Brush gobbler

[Ryan Wright]

What would cause my generator (12.5kw Yanmar powered Kohler) to eat
through brushes at a rapid rate?

Some time after buying my coach last year, the generator quit working.
I found the rear brush to be worn all the way down and the wire popped
off. The front brush looked OK, but I replaced them both anyway, as
well as the little holder for them just for kicks. Fast forward to
this weekend: With only ~30 hours of operation on the new brushes, the
generator stopped and I found the rear brush worn down with it's wire
popped off again. Front brush still looks new. Thankfully, I still had
the good front brush from before, so I installed it in place of the
worn rear brush. This was Saturday morning.

Roughly 5 additional hours of runtime later, the generator stopped
again. That was this morning and I haven't climbed under there yet but
I suspect I'll find that rear brush worn back down.

What's the deal here?

-Ryan
'86 PT-40 8V92

[thomas_sorrentino]

Ryan,
I am going thru the exact same thing right now(yanmar/kohler). What I
discovered is that the rear commutator slip ring has a grove worn
into it, but only about a third of the way around. Causing the ring
to be more egg shaped. Which I think is whats causing that brush to
wear out so rapidily. I have no idea what has caused this irregular
wear pattern. I bought new slip rings and rear bearing, but don't
have enough guts to attempt the R+R yet! If anybody has been thru
this I also would appreciate any tips and advice.

Tom Sorrentino
1987 PT38
Bedford Hills, NY


--- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
wrote:
>
> What would cause my generator (12.5kw Yanmar powered Kohler) to eat
> through brushes at a rapid rate?
>
> Some time after buying my coach last year, the generator quit
working.
> I found the rear brush to be worn all the way down and the wire
popped
> off. The front brush looked OK, but I replaced them both anyway, as
> well as the little holder for them just for kicks. Fast forward to
> this weekend: With only ~30 hours of operation on the new brushes,
the
> generator stopped and I found the rear brush worn down with it's
wire
> popped off again. Front brush still looks new. Thankfully, I still
had
> the good front brush from before, so I installed it in place of the
> worn rear brush. This was Saturday morning.
>
> Roughly 5 additional hours of runtime later, the generator stopped
> again. That was this morning and I haven't climbed under there yet
but
> I suspect I'll find that rear brush worn back down.
>
> What's the deal here?
>
> -Ryan
> '86 PT-40 8V92
>

[Scott Forman]

Your commutator ring is worn. I went through this in January. You
have three options:

1) Replace entire genset
2) Find a modern head unit that mates up to your engine
3) Rebuild the head unit

I went for option three, as it had the lowest price and fewest
potential headaches. Now it is basically a brand new "old
technology" generator which should last another 20 years just like
the first one did.

The commutator ring must be pressed out, so machine tools are
required.

Good luck

Scott Forman
86 PT38
Memphis





--- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
wrote:
>
> What would cause my generator (12.5kw Yanmar powered Kohler) to eat
> through brushes at a rapid rate?
>
> Some time after buying my coach last year, the generator quit
working.
> I found the rear brush to be worn all the way down and the wire
popped
> off. The front brush looked OK, but I replaced them both anyway, as
> well as the little holder for them just for kicks. Fast forward to
> this weekend: With only ~30 hours of operation on the new brushes,
the
> generator stopped and I found the rear brush worn down with it's
wire
> popped off again. Front brush still looks new. Thankfully, I still
had
> the good front brush from before, so I installed it in place of the
> worn rear brush. This was Saturday morning.
>
> Roughly 5 additional hours of runtime later, the generator stopped
> again. That was this morning and I haven't climbed under there yet
but
> I suspect I'll find that rear brush worn back down.
>
> What's the deal here?
>
> -Ryan
> '86 PT-40 8V92
>

[PM7088@...]

MANY years ago I worked with large A/C.D/C motor generator set. We used to turn
the commutator with special tooling while in place. Maybe some one who rebuilds
commercial/industrial motors can lead you in the right direction. These units
are almost timeless...

