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Generac 7550 Generator



 
 
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  #1  
Old March 31st 07, 08:47 PM posted to alt.home.repair
external usenet poster
 
Posts: 3
Default Generac 7550 Generator

I've got a Generac Generator that has no power output. A friend who is
a very good mechanic has looked at it and found that it has no power
output from the plug that comes from the base of the generator. He
measured 5 volts AC from ground to hot in the plug.

Inside the "cap" that fits over the base of the generator, he found a
wire that was burnt in half that goes to a module of some sort. He
said the module has several circuit boards and various electronic
components.

He said he has no way of knowing the proper way to troubleshoot the
module to see if it is the problem.

Can anyone tell me anything that would help with this?

Should I just take it to a reputable repair place now instead of doing
more with my friends help?

He also checked all of the output points on the panel and found all
the outlets good. The breakers are also good and the switch for the
breakers tested good he said.

When the unit is running, he said it appears to be working fine
mechanically. The motor is running very well and he said the generator
is operating, but not outputting from the plug on the panel side of
the module in question.

Thank you for any help you may be able to give.
Ads
  #2  
Old March 31st 07, 11:34 PM posted to alt.home.repair
external usenet poster
 
Posts: 6,205
Default Generac 7550 Generator

On Mar 31, 2:47?pm, The Fisherman wrote:
I've got a Generac Generator that has no power output. A friend who is
a very good mechanic has looked at it and found that it has no power
output from the plug that comes from the base of the generator. He
measured 5 volts AC from ground to hot in the plug.

Inside the "cap" that fits over the base of the generator, he found a
wire that was burnt in half that goes to a module of some sort. He
said the module has several circuit boards and various electronic
components.

He said he has no way of knowing the proper way to troubleshoot the
module to see if it is the problem.

Can anyone tell me anything that would help with this?

Should I just take it to a reputable repair place now instead of doing
more with my friends help?

He also checked all of the output points on the panel and found all
the outlets good. The breakers are also good and the switch for the
breakers tested good he said.

When the unit is running, he said it appears to be working fine
mechanically. The motor is running very well and he said the generator
is operating, but not outputting from the plug on the panel side of
the module in question.

Thank you for any help you may be able to give.


modules fail and are expensive, at least a few years ago when mine
failed twice.

my best friend a electrical engineer tossed the module and added a
heavy duty switch. start generator normally, once its running stable
with no power out you push button, it excites generator, like a start
switch. you only hold it a very short time or you will burn out the
start windings. has worked fine since.

modules must be a big profit item for generac no drawings or board
parts availble, one big secret. $$$$

  #3  
Old April 1st 07, 03:50 PM posted to alt.home.repair
external usenet poster
 
Posts: 1
Default Generac 7550 Generator

On 31 Mar 2007 15:34:25 -0700, "
wrote:

On Mar 31, 2:47?pm, The Fisherman wrote:
I've got a Generac Generator that has no power output. A friend who is
a very good mechanic has looked at it and found that it has no power
output from the plug that comes from the base of the generator. He
measured 5 volts AC from ground to hot in the plug.

Inside the "cap" that fits over the base of the generator, he found a
wire that was burnt in half that goes to a module of some sort. He
said the module has several circuit boards and various electronic
components.

He said he has no way of knowing the proper way to troubleshoot the
module to see if it is the problem.

Can anyone tell me anything that would help with this?

Should I just take it to a reputable repair place now instead of doing
more with my friends help?

He also checked all of the output points on the panel and found all
the outlets good. The breakers are also good and the switch for the
breakers tested good he said.

When the unit is running, he said it appears to be working fine
mechanically. The motor is running very well and he said the generator
is operating, but not outputting from the plug on the panel side of
the module in question.

Thank you for any help you may be able to give.


modules fail and are expensive, at least a few years ago when mine
failed twice.

my best friend a electrical engineer tossed the module and added a
heavy duty switch. start generator normally, once its running stable
with no power out you push button, it excites generator, like a start
switch. you only hold it a very short time or you will burn out the
start windings. has worked fine since.

modules must be a big profit item for generac no drawings or board
parts availble, one big secret. $$$$


Thank you very much for your reply. I have a couple more questions for
you if you would be so kind as to inform me:

Can you tell me exactly how to have the switch made? I have a friend
who is an electronics tech, and he can make it and install it if he
knew what to do. If a schematic of the installation is available from
your friend, I would be in your debt. I could post a disposable email
address for you to send it to.

