Brushless generator overcharging

[Drkuhar]

Need generator repair advice. We had bad storms and lost power for 31 hrs. My wife turned on the central air while my mcculloch brushless 5700 watt generator was powering us and it seemed to hold up so i didnt question it, and after about 3 hours it quit.
I found the capacitor puffed out and took it to a fan repair guy that had a microfarad tester and i verified it was bad.
My original is a 24 microfarad. The ones i found online had all the same specs but 25 microfarad. I figured with the plus or minus numbers allowed i would be fine . So ordered one

After getting it back together i am getting over voltage readings. My 110 outlets that use to run anout 118-120 are running 128-130 volts and my 220 i never measured before is but i know can be 240 is running 255-260.

Is it the one microfarad capacitor difference or is something else going on, any ideas
Thanks
Update
No schematic, just an exploded parts diagram. I tested the generator windings with a multimeter and youtube videos( generator guru) of running with no capacitor the leads should be at 5v +/- 2volts and i read 3.87v.
The dianz is the bad cap. Jcm is new. I tried a 30uf that the fan repair guy had and it was at 138v on ny 110/120 outlets.

 

[mark-NJ]

What / which capacitor went bad? The exciter? I can't imagine how 1uF would affect the voltage regulation that much. The cap is really just for excitation... Got a schematic?

 

[larry_g]

I posted about this in a thread I started. You'll have to search it out as I'm not on a computer, strange phone.
Lg

 

[Drkuhar]

What / which capacitor went bad? The exciter? I can't imagine how 1uF would affect the voltage regulation that much. The cap is really just for excitation... Got a schematic?

Edit main post to add pics. No schematic just exploded parts diagram. There was only one capacitor under the back cover where the outlets were

 

[Drkuhar]

I posted about this in a thread I started. You'll have to search it out as I'm not on a computer, strange phone.
Lg

I found your link and you got 1uf=2.5 volts , i would be happy with that but mine shot up 10 volts with a 1uf change. I dont want to fry anything

 

[BillK]

I found your link and you got 1uf=2.5 volts , i would be happy with that but mine shot up 10 volts with a 1uf change. I dont want to fry anything

So can you not just order the correct one from the manufacturer ????

 

[nadogail]

I agree, if the non specification part made the situation better; maybe a specification conforming part will make things right, rather than just better.

 

[larry_g]

I can only guess that your initial reading of 118-120 were on a cap that was near 24mf and that the 25 mf cap might be a bit on the high side of its rating, can you measure it? I would hope that a couple of the links in my thread could lead you to a manual for your machine.

lg
no neat sig line

 

[dogdog]

here googlefu-ed for you.

https://www.allmand.com/content/dam/allmand/na/en_us/files/support/Coliseum_Generator_Troubleshooting_Guide.pdf

apparently your generator uses this alternator as the electrical generation part. "GSA-L3-2 alternator service manual"

so all you have to do is check the troubleshooting chart maybe ?

 

[Drkuhar]

I couldnt find anything by the part number on amazon and

I can only guess that your initial reading of 118-120 were on a cap that was near 24mf and that the 25 mf cap might be a bit on the high side of its rating, can you measure it? I would hope that a couple of the links in my thread could lead you to a manual for your machine.

lg
no neat sig line

Thats my next step is to take it back out and get it tested and find out if its on the high end of the +/-5 . Im happy that at least i know the generator works and isnt dead in the water

 

[Drkuhar]

here googlefu-ed for you.

https://www.allmand.com/content/dam/allmand/na/en_us/files/support/Coliseum_Generator_Troubleshooting_Guide.pdf

apparently your generator uses this alternator as the electrical generation part. "GSA-L3-2 alternator service manual"

so all you have to do is check the troubleshooting chart maybe ?

I downloaded that thank you

 

[Milton Shaw]

Have you checked the hertz. Most generator, if the hertz is high the motor is running to fast and that ups the voltage too. Check hertz and set governor may cure your problems.