Pete


-------------- Original message ----------------------
From: "Scott Forman" <sforman@...>
> Your commutator ring is worn. I went through this in January. You
> have three options:
>
> 1) Replace entire genset
> 2) Find a modern head unit that mates up to your engine
> 3) Rebuild the head unit
>
> I went for option three, as it had the lowest price and fewest
> potential headaches. Now it is basically a brand new "old
> technology" generator which should last another 20 years just like
> the first one did.
>
> The commutator ring must be pressed out, so machine tools are
> required.
>
> Good luck
>
> Scott Forman
> 86 PT38
> Memphis
>
>
>
>
>
> --- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
> wrote:
> >
> > What would cause my generator (12.5kw Yanmar powered Kohler) to eat
> > through brushes at a rapid rate?
> >
> > Some time after buying my coach last year, the generator quit
> working.
> > I found the rear brush to be worn all the way down and the wire
> popped
> > off. The front brush looked OK, but I replaced them both anyway, as
> > well as the little holder for them just for kicks. Fast forward to
> > this weekend: With only ~30 hours of operation on the new brushes,
> the
> > generator stopped and I found the rear brush worn down with it's
> wire
> > popped off again. Front brush still looks new. Thankfully, I still
> had
> > the good front brush from before, so I installed it in place of the
> > worn rear brush. This was Saturday morning.
> >
> > Roughly 5 additional hours of runtime later, the generator stopped
> > again. That was this morning and I haven't climbed under there yet
> but
> > I suspect I'll find that rear brush worn back down.
> >
> > What's the deal here?
> >
> > -Ryan
> > '86 PT-40 8V92
> >
>
>
>

[Gregory OConnor]

I think the shaft is tapered to the engine?? so it then could be the
bearing in the gen or the mounting bolts that hold the gen to the
engine?? MikeH pointed out some time ago that it is important to
replace critical bolts to get them back to spec torque.

I have a coleman light tower that had a crack in the casting that
holds the genset bearing. once I welded the crack I then started to
run thru brushes . I guess I off centered the bearing seat. when I
pulled the genhead off the Kubota I noticed a broken motor mount on
the engine side which must have cantilivered stress on the duo and
caused the crack. Servicing mounting points may also help with
vibration. vibration is more annoying than noise.

On the topic of mounting and vibration; BB has some funky exhaust
mating systems for genset slides. I notice most vibration come into
the coach from the muffler mounting.

GregoryO'Connor
94ptRomolandCa

--- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
wrote:
>
> What would cause my generator (12.5kw Yanmar powered Kohler) to eat
> through brushes at a rapid rate?
>
> Some time after buying my coach last year, the generator quit
working.
> I found the rear brush to be worn all the way down and the wire
popped
> off. The front brush looked OK, but I replaced them both anyway, as
> well as the little holder for them just for kicks. Fast forward to
> this weekend: With only ~30 hours of operation on the new brushes,
the
> generator stopped and I found the rear brush worn down with it's
wire
> popped off again. Front brush still looks new. Thankfully, I still
had
> the good front brush from before, so I installed it in place of the
> worn rear brush. This was Saturday morning.
>
> Roughly 5 additional hours of runtime later, the generator stopped
> again. That was this morning and I haven't climbed under there yet
but
> I suspect I'll find that rear brush worn back down.
>
> What's the deal here?
>
> -Ryan
> '86 PT-40 8V92
>

[Ryan Wright]

Scott, did you do this work yourself? If not, would you might sharing
a rough dollar figure as to what I should expect when I start calling
generator repair shops?

-Ryan

On Mon, Jun 2, 2008 at 5:01 AM, Scott Forman <sforman@...> wrote:
>
> I went for option three, as it had the lowest price and fewest
> potential headaches. Now it is basically a brand new "old
> technology" generator which should last another 20 years just like
> the first one did.
>

[Scott Forman]

No, I am pretty handy but this level of work is beyond my capability
right from the beginning...I have no way to get the Genset out of the
coach.

I am a bad example for costs, because the shop that services my coach
is owned by a close friend...he gives me parts at cost and greatly
reduced labor rates. That being said, it was 16 hours of labor and
$136 (at cost) in parts. You should be able to estimate your cost
based on your local hourly shop rates since the parts are insignificant.

This is the narrative from my shop invoice:
Complaint: Generator not making electricity. Cause: Exciter ring and
brushes bad. Correction: Drained coolant and disconnected radiator
hoses. Disconnected A/C wires and control box. Removed gen set from
coach. Removed engine from cradle. Dissassembled generator. Removed
armature from engine. Removed end bearing. Replaced exciter ring.
Installed new end bearing. Installed armature on engine. Assembled
generator. Put engine in cradle and installed in coach. Connected
wires, fuel lines, and rad hoses. Filled cooling system and bled air.
Cranked engine, okay. 120v A/C from both lugs at no load. Put load on
generator and let run to check out, okay.

Hope this helps
Scott

--- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
wrote:
>
> Scott, did you do this work yourself? If not, would you might sharing
> a rough dollar figure as to what I should expect when I start calling
> generator repair shops?
>
> -Ryan
>
> On Mon, Jun 2, 2008 at 5:01 AM, Scott Forman <sforman@...> wrote:
> >
> > I went for option three, as it had the lowest price and fewest
> > potential headaches. Now it is basically a brand new "old
> > technology" generator which should last another 20 years just like
> > the first one did.
> >
>

[Gardner Yeaw]

All I would ask is that if anyone does this repair, take lots of
pictures. It sounds like a pretty common problem and nothing is more
helpful that pictures along with an explanation. I don't have one of
these gen sets (yet), but Ihave friends that do.

