Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
ray
 
Posts: n/a
Default re Honda 240/12 v portable generator

Hi, hoping someone can help.. I have a 3.5 kva electric start portable
petrol generator which has not been used for around 3 years.

Motor styarts and runs great, but no generation of any electrical power..

It has been suggested that one should "excite" the armature and another
mentions
polarizing the armature.....Is there someone out there that can put me on
the right track?
regards Ray (Victoria,Australia)



  #2   Report Post  
Fred McKenzie
 
Posts: n/a
Default

Motor styarts and runs great, but no generation of any electrical power..

It has been suggested that one should "excite" the armature and another
mentions
polarizing the armature.

Ray-

I assume you have checked the wiring and circuit breakers to be sure there is
no open circuit. With the motor off, the D.C. resistance measured across the
A.C. output terminals should be fairly low.

With the motor not running, you might "touch" the AC output circuit with a car
battery, or perhaps the battery used for electric start. Hopefully there would
be no more than a small spark, but at worst the circuit breaker might pop. I
would think that small amount of excitation would accomplish the polarization,
and it would take off and deliver power the next time it was started.

The next time you start it after attempting the polarization, be sure there is
a sizeable load such as an electric heater. Just a light bulb may or may not
draw enough current to build up the magnetic field.

Fred


  #3   Report Post  
James Sweet
 
Posts: n/a
Default


"ray" wrote in message
...
Hi, hoping someone can help.. I have a 3.5 kva electric start portable
petrol generator which has not been used for around 3 years.

Motor styarts and runs great, but no generation of any electrical power..

It has been suggested that one should "excite" the armature and another
mentions
polarizing the armature.....Is there someone out there that can put me on
the right track?
regards Ray (Victoria,Australia)




Have you excited it? If it sits long enough you will need to do this before
it'll work.


  #4   Report Post  
ray
 
Posts: n/a
Default

Thanks Fred & James,
Your interest & advice is much appreciated.

I did get a response from another newsgroup, which advised me to have a look
at http://www.endtimesreport.com/dead_gen.html .

It turned out to be a comprehensive article entitled "RE-ENERGIZING DEAD
GENERATORS " (2.5 pages)

In short, it suggests a way of doing it by connecting the output of a spare
generator to the output of the dead generator, while the dead generator is
being driven by the petrol engine ?? uses three 60 watt globes in series
in the connecting line. ??

I am hesitant in trying this procedure, as we are talking about 240 volts
AC.....

If you could have a look at this article and give me your opinion before I
take an action that could turn out to be a really bad thing....

regards Ray





  #5   Report Post  
Fred McKenzie
 
Posts: n/a
Default

If you could have a look at this article and give me your opinion before I
take an action that could turn out to be a really bad thing.

Ray-

Thanks for posting a link to the generator article. I printed it out, and will
add it to my generator folder.

The article has a couple of good ideas. If you do as it says, you can probably
resuscitate your generator. I would go for using household power, rather than
scrounging up a second generator.

There were a couple of comments that were not clear to me. He indicated that
the three bulbs would start flashing. Actually, flashing is the indication
that you have succeeded in polarizing your generator, and is the result of a
slight difference in frequency between your generator and the other source of
voltage. What he should have said, is that you unplug the connection between
the two voltages between flashes, when the bulbs are dark. That is the point
when both voltages are identical and in-phase, and zero current is flowing.

If you are connecting between the 120 VAC generator outlet and your household
120 VAC outlet, two series-connected 60 watt bulbs would probably be adequate.
When the generator is NOT working, the voltage will be about 120 VAC across the
bulbs. Then when the generator starts to work, maximum voltage would be 240
VAC across the bulbs, at the point where the two voltages are out of phase.

Whatever you do, be VERY CAREFUL. I would probably add a double-pole switch at
the plug to be disconnected, to disconnect power "neatly" instead of just
pulling a plug that has dangerous voltage on its exposed terminals.

Fred



  #6   Report Post  
Suraj Singh
 
Posts: n/a
Default

When I first read the article I did convinced with the idea of giving
the field excitation with an AC current. It should be DC current to
restore the residual megnetism which has lost due to not using for a
long time.

