Motor for electric leaf blower

[Andy K]

My leaf blower stopped working.

I tested the switch and it was fine.

Power is getting to the motor.

There was a black buildup on the armature, so I sanded it with a 1500 grit sandpaper.

Now the motor starts but it stumbles.

Is there anything else I can do or is the motor toast?

Thanks,
Andy

[Adrian Jansen]

Respectfully suggest you buy a broom :-)

--
Regards,

Adrian Jansen adrianjansen at internode dot on dot net
Note reply address is invalid, convert address above to machine form.

[Tim Wescott]

It depends on how good it was to start with. If it were built in 1960 by
a reputable manufacturer you could have the motor rebuilt by turning down
the commutator (that's probably what you sanded) and replacing the
brushes.

If there's enough metal left on the commutator to turn it down, and the
brushes can be replaced, then yes, you can probably bring the thing back
to life.

If you think the commutator is clean and smooth enough, then make sure
that you've cleaned any conductive dust from between the commutator
segments, replace the brushes (or at least clean them up, too), and give
it a whirl.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

[Andy K]

Thanks.

The brushes weren't worn that much but I will clean them up.

I have replaced brushes on alternators, but this motor has a much faster r.p.m. so it stands to reason that it is gonna wear down much faster.

Andy

[Andy K]

Respectfully ignored as poor advice.

[Jon Elson]

Andy K wrote:

> My leaf blower stopped working.
>
> I tested the switch and it was fine.
>
> Power is getting to the motor.
>
> There was a black buildup on the armature, so I sanded it with a 1500 grit
> sandpaper.
>
> Now the motor starts but it stumbles.
>

Are there burned, microscopically melted spots at the edge of one of
the commutator bars? That is a strong sign of a shorted
armature winding.

Jon

[Andy K]

Thanks for your help.

Not that I can see with the unaided eye.

I checked the brushes, and the end is very slightly grooved like it wasn't making a good contact.

Others I have seen are shiny on the end.

Should I polish the end and retry it ?

The motor is only a couple years old.

I will take a picture and get back.

Andy

[Jasen Betts]

On 2013-03-19, Andy K <andrew_...@yahoo.com> wrote:

> Power is getting to the motor.
>
> There was a black buildup on the armature, so I sanded it with a 1500 grit sandpaper.
>
> Now the motor starts but it stumbles.
>
> Is there anything else I can do or is the motor toast?

clean between the commutator sectors
replace the brushes.


--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---

[Andy K]

On Thursday, March 21, 2013 1:01:34 AM UTC-5, Jasen Betts wrote:
> On 2013-03-19, Andy K <andrew_...@yahoo.com> wrote:
>
>
>
> > Power is getting to the motor.
>
> >
>
> > There was a black buildup on the armature, so I sanded it with a 1500 grit sandpaper.
>
> >
>
> > Now the motor starts but it stumbles.
>
> >
>
> > Is there anything else I can do or is the motor toast?
>
>
>
> clean between the commutator sectors
>
> replace the brushes.
>
>
>
>
>
> --
>

> ?? 100% natural

>
>
>
> --- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---

There are 2 pictures here.

http://s1127.photobucket.com/user/bicycle77017/media/Motor1_zps0b0fc792.jpg.html?sort=3&o=0

[P E Schoen]

"Andy K" wrote in message
news:5cdac662-244d-401b...@googlegroups.com...

> There are 2 pictures here.

> http://s1127.photobucket.com/user/bicycle77017/media/Motor1_zps0b0fc792.jpg.html?sort=3&o=0

Try an ohmmeter on the brushes and rotate the shaft. It should alternate
between two values depending on the position if the brushes are aligned on
one pair of windings or two. Even better would be to apply a safe, low AC
voltage (6-12 VAC) and check the current draw. A shorted winding will draw a
lot more current. You may even be able to feel some torque on the shaft or
it may try to run slowly, and you may see where it hesitates.

Or you can grab an obstructionist Republican politician by the feet and he
will blow away the leaves with hot air :)

Paul

[Andy K]

You may have found something.

Ohmmeter is showing 0 ohms no matter what position the commutator is at.

What does than mean ?

Andy

[dca...@krl.org]

On Mar 22, 12:48 pm, Andy K <andrew_kenne...@yahoo.com> wrote:
> On Thursday, March 21, 2013 10:30:58 PM UTC-5, P E Schoen wrote:
> > "Andy K"  wrote in message
>
> >news:5cdac662-244d-401b...@googlegroups.com...
>
> > > There are 2 pictures here.
>

> > >http://s1127.photobucket.com/user/bicycle77017/media/Motor1_zps0b0fc7...

>
> > Try an ohmmeter on the brushes and rotate the shaft. It should alternate
>
> > between two values depending on the position if the brushes are aligned on
>
> > one pair of windings or two. Even better would be to apply a safe, low AC
>
> > voltage (6-12 VAC) and check the current draw. A shorted winding will draw a
>
> > lot more current. You may even be able to feel some torque on the shaft or
>
> > it may try to run slowly, and you may see where it hesitates.
>
> > Or you can grab an obstructionist Republican politician by the feet and he
>
> > will blow away the leaves with hot air :)
>
> > Paul
>
> You may have found something.
>
> Ohmmeter is showing 0 ohms no matter what position the commutator is at.
>
> What does than mean ?
>
> Andy

Brushes worn down so much they do not make contact?