Gardner
78FC33
--- In WanderlodgeForum@yahoogroups.com, "Gregory OConnor"
wrote:
>
> I think the shaft is tapered to the engine?? so it then could be
the
> bearing in the gen or the mounting bolts that hold the gen to the
> engine?? MikeH pointed out some time ago that it is important to
> replace critical bolts to get them back to spec torque.
>
> I have a coleman light tower that had a crack in the casting that
> holds the genset bearing. once I welded the crack I then started
to
> run thru brushes . I guess I off centered the bearing seat. when I
> pulled the genhead off the Kubota I noticed a broken motor mount
on
> the engine side which must have cantilivered stress on the duo and
> caused the crack. Servicing mounting points may also help with
> vibration. vibration is more annoying than noise.
>
> On the topic of mounting and vibration; BB has some funky exhaust
> mating systems for genset slides. I notice most vibration come
into
> the coach from the muffler mounting.
>
> GregoryO'Connor
> 94ptRomolandCa
>
> --- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
> wrote:
> >
> > What would cause my generator (12.5kw Yanmar powered Kohler) to
eat
> > through brushes at a rapid rate?
> >
> > Some time after buying my coach last year, the generator quit
> working.
> > I found the rear brush to be worn all the way down and the wire
> popped
> > off. The front brush looked OK, but I replaced them both anyway,
as
> > well as the little holder for them just for kicks. Fast forward
to
> > this weekend: With only ~30 hours of operation on the new
brushes,
> the
> > generator stopped and I found the rear brush worn down with it's
> wire
> > popped off again. Front brush still looks new. Thankfully, I
still
> had
> > the good front brush from before, so I installed it in place of
the
> > worn rear brush. This was Saturday morning.
> >
> > Roughly 5 additional hours of runtime later, the generator
stopped
> > again. That was this morning and I haven't climbed under there
yet
> but
> > I suspect I'll find that rear brush worn back down.
> >
> > What's the deal here?
> >
> > -Ryan
> > '86 PT-40 8V92
> >
>

[Ryan Wright]

Much appreciated, Scott. Thank you for sharing this.

-Ryan
'86 PT-40 8V92

On Mon, Jun 2, 2008 at 4:56 PM, Scott Forman <sforman@...> wrote:
>
> This is the narrative from my shop invoice:

[Gregory OConnor]

What is an exciter ring? Between the ExciterRing and the swaybar
threads "porpoising", I'm lost.

GregoryO'Connor
94ptRomolandCa


--- In WanderlodgeForum@yahoogroups.com, "Scott Forman"
<sforman@...> wrote:
>
> No, I am pretty handy but this level of work is beyond my
capability
> right from the beginning...I have no way to get the Genset out of
the
> coach.
>
> I am a bad example for costs, because the shop that services my
coach
> is owned by a close friend...he gives me parts at cost and greatly
> reduced labor rates. That being said, it was 16 hours of labor
and
> $136 (at cost) in parts. You should be able to estimate your cost
> based on your local hourly shop rates since the parts are
insignificant.
>
> This is the narrative from my shop invoice:
> Complaint: Generator not making electricity. Cause: Exciter ring
and
> brushes bad. Correction: Drained coolant and disconnected
radiator
> hoses. Disconnected A/C wires and control box. Removed gen set
from
> coach. Removed engine from cradle. Dissassembled generator.
Removed
> armature from engine. Removed end bearing. Replaced exciter
ring.
> Installed new end bearing. Installed armature on engine.
Assembled
> generator. Put engine in cradle and installed in coach.
Connected
> wires, fuel lines, and rad hoses. Filled cooling system and bled
air.
> Cranked engine, okay. 120v A/C from both lugs at no load. Put
load on
> generator and let run to check out, okay.
>
> Hope this helps
> Scott
>
> --- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
> wrote:
> >
> > Scott, did you do this work yourself? If not, would you might
sharing
> > a rough dollar figure as to what I should expect when I start
calling
> > generator repair shops?
> >
> > -Ryan
> >
> > On Mon, Jun 2, 2008 at 5:01 AM, Scott Forman <sforman@> wrote:
> > >
> > > I went for option three, as it had the lowest price and fewest
> > > potential headaches. Now it is basically a brand new "old
> > > technology" generator which should last another 20 years just
like
> > > the first one did.
> > >
> >
>