I googled and found an articles after reading this, that made a little
sence.

http://www.findarticles.com/p/articl...42/ai_55463575

you should first try with a Battery and then starting the generator
with good load. It should work.

Excitation with 120V 60 Hz AC with a bulb in series should require
only for big industrial generators.

Regards,

Suraj


"ray" wrote in message ...
Thanks Fred & James,
Your interest & advice is much appreciated.

I did get a response from another newsgroup, which advised me to have a look
at http://www.endtimesreport.com/dead_gen.html .

It turned out to be a comprehensive article entitled "RE-ENERGIZING DEAD
GENERATORS " (2.5 pages)

In short, it suggests a way of doing it by connecting the output of a spare
generator to the output of the dead generator, while the dead generator is
being driven by the petrol engine ?? uses three 60 watt globes in series
in the connecting line. ??

I am hesitant in trying this procedure, as we are talking about 240 volts
AC.....

If you could have a look at this article and give me your opinion before I
take an action that could turn out to be a really bad thing....

regards Ray

  #7   Report Post  
James Sweet
 
Posts: n/a
Default


"ray" wrote in message
...
Thanks Fred & James,
Your interest & advice is much appreciated.

I did get a response from another newsgroup, which advised me to have a

look
at http://www.endtimesreport.com/dead_gen.html .

It turned out to be a comprehensive article entitled "RE-ENERGIZING DEAD
GENERATORS " (2.5 pages)

In short, it suggests a way of doing it by connecting the output of a

spare
generator to the output of the dead generator, while the dead generator is
being driven by the petrol engine ?? uses three 60 watt globes in series
in the connecting line. ??

I am hesitant in trying this procedure, as we are talking about 240 volts
AC.....

If you could have a look at this article and give me your opinion before

I
take an action that could turn out to be a really bad thing....

regards Ray






That sounds kinda dangerous! I suggest a safer route, take a 6v lantern
battery, or some D batteries in series, a 12v gel-cell, whatever and connect
it to the output of the dead generator for a few seconds.


  #8   Report Post  
Suraj Singh
 
Posts: n/a
Default

I meant to say I did not convinced at first...

(Suraj Singh) wrote in message . com...
When I first read the article I did convinced with the idea of giving
the field excitation with an AC current. It should be DC current to
restore the residual megnetism which has lost due to not using for a
long time.

I googled and found an articles after reading this, that made a little
sence.

http://www.findarticles.com/p/articl...42/ai_55463575

you should first try with a Battery and then starting the generator
with good load. It should work.

Excitation with 120V 60 Hz AC with a bulb in series should require
only for big industrial generators.

Regards,

Suraj


"ray" wrote in message ...
Thanks Fred & James,
Your interest & advice is much appreciated.

I did get a response from another newsgroup, which advised me to have a look
at http://www.endtimesreport.com/dead_gen.html .

It turned out to be a comprehensive article entitled "RE-ENERGIZING DEAD
GENERATORS " (2.5 pages)

In short, it suggests a way of doing it by connecting the output of a spare
generator to the output of the dead generator, while the dead generator is
being driven by the petrol engine ?? uses three 60 watt globes in series
in the connecting line. ??

I am hesitant in trying this procedure, as we are talking about 240 volts
AC.....

If you could have a look at this article and give me your opinion before I
take an action that could turn out to be a really bad thing....

regards Ray

  #9   Report Post  
Fred McKenzie
 
Posts: n/a
Default

That sounds kinda dangerous! I suggest a safer route, take a 6v lantern
battery, or some D batteries in series, a 12v gel-cell, whatever and connect
it to the output of the dead generator for a few seconds.

Ray & James et al-

I agree that the 120 VAC method presents some hazards that would best be
avoided. The battery approach would certainly be easy to try, and I think it
would work. I think a quick touch should do it.

One of the references mentioned a problem if the battery was connected
backwards. I believe that was with regard to a DC generator, not an AC
generator like the Honda.

In this case, I don't think it should make any difference which polarity is
used. If someone knows different, please speak up!

Fred

  #11   Report Post  
Fred McKenzie
 
Posts: n/a
Default

Fred, how does the iron lose all its magnetism in the first place?
I thought that by design there was always supposed to be enough
residual magnetism to bootstrap the generator.