Secondly, how much did the module cost that you replaced and how much
labor did they charge you. I have to get this thing working. I live in
the heart of hurricane areas in Florida. Hehe, the fishing is great.

Again, thank you very much for your time and information.
  #4  
Old April 1st 07, 05:02 PM posted to alt.home.repair
external usenet poster
 
Posts: 6,205
Default Generac 7550 Generator

On Apr 1, 10:50?am, Terrorist Killer wrote:
On 31 Mar 2007 15:34:25 -0700, "
wrote:





On Mar 31, 2:47?pm, The Fisherman wrote:
I've got a Generac Generator that has no power output. A friend who is
a very good mechanic has looked at it and found that it has no power
output from the plug that comes from the base of the generator. He
measured 5 volts AC from ground to hot in the plug.


Inside the "cap" that fits over the base of the generator, he found a
wire that was burnt in half that goes to a module of some sort. He
said the module has several circuit boards and various electronic
components.


He said he has no way of knowing the proper way to troubleshoot the
module to see if it is the problem.


Can anyone tell me anything that would help with this?


Should I just take it to a reputable repair place now instead of doing
more with my friends help?


He also checked all of the output points on the panel and found all
the outlets good. The breakers are also good and the switch for the
breakers tested good he said.


When the unit is running, he said it appears to be working fine
mechanically. The motor is running very well and he said the generator
is operating, but not outputting from the plug on the panel side of
the module in question.


Thank you for any help you may be able to give.


modules fail and are expensive, at least a few years ago when mine
failed twice.


my best friend a electrical engineer tossed the module and added a
heavy duty switch. start generator normally, once its running stable
with no power out you push button, it excites generator, like a start
switch. you only hold it a very short time or you will burn out the
start windings. has worked fine since.


modules must be a big profit item for generac no drawings or board
parts availble, one big secret. $$$$


Thank you very much for your reply. I have a couple more questions for
you if you would be so kind as to inform me:

Can you tell me exactly how to have the switch made? I have a friend
who is an electronics tech, and he can make it and install it if he
knew what to do. If a schematic of the installation is available from
your friend, I would be in your debt. I could post a disposable email
address for you to send it to.

Secondly, how much did the module cost that you replaced and how much
labor did they charge you. I have to get this thing working. I live in
the heart of hurricane areas in Florida. Hehe, the fishing is great.

Again, thank you very much for your time and information.- Hide quoted text -

- Show quoted text -


They wanted at the time 75 bucks for the module and 150 to service the
generator. So I had them do it.

on its second use the module blew again

my buddy came to my rescue..... I dont need the generator often will
ask him tomorrow for a wiring drawing, the momentary contact switch is
heavy duty but nothing special, t the time he said it connects the
start winding, which excites the generator. you push it justy long
enough to hear engine speed drop a little which means its generating.

will see him monday. glad to be of help

  #5  
Old April 1st 07, 09:41 PM posted to alt.home.repair
external usenet poster
 
Posts: 3,108
Default Generac 7550 Generator

" wrote in
ups.com:

On Apr 1, 10:50?am, Terrorist Killer wrote:
On 31 Mar 2007 15:34:25 -0700, "
wrote:





On Mar 31, 2:47?pm, The Fisherman wrote:
I've got a Generac Generator that has no power output. A friend
who is a very good mechanic has looked at it and found that it has
no power output from the plug that comes from the base of the
generator. He measured 5 volts AC from ground to hot in the plug.


Inside the "cap" that fits over the base of the generator, he
found a wire that was burnt in half that goes to a module of some
sort. He said the module has several circuit boards and various
electronic components.


He said he has no way of knowing the proper way to troubleshoot
the module to see if it is the problem.


Can anyone tell me anything that would help with this?


Should I just take it to a reputable repair place now instead of
doing more with my friends help?


He also checked all of the output points on the panel and found
all the outlets good. The breakers are also good and the switch
for the breakers tested good he said.


When the unit is running, he said it appears to be working fine
mechanically. The motor is running very well and he said the
generator is operating, but not outputting from the plug on the
panel side of the module in question.


