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Discussion Starter · #1 ·
Greetings all (new here),

Bear with me in case I mess something up. Ok, to the point with my question;

I have a COLEMAN VERTEX 7850 GENERATOR that quit "putting out". I was one of those almost wiped out (again) by Hurricane Irma in Orlando, Florida last week.

1) The aforementioned generator was purchased in 2004/5 after we got clobbered by 4 infamous storms.

2) This generator is started one or two times per month and operated for 20 minutes each time to keep everything lubed and ready to go.

3) When we first lost power, I hooked up gen in my normal fashion which ran my house and my neighbors house w/out any issues.

4) I had the gen running for 3 days and shut it down by removing the load to it and turning it off to refill gas and check oil. Oil was down the width of a pencil lead so, I topped it off with the appropriate oil.

5) I re-started the generator, applied the load one load at a time as to not surge or over draw on the gen and noticed the gen was not putting out any power whatsoever.

6) I checked all connections and used an independent volt meter to read voltages and checked circuit breakers.

7) I attempted to flash the gen by applying voltage to the brushes as the owners manual suggests and did this multiple times with no results.

8) I removed the brushes and inspected same and they were fine and barely worn with such little use.

9) I leaned the gen over to see about removing end bell and as you can see in the attached picts (*wrote this before I found no icon to attach picts) , two brush holders, a center bolt, and four LONG bolts that apparently attach the gen to the motor (brigs).

10) How the XXXX do I remove the black "end cap bell" from the gen? There are electronics under it that I can see that I want to inspect.

a) If I remove the four long bolts, will the gen come crashing down?
b) Can I remove the end bell only after removing the four long bolts?
c) There is that center bolt visible at the black end-cap that I assume is the
end bearing and if it is, won't removal cause the rotating mass to fall into
it's "encasement"?


Any help would be appreciated. I was an electrician by trade but, never had to screw around with generators in their troubleshooting, dis-assembly, or repair. Thanks in advance for your assistance!
 

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I'd have to see a manual with exploded diagram. Can you take an ohm reading of the rotor? I would think if you couldn't get partial voltage out of it by putting some dc to the rotor, possible bad rotor or stator.
 

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Discussion Starter · #3 ·
I'd have to see a manual with exploded diagram. Can you take an ohm reading of the rotor? I would think if you couldn't get partial voltage out of it by putting some dc to the rotor, possible bad rotor or stator.
*********************

Thanks for the reply!

As my initial posts states - I am looking to get the end bell off and, I see no way to access anything unless i do so....I got no voltage after failure and no voltage after my attempt at flashing.....This unit has NEVER been overloaded and has only approx. 85 intermittent hours on it not including the every month start up.
 

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If you can take an ohm reading across the slip rings, I'd guess maybe a value 9-22ohms. Stator readings are really low. You put like 12v dc to the rotor, from the electric start battery?

Do you have an actual model number? Trying to find something useful on the powermate website.
 

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Discussion Starter · #6 ·
Thanks for the reply.

I will re-state all this again;

I cannot access anything unless I remove the end cap bell. Resistance readings and the like will be NOT relevant unless the end comes off for me to accomplish that/this....I see of no way to attach picts here in this forum else I would have.
 

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The picture thing is something I have to figure out again. Others better versed in that hopefully can help. Was hoping if you got at the brushes, you could get at the slip rings. This a vertical mounted generator?
 

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Thanks for the reply.

I will re-state all this again;

I cannot access anything unless I remove the end cap bell. Resistance readings and the like will be NOT relevant unless the end comes off for me to accomplish that/this....I see of no way to attach picts here in this forum else I would have.
did you try to use the paperclip logo it may help you some but being that you are a new member in here you will need at least 20 posting before the picture attachment work properly.

did you check the AVR ? sometime some generators do used the capacitor for AVR function.

there should be a small opening on back end of generator that you can open up and see what is going on and yes some of portable generators do have 12 volt stator coil in the main stator and if you see that burnted then it will not make any power at all.
 