Asimov-

I don't know how, but it apparently happens on rare (?) occasion. Perhaps the
earth's magnetic field happens to oppose the residual field due to the
orientation of the generator while in storage.

I once worked at a place where they made their own permanent magnets used for
focusing an electron beam in a traveling wave tube. The field of these magnets
was very critical for their application. They were sensitive to shock, as I
recall. If one were dropped it would require re-magnetization or
recalibration.

These magnets were "designed" to retain magnetism by virtue of the choice of
the metal alloy. I don't think most alternators or generators use anything
special, just iron. One of the references mentioned earlier, suggested that a
small permanent magnet was sometimes attached to the iron just for this
purpose.

I looked at the manual for my Sears/Generac 3500 watt generator. There was no
mention of re-polarization, and no permanent magnet was listed in any of the
parts lists. It has sat idle for several years at a time, and when restarted
has always delivered rated voltage. (I did have to replace the carburetor
once!)

Fred

  #12   Report Post  
jakdedert
 
Posts: n/a
Default


"Fred McKenzie" wrote in message
...
Fred, how does the iron lose all its magnetism in the first place?
I thought that by design there was always supposed to be enough
residual magnetism to bootstrap the generator.

Asimov-

I don't know how, but it apparently happens on rare (?) occasion. Perhaps

the
earth's magnetic field happens to oppose the residual field due to the
orientation of the generator while in storage.

I once worked at a place where they made their own permanent magnets used

for
focusing an electron beam in a traveling wave tube. The field of these

magnets
was very critical for their application. They were sensitive to shock, as

I
recall. If one were dropped it would require re-magnetization or
recalibration.


The earths field is stronger than most imagine from everyday experience.
One can induce a weak magnetic field in a piece of soft iron (like rebar)
simply by orienting it north and south on it's long axis, and striking with
a hammer along that same axis. Afterward, the formerly unmagnitized bar
will have enough magnetism to pick up staples, iron filings and the like.

Maybe that's the solution for the OP: simply whack it (really hard) with a
hammer! Works for a lot of other things.... ;-)

jak


These magnets were "designed" to retain magnetism by virtue of the choice

of
the metal alloy. I don't think most alternators or generators use

anything
special, just iron. One of the references mentioned earlier, suggested

that a
small permanent magnet was sometimes attached to the iron just for this
purpose.

I looked at the manual for my Sears/Generac 3500 watt generator. There

was no
mention of re-polarization, and no permanent magnet was listed in any of

the
parts lists. It has sat idle for several years at a time, and when

restarted
has always delivered rated voltage. (I did have to replace the carburetor
once!)

Fred



  #13   Report Post  
Jeff Rigby
 
Posts: n/a
Default


"jakdedert" wrote in message
. ..

"Fred McKenzie" wrote in message
...
Fred, how does the iron lose all its magnetism in the first place?
I thought that by design there was always supposed to be enough
residual magnetism to bootstrap the generator.

Asimov-

I don't know how, but it apparently happens on rare (?) occasion.

Perhaps
the
earth's magnetic field happens to oppose the residual field due to the
orientation of the generator while in storage.

I once worked at a place where they made their own permanent magnets

used
for
focusing an electron beam in a traveling wave tube. The field of these

magnets
was very critical for their application. They were sensitive to shock,

as
I
recall. If one were dropped it would require re-magnetization or
recalibration.


The earths field is stronger than most imagine from everyday experience.
One can induce a weak magnetic field in a piece of soft iron (like rebar)
simply by orienting it north and south on it's long axis, and striking

with
a hammer along that same axis. Afterward, the formerly unmagnitized bar
will have enough magnetism to pick up staples, iron filings and the like.

Maybe that's the solution for the OP: simply whack it (really hard) with a
hammer! Works for a lot of other things.... ;-)

jak


These magnets were "designed" to retain magnetism by virtue of the

choice
of
the metal alloy. I don't think most alternators or generators use

anything
special, just iron. One of the references mentioned earlier, suggested

that a
small permanent magnet was sometimes attached to the iron just for this
purpose.

