst toggle switch as well for on off.

 

Just thoughts.

[56servi 28]

I knew this idea was too easy to work

Thanks for pointing that out

[wallfish 16,985]

Two of those limit switches will work because it will only cut power in the direction the chute is turning. Power to turn it in the other direction still exists when set up properly. Only issue may be the switches, so they will need to be protected from weather and snow and also whatever is triggering the switches.

My 2 stage uses basically the same setup you have but it uses a power window motor. I can easily see the chute and gears but would prefer an easier method. The motor isn't as strong as yours so it will stop when it binds.  I was think'n of grinding in new teeth all the way around the chute so it can spin 360. Another idea is to go with a sprocket on the motor and a roller chain to eliminate that worm gear drive. Teeth would still have to be ground into the chute or add a sprocket to the chute. Just so happens #35 bicycle chain fits pretty good into the existing teeth on the chute. I picked up a 2 piece aluminum sprocket to fit the chute but haven't got to doing anything with it yet. 

If you can find a thread done by Wheelbearing, he did an excellent mod to his chute with a chain. It was a 2 stage but still the same basic principles apply

[R Scheer 502]

Wallfish

 

Could you elaborate on how you would still have power to the motor when the limit switch is reached?  I'm just not seeing it based on the 56servi schematic.  Not trying to argue, just want to learn.

 

Now maybe if  diode was added to the between the NO connection and COMMON on the limit switch...

 

This would stop the motor when the limit is reached but still allow it to turn back.  Just have to make sure the diode has the current rating, and make sure it's pointing the right direction.

 

[wallfish 16,985]

Based on his schematic it won't work but wiring it correctly with the limit switches it will work. Concerns with it working wasn't really based on his drawing but I probably should have explained it better.

By connecting the limit switches at the X part he has on his drawing of the dual pole switch it will only cut the connection to the motor to one side at a time. The switches need to be wired in before the cross over to the reversible direction motor connections. The dual switch only feeds power to the side it's thrown to, so the other side is always temporarily dead until the switch is thrown to that side. Reversing the polarity is what reverses the motor so that's why you see both + and - to both sides of the motor. 

 

I don't know what the symbol is for a limit switch in schematics but hopefully this crude drawing will help. Not to scale and the real locations for limit switches and the triggers will need to be set up properly

 

 

 

 

[R Scheer 502]

Thanks for clearing up my confusion.  

[wallfish 16,985]

No problem. I should have explained the rewire to the limit switches.

Another idea is to relocate the electric motor to turn the chute from the top center line. My Toro walk behind controls the chute like that but with a lever and gears vs an electric motor. With the motor shaft connected to the chute on top and on the center line, it can rotate it without restriction of the worm gear teeth. It's too late to get pics of the Toro but I will tomorrow. Here's the basic idea with another crude drawing.

 

 

 

[bc.gold 3,403]

The snow thrower on my Simplicity 9020 had a simple set up for the electric chute, a gear drive motor was attached to the end of the capstan. Several wraps of cable did the work.

 

The chute sat on  three of the grooved bearings, no relays or limit switches were used on this system the DC current was handled by a D.P.D.T. switch.

 

Since the wind coming onto our property is predominantly from the north, I have the chute in a fixed position blowing the snow in a southward direction.

 

 

 

Edited February 9, 2020 by bcgold

[peter lena 8,583]

56servi, in addition to the detailing of your chute rotation, you should detail every rotational movement /frictional point, i even cut out a Teflon base gasket for my chute to blower housing , i use chain and cable lube at every movement point , making my chute work with total ease.  kill off a rusty drag / contact point with lubrication  ,and enhance the movement , pete 

[CCW 1,292]

Would physical stops on the chute preventing it from passing the end of the gear work?  Avoid all the extra electronics.

Edited February 9, 2020 by CCW

[wallfish 16,985]

46 minutes ago, CCW said:

Would physical stops on the chute preventing it from passing the end of the gear work?  Avoid all the extra electronics.

It would but that motor he's using is pretty strong. The force turning the worm gear might cause it to slip and wear the teeth when reaching the mechanical limit but that's a good idea to check out. That's pretty much how mine stops now because the gears cinch and will actually stop the motor before stripping the gears.

For mine I'd like it to turn it past where it stops now.

[CCW 1,292]

Makes sense which makes an automated approach all the more important.

[pfrederi 17,672]

Or Man Up ditch the cab and use the hand crank...

[56servi 28]

I am going to use the 2 diode method that THEROUNDHAUSERNR showed in his 2013 post.  

I made a test circuit to test how it would work with junk parts I had laying around.  I used 2 LED's to sub for the motor turning CW & CCW.  The LED's only work with correct polarity so both don't come on at same time.  THe diodes I had were small power the switch was not a momentary so I had to reverse by hans and the limit switched I found in a junk box.

I need to buy the correct diodes & limit switches to put on my snowerthrower.

The series of pictures shows the LED's on with the various limit switch positions

I hope they show up correctly.

 

Thanks for all the help

Gene

[Xearl 131]

My idea is to have more teeth machined into the ring so you can rotate the shoot a little more in each direction .  I find at times I wish I could rotate the shoot just a little bit more .