Make It Go Backwards!

[Ron Hubbard]

I was doing some carpentry work in my bedroom with a belt sander and
in one careless moment, I put the tool down on a blanket as the motor
was winding down. Less than 30 seconds later, part of the blanket has
gotten caught up in the gears.

It's been a long while since I've built a motor controller. Does
anyone know of a circuit-- preferably a really simple one-- for
reversing an AC motor? I hate to have to buy a new sander, and I miss
my blanky... <g>

Ron

 

[Jasen Betts]

On 2010-02-20, Ron Hubbard <ryon@dslnorthwest.net> wrote:

I was doing some carpentry work in my bedroom with a belt sander and
in one careless moment, I put the tool down on a blanket as the motor
was winding down. Less than 30 seconds later, part of the blanket has
gotten caught up in the gears.

It's been a long while since I've built a motor controller. Does
anyone know of a circuit-- preferably a really simple one-- for
reversing an AC motor? I hate to have to buy a new sander, and I miss
my blanky... <g

open up the motor and swap the connections to the brushes.

If the terminals to do that aren't provided externally it
can't be done from outside the motor.


www.howeverythingworks.org/supplements/electric_motors.pdf
unbiversal motors paragraph 3.

reversing the brushes has the exact (opposite) effect of reversing the stator
wiring, (and so has the same result) but is generally easier to do


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[Ron Hubbard]

Jasen Betts wrote:

On 2010-02-20, Ron Hubbard <ryon@dslnorthwest.net> wrote:
I was doing some carpentry work in my bedroom with a belt sander and
in one careless moment, I put the tool down on a blanket as the motor
was winding down. Less than 30 seconds later, part of the blanket has
gotten caught up in the gears.

It's been a long while since I've built a motor controller. Does
anyone know of a circuit-- preferably a really simple one-- for
reversing an AC motor? I hate to have to buy a new sander, and I miss
my blanky... <g

open up the motor and swap the connections to the brushes.

If the terminals to do that aren't provided externally it
can't be done from outside the motor.


www.howeverythingworks.org/supplements/electric_motors.pdf
unbiversal motors paragraph 3.

reversing the brushes has the exact (opposite) effect of reversing the stator
wiring, (and so has the same result) but is generally easier to do.

Hey, great. This info is much appreciated! Now if I can only get it
open... what did I do with that hammer and chisel, hmm? <g>

Ron

 

[Jasen Betts]

On 2010-02-21, Ron Hubbard <ryon@dslnorthwest.net> wrote:

Jasen Betts wrote:
On 2010-02-20, Ron Hubbard <ryon@dslnorthwest.net> wrote:
I was doing some carpentry work in my bedroom with a belt sander and
in one careless moment, I put the tool down on a blanket as the motor
was winding down. Less than 30 seconds later, part of the blanket has
gotten caught up in the gears.

It's been a long while since I've built a motor controller. Does
anyone know of a circuit-- preferably a really simple one-- for
reversing an AC motor? I hate to have to buy a new sander, and I miss
my blanky... <g

open up the motor and swap the connections to the brushes.

If the terminals to do that aren't provided externally it
can't be done from outside the motor.


www.howeverythingworks.org/supplements/electric_motors.pdf
unbiversal motors paragraph 3.

reversing the brushes has the exact (opposite) effect of reversing the stator
wiring, (and so has the same result) but is generally easier to do.

Hey, great. This info is much appreciated! Now if I can only get it
open... what did I do with that hammer and chisel, hmm? <g

if it were my sander I'd be looking for a way to dissasemble it
unless the brushes can be accessed without dissasembly (some tools
provide ports for replaceing the brushes without opening the "shell"
but even then rigging it with the wires crossed could be a little tricky

another option may be finding a hole you can insert a probe into to
push the rotor round, and winding it back by hand.



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[Ron Hubbard]

Jasen Betts wrote:

On 2010-02-21, Ron Hubbard <ryon@dslnorthwest.net> wrote:


Jasen Betts wrote:
On 2010-02-20, Ron Hubbard <ryon@dslnorthwest.net> wrote:
I was doing some carpentry work in my bedroom with a belt sander and
in one careless moment, I put the tool down on a blanket as the motor
was winding down. Less than 30 seconds later, part of the blanket has
gotten caught up in the gears.

It's been a long while since I've built a motor controller. Does
anyone know of a circuit-- preferably a really simple one-- for
reversing an AC motor? I hate to have to buy a new sander, and I miss
my blanky... <g

open up the motor and swap the connections to the brushes.

If the terminals to do that aren't provided externally it
can't be done from outside the motor.


www.howeverythingworks.org/supplements/electric_motors.pdf
unbiversal motors paragraph 3.

reversing the brushes has the exact (opposite) effect of reversing the stator
wiring, (and so has the same result) but is generally easier to do.

Hey, great. This info is much appreciated! Now if I can only get it
open... what did I do with that hammer and chisel, hmm? <g

if it were my sander I'd be looking for a way to dissasemble it
unless the brushes can be accessed without dissasembly (some tools
provide ports for replaceing the brushes without opening the "shell"
but even then rigging it with the wires crossed could be a little tricky

another option may be finding a hole you can insert a probe into to
push the rotor round, and winding it back by hand.

I was just joking-- mostly. Ryobi is a very under-rated company. They
make very rugged tools and it took me nearly an hour to find all of
the screws (hidden and otherwise) holding the sander together. But
once done, it didn't take very long to fix the problem although re-
assembly was a little trickier as some of the screws are shorter than
others, going into specific places rather than a single size screw
that can go in anywhere.

Ron