Dan

[Tim Wescott]

Zero ohms indicates a short circuit, not open.

In this case, zero ohms most likely indicates that the resistance of the
armature is lower than what the meter is capable of registering. The
12VAC idea sounds like a good one.

[Jamie]

dose not mean much actually.

If that is a low voltage motor, something less than 50volts, your meter
most likely won't read anything useable because the normal readings for
that motor will most likely be less than an ohm and lots of meters
just won't display any usable data down there. That is, DMM's that cost
less than 100 bucks.

What you should be doing is measure for leakage to ground/core. Any
reading less than 500k ohms is suspect. If you have a mega meter that
could be useful, too.

Also, if it has a PM (permanent magnets)? They maybe weak from heat
and that is going to cause lots of amps and no torque, but it'll spin like
hell if you can get it running. Once the magnets start degrading for
what ever reason, the heat from efficiency loss just exponentially
degrades the motor.

I am guessing you may have a series motor. Those motors are only
limited in RPM's with respect to the load on them. I've seen those short
a few turns of wire with out showing any ground shorts. You should take
note the color of the magnetic wire if you can see it. It should not
look like it has been subjected to heat! When this happens to these
types of motors, you'll see more brush arcing than normal, even with
a clean commutator and new brushes.

Have a good day..

Jamie

[dca...@krl.org]

On Mar 22, 1:18 pm, Tim Wescott <t...@seemywebsite.com> wrote:


> >> You may have found something.
>
> >> Ohmmeter is showing 0 ohms no matter what position the commutator is
> >> at.
>
> >> What does than mean ?
>
> >> Andy
>
> > Brushes  worn down so much they do not make contact?
>
> Zero ohms indicates a short circuit, not open.
>

> Tim Wescott, Communications, Control, Circuits & Softwarehttp://www.wescottdesign.com

You are absolutely right. Zero ohms does indicate a short. But in
the original post Andy said the motor did not run and the switch was
good. So I assumed when he said Zero Ohms, he really meant the meter
did not indicate anything and he really had a open. Not likely to be
a dead short and not have a lot of excitement with 120 volts applied.
Of course he may have a battery operated leaf blower................
Or he has it plugged into a dead outlet.


Dan

[P E Schoen]

dcaster wrote in message
news:8076dd06-edc6-48dd...@e16g2000yqj.googlegroups.com...

> You are absolutely right. Zero ohms does indicate a short. But in
> the original post Andy said the motor did not run and the switch was
> good. So I assumed when he said Zero Ohms, he really meant the meter
> did not indicate anything and he really had a open. Not likely to be
> a dead short and not have a lot of excitement with 120 volts applied.
> Of course he may have a battery operated leaf blower................
> Or he has it plugged into a dead outlet.

He said in a later followup:

> > Now the motor starts but it stumbles.

That's why I suspected a bad winding or connection to a commutator section.

The proper way to test this motor is with a "growler":
http://en.wikipedia.org/wiki/Growler_(electrical_device)

Here's a video of one being used on a 110V reel motor armaturer:

http://www.youtube.com/watch?v=yXQ0heuV6VE

Paul

Paul

[P E Schoen]

Some other educational videos, one on testing:

http://www.youtube.com/watch?v=P8_faVUO7Do

and one on repair:

http://www.youtube.com/watch?v=Fb2IMdlKBiw

Paul

[Andy K]

It been interesting gentlemen.

Looks like Toro doesn't want their products repairable by the consumer.

Minimum order for a replacement motor is 500.(Mamco motor)

I think the armature is shorted out.

Andy

[dca...@krl.org]

On Mar 24, 9:17 am, Andy K <andrew_kenne...@yahoo.com> wrote:

> Looks like Toro doesn't want their products repairable by the consumer.
>
> Minimum order for a replacement motor is 500.(Mamco motor)
>
> I think the armature is shorted out.
>
> Andy

Check your Salvation Army store and the Goodwill. I bought a Sears
leaf blower motor for $ 4. Did not include all the parts as nozzles
and tubing.


Dan

[Andy K]

I fixed it.

Those ridges in the brushes weren't normal.

After sanding them smooth, the leaf blower is against producing 180 m.p.h. winds.

I think the brushes are made of graphite.

Andy

[josephkk]

On Thu, 21 Mar 2013 23:30:58 -0400, "P E Schoen" <pa...@peschoen.com>
wrote:

Republicans produce almost adequate amounts of hot air, but for really
serious wind you need a Democrat. The only problem is that generate so
much hot air that they are hard to control. All wild thrust and no wings
to control them.

?-)

[mrda...@gmail.com]

Impressive! I will have to keep this in mind.

By the way, these kinds of AC motors also function nicely with about 24V DC. (Yes, DC.)

Michael

[Jamie]

Is it any wonder why they call them universal motors?


Jamie

[Robert Neill]

Hi there, looks like motor has commutator and brushes from your reply (assume universal series wound motor). Commutator segments may need undercutting as was common with automotive dynamo's. The Haynes Automotive Electrical systems service manual mentions an undercutting tool and in the starter motor chapter, a
growler tool is mentioned which checks the armature winding insulation by electromaganetic induction.