I looked at the manual for my Sears/Generac 3500 watt generator. There

was no
mention of re-polarization, and no permanent magnet was listed in any of

the
parts lists. It has sat idle for several years at a time, and when

restarted
has always delivered rated voltage. (I did have to replace the

carburetor
once!)

Fred

My Sears generator has a power suppply transformer attached. The only
reason for this was excitation of the fields from an alt (permanent magnet
in generator)


  #14   Report Post  
Jim Adney
 
Posts: n/a
Default

On Sunday, 29 Aug 2004 00:20:10 -500 "Asimov"
wrote:

Fred, how does the iron lose all its magnetism in the first place?
I thought that by design there was always supposed to be enough
residual magnetism to bootstrap the generator...


You're right that there's little reason for residual magnetism to go
away. An automotive generator can sit for years or decades and still
be fine.

That's just for DC generators, however. I don't think there are any AC
generators of any significant power that use residual magnetism to
bootstrap themselves. They all require a bit of current from some
source to get themselves started.

The one exception might be brushless AC generators, which I thought
were rare. They could be designed to use residual magnetism to get
going.

Does this AC generator have any brushes?

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------
  #15   Report Post  
ray
 
Posts: n/a
Default


"Jim Adney" wrote in message
...
On Sunday, 29 Aug 2004 00:20:10 -500 "Asimov"
wrote:

Fred, how does the iron lose all its magnetism in the first place?
I thought that by design there was always supposed to be enough
residual magnetism to bootstrap the generator...


You're right that there's little reason for residual magnetism to go
away. An automotive generator can sit for years or decades and still
be fine.

That's just for DC generators, however. I don't think there are any AC
generators of any significant power that use residual magnetism to
bootstrap themselves. They all require a bit of current from some
source to get themselves started.

The one exception might be brushless AC generators, which I thought
were rare. They could be designed to use residual magnetism to get
going.

Does this AC generator have any brushes?

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

Yes Jim, the generator does have brushes
regards
Ray





  #16   Report Post  
James Sweet
 
Posts: n/a
Default


"Jim Adney" wrote in message
...
On Sunday, 29 Aug 2004 00:20:10 -500 "Asimov"
wrote:

Fred, how does the iron lose all its magnetism in the first place?
I thought that by design there was always supposed to be enough
residual magnetism to bootstrap the generator...


You're right that there's little reason for residual magnetism to go
away. An automotive generator can sit for years or decades and still
be fine.

That's just for DC generators, however. I don't think there are any AC
generators of any significant power that use residual magnetism to
bootstrap themselves. They all require a bit of current from some
source to get themselves started.

The one exception might be brushless AC generators, which I thought
were rare. They could be designed to use residual magnetism to get
going.

Does this AC generator have any brushes?


Quite a few portable generators excite themselves from residual magnetism,
and yes they have brushes on slip rings.


  #17   Report Post  
Jim Adney
 
Posts: n/a
Default

On Tue, 31 Aug 2004 02:14:48 GMT "James Sweet"
wrote:

Quite a few portable generators excite themselves from residual magnetism,
and yes they have brushes on slip rings.


I'm always glad to learn something new, but then I have to wonder why
automotive AC generators (alternators) don't do this.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------
  #18   Report Post  
James Sweet
 
Posts: n/a
Default


"Jim Adney" wrote in message
...
On Tue, 31 Aug 2004 02:14:48 GMT "James Sweet"
wrote:

Quite a few portable generators excite themselves from residual

magnetism,
and yes they have brushes on slip rings.


I'm always glad to learn something new, but then I have to wonder why
automotive AC generators (alternators) don't do this.



Because they have a battery to do it for them. The field coil is powered
through the voltage regulator which recieves power from the battery when the
ignition is on.


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Portable Generator once more.. Chuck Home Repair 48 July 4th 05 04:52 PM
Portable Generator, Advice on which one to buy Cal Mac UK diy 2 July 25th 04 09:12 PM
Generator FAQ Gunner Metalworking 0 January 23rd 04 05:24 PM


All times are GMT +1. The time now is 12:16 PM.

Powered by vBulletin® Copyright ©2000 - 2023, Jelsoft Enterprises Ltd.
Copyright 2004-2023 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"