 

[Drkuhar]

Problem fixed i believe. I could not come up with a tester for hertz but i picked up a echo pet1000 small engine tach and i was running 3800 rpms. Dialed the governor screw back just a bit to 3600 and everything is good. I had 121/122v on the 110 outlets. I had 244v on the 220 outlet.

I bought this new and never messed with it. Probably 6 to 8 hours of use over 12 years and now wonder if it had been turned up from the factory to get where it needed to be as it had a sticker by the screw with 60hz written on it.

 

[nadogail]

I measure frequency and engine speed with my Clamp On Amprobe

 

[wyliesdiesels]

Problem fixed i believe. I could not come up with a tester for hertz but i picked up a echo pet1000 small engine tach and i was running 3800 rpms. Dialed the governor screw back just a bit to 3600 and everything is good. I had 121/122v on the 110 outlets. I had 244v on the 220 outlet.

I bought this new and never messed with it. Probably 6 to 8 hours of use over 12 years and now wonder if it had been turned up from the factory to get where it needed to be as it had a sticker by the screw with 60hz written on it.

Well that’ll do it. Needs to be rpm multiples of 900, ie 1800 or 3600. 3800 too high...

 

[TractorJeff]

Now put a FULL Load on it and see what the RPM/Hz drops too.
Generally at No Load they tend to run higher due to the DROOP of the Governor.
At Full Load, You may find your Voltage lower than desired.

 

[AP514]

Mine runs at 3680 RPM no load....61.2 Hrz

 

[dogdog]

Do they sell any sort of inverter boards that turns the basic generator wild output to an pure sine wave output ? Though I saw some board for sale on eBay once. Hmmm thought I have asked this question before also. Oh well

 

[Drkuhar]

Now put a FULL Load on it and see what the RPM/Hz drops too.
Generally at No Load they tend to run higher due to the DROOP of the Governor.
At Full Load, You may find your Voltage lower than desired.

i did a test with some items plugged in and running and it was down to 118/119 so i bumped the governor up to 3680 and voltage went to 122. i feel more confident in this setting now that it has ran with a few items loading it. it took about a 1/8 of a turn to go from 3600 to 3680

 

[dogdog]

i did a test with some items plugged in and running and it was down to 118/119 so i bumped the governor up to 3680 and voltage went to 122. i feel more confident in this setting now that it has ran with a few items loading it. it took about a 1/8 of a turn to go from 3600 to 3680

you don't have to be 120V exactly on AC, it have a tolerance from as low as 90Vac to as high as 140Vacs.. most electronics operates at... I think frequency is a killer.

There was an old post from some Sales guy for Generac that could explain this better ... maybe look it up way way back 2016 I think..

 

[American Locomotive]

Small engine governors are not very good (generally speaking), so the generator manufacturers usually run the small sets a little fast with no load, so under full load the frequency is still acceptable. Usually 61-62 Hz unloaded is typical.

 

[snoyes34231]

Hope this thread is not to old to bring back to life.. I have a similar but different issue..
I bought a used valsi 5500 watt generator with no tank for $80.. taking a chance on everything.. The guy said the tank rusted out and he took it off.. the carb was all corroded and the jet was 100% blocked.. little elbow grease and varrooom.. starts on the first pull.. this gen-set is a brushless, the front panel has a volt meter to 300VAC.. while running full throttle it was showing almost full 300VAC.. UGG.ggg. I went and grabbed a meter. yep.. 150VAC on both legs.. this gen-set has a manual throttle.. if I dial it down and put a 3-4amp load on it, the voltage is 110-120, but if I crank it up.. it's 150VAC.. After finding the Generator-guru.. and his video of testing the leads to the cap, removed and engine running, I'm getting 9.05 to 9.20 VAC.. He says it should be at 5VAC +-2..
I sent him and email explaining what I found, he reponded

" Dear Scott,

Unfortunetly your results indicated the rotor has failed you need to contact a local “Motor Rewind Company” to see if they can fix it. These companies can vary in price, so if you have time, it is worth getting a few quotes.