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Discussion Starter · #9 ·
The picture thing is something I have to figure out again. Others better versed in that hopefully can help. Was hoping if you got at the brushes, you could get at the slip rings. This a vertical mounted generator?
*******************
I can pop a blank cover off the end of the generator and remove the brushes but, the "lug" connector connecting to each brush is extreemly short and tends to want to slide back into the bell cover. Yes, this is a vertically mounted gen.
 

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Discussion Starter · #11 ·
did you try to use the paperclip logo it may help you some but being that you are a new member in here you will need at least 20 posting before the picture attachment work properly.

did you check the AVR ? sometime some generators do used the capacitor for AVR function.

there should be a small opening on back end of generator that you can open up and see what is going on and yes some of portable generators do have 12 volt stator coil in the main stator and if you see that burnted then it will not make any power at all.
********************
Thanks for the reply....Suppose i will have to wait for "20" to come up to post picts which will better explain the situation....As I have stated, I cannot acess a darned thing w/out the end cap off.....The manual indicated to apply a 6vdc source such as from a lantern battery to the brushes momentarily and attempt to re-start and, if that doesn't work, to repeat the procedure. I have to get this up and running since losing almost everything in 2004 and last week the same.
 

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Didn't see that ok. Usually putting DC to that will get you at least partial voltage if the windings are good. Both rotor and stator. Wondering if now somethings opened up.
 

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Discussion Starter · #15 ·
We don't usually split small units like that.
Maybe try smokstak.com

https://www.smokstak.com/forum/showthread.php?t=68414

**************************


Thanks for the reply...I have 4 e-mails out with an attached pict to the site mentioned and not a single reply....This is a 275lb beast and not small unless you compare it to the industrial units.

If I unscrew the 4 LONG BOLTS there is still a bolt dead center of the bell cover with the brushes at each side of it. I do not want to damage any rotating masses and not sure what needs to be "undone" to get at the electronic components i need to inspect.
 

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Discussion Starter · #16 ·
Didn't see that ok. Usually putting DC to that will get you at least partial voltage if the windings are good. Both rotor and stator. Wondering if now somethings opened up.
****************

I couldn't say only that it was producing smooth consistent voltage and not even using 1/3 of its rated run capacity...Heck, All I did was shut it off and ck oil and refill gas as in my initial first post...Doubt any burns or open/shorted windings.
 

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Didn't see that ok. Usually putting DC to that will get you at least partial voltage if the windings are good. Both rotor and stator. Wondering if now somethings opened up.
That I been wondering about that and with single bangers ( single cylinder engines ) intened to make a bit of viberations so any one of the connection can get loosen over the time and with most gasoline portable generator useally spin at 3600 RPM so something have to give away with that high a rpm plus viberation.,,

To OP check the rotor recficter to make sure the connection is soldered good as I mention above those is one of few common cuprits on small gasoline or diesel two pole generators.
 

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********************
Thanks for the reply....Suppose i will have to wait for "20" to come up to post picts which will better explain the situation....As I have stated, I cannot acess a darned thing w/out the end cap off.....The manual indicated to apply a 6vdc source such as from a lantern battery to the brushes momentarily and attempt to re-start and, if that doesn't work, to repeat the procedure. I have to get this up and running since losing almost everything in 2004 and last week the same.
6 volts will not do it .,, you need at least 12 volts to kick it good you can flash it either at rotor connection or stator either one will kick start the generator side. but before you do that as I mention my recent posting the viberation can make any connection come loose so check everything what you can able reach in.
 

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Discussion Starter · #19 ·
That I been wondering about that and with single bangers ( single cylinder engines ) intened to make a bit of viberations so any one of the connection can get loosen over the time and with most gasoline portable generator useally spin at 3600 RPM so something have to give away with that high a rpm plus viberation.,,

To OP check the rotor recficter to make sure the connection is soldered good as I mention above those is one of few common cuprits on small gasoline or diesel two pole generators.
***************

Thanks for the reply.

As I stated, I cannot access anything....I have checked ALL exposed or accessible wiring and connections and find no anomalies.
 

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Maybe a little more than 3600 when mechanically governed, looking for about 62.5hz no load. Stuff goes with normal use too, unfortunately. The big question is, not having access to part numbers, is once you find out what's wrong, are parts available? Powermate is or was Pramac, both now under the Generac banner.
 
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