Thank you for any help you may be able to give.


modules fail and are expensive, at least a few years ago when mine
failed twice.


my best friend a electrical engineer tossed the module and added a
heavy duty switch. start generator normally, once its running stable
with no power out you push button, it excites generator, like a
start switch. you only hold it a very short time or you will burn
out the start windings. has worked fine since.


modules must be a big profit item for generac no drawings or board
parts availble, one big secret. $$$$


Thank you very much for your reply. I have a couple more questions
for you if you would be so kind as to inform me:

Can you tell me exactly how to have the switch made? I have a friend
who is an electronics tech, and he can make it and install it if he
knew what to do. If a schematic of the installation is available from
your friend, I would be in your debt. I could post a disposable email
address for you to send it to.

Secondly, how much did the module cost that you replaced and how much
labor did they charge you. I have to get this thing working. I live
in the heart of hurricane areas in Florida. Hehe, the fishing is
great.

Again, thank you very much for your time and information.- Hide
quoted text -

- Show quoted text -


They wanted at the time 75 bucks for the module and 150 to service the
generator. So I had them do it.

on its second use the module blew again


what about their repair warranty?
How long a time passed between the repair and the failure?
Maybe an email to the company might get you another generator to replace
your "lemon".

my buddy came to my rescue..... I dont need the generator often will
ask him tomorrow for a wiring drawing, the momentary contact switch is
heavy duty but nothing special, t the time he said it connects the
start winding, which excites the generator. you push it justy long
enough to hear engine speed drop a little which means its generating.

will see him monday. glad to be of help



I wonder if the module PCBs are servicable separately?
A good tech might be able to find what failed,and perhaps suggest an
improvement. Do you still have the old module,or did the service center
keep it?(maybe THEY repaired the failed part in the original module??)

--
Jim Yanik
jyanik
at
kua.net
  #6  
Old April 8th 07, 11:01 PM posted to alt.home.repair
external usenet poster
 
Posts: 3
Default Generac 7550 Generator

On 1 Apr 2007 09:02:38 -0700, "
wrote:

I dont need the generator often will
ask him tomorrow for a wiring drawing, the momentary contact switch is
heavy duty but nothing special, t the time he said it connects the
start winding, which excites the generator. you push it justy long
enough to hear engine speed drop a little which means its generating.

will see him monday. glad to be of help


Were you able to contact your friend? I've taken my generator to a
shop for repair. They tell me I'll have it back towards the end of
this coming week.

If I were to have a schematic for what your friend did, perhaps I
could use it next time.

  #7  
Old April 9th 07, 01:18 PM posted to alt.home.repair
external usenet poster
 
Posts: 6,205
Default Generac 7550 Generator

On Apr 8, 6:01?pm, The Fisherman wrote:
On 1 Apr 2007 09:02:38 -0700, "
wrote:

I dont need the generator often will
ask him tomorrow for a wiring drawing, the momentary contact switch is
heavy duty but nothing special, t the time he said it connects the
start winding, which excites the generator. you push it justy long
enough to hear engine speed drop a little which means its generating.


will see him monday. glad to be of help


Were you able to contact your friend? I've taken my generator to a
shop for repair. They tell me I'll have it back towards the end of
this coming week.

If I were to have a schematic for what your friend did, perhaps I
could use it next time.


he found a intermittent open start winding, patched that and installed
the switch.

The board is potted in plastic and no schematics are available.

when I heard what he did I knew it didnt lend itself well to
explaining on the net. hopefully the service folks will get it working
well, but try it a ferw times before you put it in storage so you will
know its working.

mine worked great, tried it once, put in storage, 3 day outage is when
I found it dead.

  #8  
Old May 3rd 07, 04:39 PM posted to alt.home.repair
external usenet poster
 
Posts: 9
Default Generac 7550 Generator

On Apr 9, 8:18 am, " wrote:
On Apr 8, 6:01?pm, The Fisherman wrote:





On 1 Apr 2007 09:02:38 -0700, "
wrote:


I dont need thegeneratoroften will
ask him tomorrow for a wiring drawing, the momentary contact switch is
heavy duty but nothing special, t the time he said it connects the
start winding, which excites thegenerator. you push it justy long
enough to hear engine speed drop a little which means its generating.


will see him monday. glad to be of help


Were you able to contact your friend? I've taken mygeneratorto a
shop for repair. They tell me I'll have it back towards the end of
this coming week.


If I were to have a schematic for what your friend did, perhaps I
could use it next time.


he found a intermittent open start winding, patched that and installed
the switch.

The board is potted in plastic and no schematics are available.

when I heard what he did I knew it didnt lend itself well to
explaining on the net. hopefully the service folks will get it working
well, but try it a ferw times before you put it in storage so you will
know its working.

mine worked great, tried it once, put in storage, 3 day outage is when
I found it dead.