This is a much cheaper option than replacing the Alternator as the manufacturer charges over ½ the price of a new Generator and we would still need to get it shipped to you from China. Being so heavy, that would be very expensive and outweighs the economy of a new Alternator."

Any way to add a regulator type contrapion to the mix? I could just save it for emergency low power applications, where it might be a constant draw that i could monitor on a meter and adjust the rpm to match the required output?

Or just trash it? Too bad tapered shaft Motors can't be utilized for other projects very easily. The motor purrs.. just had to clean up the corrosion from the Ethanol scam..

Open for suggestions..​

​

 

[theoldwizard1]

After getting it back together i am getting over voltage readings. My 110 outlets that use to run anout 118-120 are running 128-130 volts and my 220 i never measured before is but i know can be 240 is running 255-260.

The standard voltage in the US is 120/240 +/-10%. 130 is still within spec for a 120V outlet. 260V is within spec for a 240V outlet.

In general, brushless generators make very "dirty" power. It probably won't affect motors or incandescent or florescent lights. Not great for electronics !

 

[theoldwizard1]

I went and grabbed a meter. yep.. 150VAC on both legs.. this gen-set has a manual throttle.. if I dial it down ...

No AC generator I have ever has a MANUAL throttle. Engine speed affect both voltage and frequency. Frequency is more important because anything more than about +/-5% (3Hz) can have a negative affect on motors (assuming the output is a good sine wave and the voltage is within spec).

 

[snoyes34231]

This generator has one.. see attached.. I'll fire it up again and check the Hz at couple different throttle positions

 

[wyliesdiesels]

The standard voltage in the US is 120/240 +/-10%. 130 is still within spec for a 120V outlet. 260V is within spec for a 240V outlet.

In general, brushless generators make very "dirty" power. It probably won't affect motors or incandescent or florescent lights. Not great for electronics !

It may be in spec for the receptacle however most Pocos have a +/- 5% tolerance for voltage levels. Past that they will dispatch to fix the under or over voltage issue

 

[ihateminimumwage]

Hope this thread is not to old to bring back to life.. I have a similar but different issue..
I bought a used valsi 5500 watt generator with no tank for $80.. taking a chance on everything.. The guy said the tank rusted out and he took it off.. the carb was all corroded and the jet was 100% blocked.. little elbow grease and varrooom.. starts on the first pull.. this gen-set is a brushless, the front panel has a volt meter to 300VAC.. while running full throttle it was showing almost full 300VAC.. UGG.ggg. I went and grabbed a meter. yep.. 150VAC on both legs.. this gen-set has a manual throttle.. if I dial it down and put a 3-4amp load on it, the voltage is 110-120, but if I crank it up.. it's 150VAC.. After finding the Generator-guru.. and his video of testing the leads to the cap, removed and engine running, I'm getting 9.05 to 9.20 VAC.. He says it should be at 5VAC +-2..
I sent him and email explaining what I found, he reponded

" Dear Scott,

Unfortunetly your results indicated the rotor has failed you need to contact a local “Motor Rewind Company” to see if they can fix it. These companies can vary in price, so if you have time, it is worth getting a few quotes.

This is a much cheaper option than replacing the Alternator as the manufacturer charges over ½ the price of a new Generator and we would still need to get it shipped to you from China. Being so heavy, that would be very expensive and outweighs the economy of a new Alternator."

Any way to add a regulator type contrapion to the mix? I could just save it for emergency low power applications, where it might be a constant draw that i could monitor on a meter and adjust the rpm to match the required output?

Or just trash it? Too bad tapered shaft Motors can't be utilized for other projects very easily. The motor purrs.. just had to clean up the corrosion from the Ethanol scam..

Open for suggestions..​

​

Your rotor isn't bad if you're making voltage high/lo. Cap regulated is based off of your engine speed/HZ and the capacitor mF installed. The voltage will ramp up with load. You need to meter the frequency as it's running unloaded to fully loaded, and adjust your governor position at the throttle linkage for speed droop. Old air cooled units with worn governors are a real pain to get dialed in.