Well, here's the update after getting it repaired.

I was told that when the wire coming from the control module was cut
by vibration due to improper routing, that the generator continued to
spin for some time and caused the magnetic field of the generator to
become confused.

The shop followed Generac's instructions and hooked up a DC power
supply to the slip rings of the generator and realigned the magnetic
field. After doing so, it works fine.

Has anyone ever heard of this?

If not, I'm going to call Generac myself and have them explain how and
why this happened.

I'm not sure I believe this explanation that cost me $275.00

If someone HAS heard of this or at least understands how this really
works, please tell me.

Thank you.


  #9  
Old May 3rd 07, 08:07 PM posted to alt.home.repair
external usenet poster
 
Posts: 308
Default Generac 7550 Generator

snip

I was told that when the wire coming from the control module was cut
by vibration due to improper routing, that the generator continued to
spin for some time and caused the magnetic field of the generator to
become confused.

The shop followed Generac's instructions and hooked up a DC power
supply to the slip rings of the generator and realigned the magnetic
field. After doing so, it works fine.

Has anyone ever heard of this?

If not, I'm going to call Generac myself and have them explain how and
why this happened.

I'm not sure I believe this explanation that cost me $275.00

If someone HAS heard of this or at least understands how this really
works, please tell me.

Thank you.


Generators of this type are self-exciting. This means some of the
output of the generator is rectified (converted to DC) and used to
provide the magnetic field that the generator uses to generate
electricity.

This leads to a chicken and egg situation. The generator must be
generating power to provide the magnetic field it needs to generate
power.

The reason this works is due to some residual magnetic field that
remains in the iron when the generator is off. This is enough to get
things going when you start the generator. But...there are a few
things than can cause problems. One is time. If the generator is not
run for a long time, the residual field can decay to the point where
you will get no power output when you start it. Most manufacturers
recommend running the generator for a short while every few weeks.
That will prevent this.

Now, your generator probably uses a brushless alternator, which
complicates the situation somewhat, but the basic principle still
applies. You need a little residual magnetism, in the right places
and with the right orientation, to get things going. I can believe a
problem with the control board, which would be handling commutation of
the brushless alternator, Could mess this up.

So the story you got is at least feasible....

HTH,

Paul

  #10  
Old May 7th 07, 03:48 PM posted to alt.home.repair
external usenet poster
 
Posts: 9
Default Generac 7550 Generator

On May 3, 3:07 pm, Paul Franklin
wrote:
snip







I was told that when the wire coming from the control module was cut
by vibration due to improper routing, that thegeneratorcontinued to
spin for some time and caused the magnetic field of thegeneratorto
become confused.


The shop followedGenerac'sinstructions and hooked up a DC power
supply to the slip rings of thegeneratorand realigned the magnetic
field. After doing so, it works fine.


Has anyone ever heard of this?


If not, I'm going to callGeneracmyself and have them explain how and
why this happened.


I'm not sure I believe this explanation that cost me $275.00


If someone HAS heard of this or at least understands how this really
works, please tell me.


Thank you.


Generators of this type are self-exciting. This means some of the
output of thegeneratoris rectified (converted to DC) and used to
provide the magnetic field that thegeneratoruses to generate
electricity.

This leads to a chicken and egg situation. Thegeneratormust be
generating power to provide the magnetic field it needs to generate
power.

The reason this works is due to some residual magnetic field that
remains in the iron when thegeneratoris off. This is enough to get
things going when you start thegenerator. But...there are a few
things than can cause problems. One is time. If thegeneratoris not
run for a long time, the residual field can decay to the point where
you will get no power output when you start it. Most manufacturers
recommend running thegeneratorfor a short while every few weeks.
That will prevent this.

Now, yourgeneratorprobably uses a brushless alternator, which
complicates the situation somewhat, but the basic principle still
applies. You need a little residual magnetism, in the right places
and with the right orientation, to get things going. I can believe a
problem with the control board, which would be handling commutation of
the brushless alternator, Could mess this up.

So the story you got is at least feasible....

HTH,

Paul


Yes, it did help Paul. Thank you for your explanation. Now I have to
find out exactly how to do this myself. If hooking up a DC power
supply to the "slip rings" is all it takes to resolve this, then I'll
have to learn how to do this properly.

Are there any publications/instructions/diagrams you're aware of that
would help me understand this in a practical sense?

 




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