kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I'm with you on this. When I have seen that kind of voltage POCO had problems on primary side - usually malfunctioning regulator.
utility company power
- Thread starter formula1
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
High voltage will cause the motor windings to saturate and the motor will pull excessive current, per NEMA
- Location
- Massachusetts
So because you have not seen it ............
I have seen as high as 136 line to neutral from the utility. In that case 1950s ballasts were failing rapidly The utility was contacted and they corrected the issue.
The OP never said it was the only item, but 131 is a problem regardless of the motor. So even if it was not the cause of the motor failure it needs to be fixed.
I bet a modern PC or TV would run fine on 131 forever, incandescent lamps not so much.
I agree that is likely, but I also trust that the Op knows how to use and read his meter.
We had one that was fine around 4:00 on a summer afternoon. Apparently the capacitor(internal to the regulator)went bad and the regulator wouldn't step down. You know how many appliances can't handle 142 volts? That is what the voltage went to at around 4:00 in the morning once all the airconditioners had caught up and shut off. Had to shut down the entire circuit to remove the regulator from service...
I know, off topic. I just thought I would throw that out there.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I don't think off topic at all. Pretty much the only reason I have ever seen POCO supply voltage too high, with exception of transients. Not good when a transmission line falls on a local distribution line, that voltage problem does not last long at all but causes a lot of damage, all around town. How is that for being off topic?
- Occupation
- Licensed Electrician
So you are telling me that just because I think I have seen it all does not mean I have. I need to ponder this awhile.So because you have not seen it ............
I have seen as high as 136 line to neutral from the utility. In that case 1950s ballasts were failing rapidly The utility was contacted and they corrected the issue.
I agree if the voltage is that high it is a problem. Now I'm wondering about other people using the same power line; what is happening to them?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
I have run across this only a very few times, and in each case it was a fault between a couple primary windings in the transformer, shorting a few turns in the primary will reduce the pri to sec ratio and raise the voltage on the secondary.
Here they have voltage regulation at the point of use sub stations but not at the transformers serving the local loads, knowing this if you test other service not on the same transformer you can isolate it down to shorted primary turns, if other service are affected that are not on the same transformer then you know its the regulator at the substation feeding the primary high
The last one I came upon was an apartment complex and each 8 plex had its own transformer on the pole, I was getting 144 volts leg to ground and 288 leg to leg, it smoked about 4 furnace motors and a few other items, but I was called out because they kept blowing lamps out, as they didn't realize they had a voltage problem and nether did the HVAC repair guys.
When the line men showed up the foremen immediately started setting up to change out the underground laterals thinking he lost the neutral, I tried to tell him that line to line voltage was also high, he just said so, its the neutral, so I made a call into his supervisor who radioed him to stop, an engineer came out and confirmed my findings and they changed the transformer, and this foreman was sent back to school from what I was told.
But Bob is correct, most electronics today with switch mode power supply's have voltage regulation built in, some can even go from 95 volts to 250 volts with no problems even universal voltage ballast are ok with this (ones rated 120-277 not 120/277) then there are some electronics most likely older stuff that might have a tighter tolerance though, in the above example not one CFL burned out just incandescents, and furnace motors and I think a couple wall warts that had transformers.
I think I made a post about this before back in 2009 or 10?
Here they have voltage regulation at the point of use sub stations but not at the transformers serving the local loads, knowing this if you test other service not on the same transformer you can isolate it down to shorted primary turns, if other service are affected that are not on the same transformer then you know its the regulator at the substation feeding the primary high
The last one I came upon was an apartment complex and each 8 plex had its own transformer on the pole, I was getting 144 volts leg to ground and 288 leg to leg, it smoked about 4 furnace motors and a few other items, but I was called out because they kept blowing lamps out, as they didn't realize they had a voltage problem and nether did the HVAC repair guys.
When the line men showed up the foremen immediately started setting up to change out the underground laterals thinking he lost the neutral, I tried to tell him that line to line voltage was also high, he just said so, its the neutral, so I made a call into his supervisor who radioed him to stop, an engineer came out and confirmed my findings and they changed the transformer, and this foreman was sent back to school from what I was told.
But Bob is correct, most electronics today with switch mode power supply's have voltage regulation built in, some can even go from 95 volts to 250 volts with no problems even universal voltage ballast are ok with this (ones rated 120-277 not 120/277) then there are some electronics most likely older stuff that might have a tighter tolerance though, in the above example not one CFL burned out just incandescents, and furnace motors and I think a couple wall warts that had transformers.
I think I made a post about this before back in 2009 or 10?
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T
T.M.Haja Sahib
Guest
Increased voltage means increased current and if the pool pump motor was already full loaded,this might cause the motor to be over loaded.So the over load protection to the motor might have tripped the motor.So perhaps the motor burnt out due to defective overload protection?
I don't think off topic at all. Pretty much the only reason I have ever seen POCO supply voltage too high, with exception of transients. Not good when a transmission line falls on a local distribution line, that voltage problem does not last long at all but causes a lot of damage, all around town. How is that for being off topic?
I hope to never have that happen to our system!:lol:
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
It has happened here twice 69k line came down on 7200 local line and fused together, sending about 950 volts through all the 120 volt loads, the only way I know that, was it happened when I was running my recorder, lost one house the first time and two houses the second time about 3 years after the first time.
- Location
- Massachusetts
I was working with a power company connecting generators to services while the power company made changes to the system. It was a while ago but if I recall they where switching from delta to wye distribution and doubling the voltage. They had spent a lot of time preparing and placing new transformers all over the place then they powered down and cut everything over ......... except they missed one and they told me they sent the homes on that transformer 240/480 instead of 120/240.
Anyway I went with a power company worker into a guys home, he lost a lot of crap, entertainment equipment, blown Edison base fuses, GFCI duplex burned up pretty impressively.
The power company guy was handing out his business card to the homeowners on that transformer and told them to call with a list of damages.
Anyway I went with a power company worker into a guys home, he lost a lot of crap, entertainment equipment, blown Edison base fuses, GFCI duplex burned up pretty impressively.
The power company guy was handing out his business card to the homeowners on that transformer and told them to call with a list of damages.
peter d
Senior Member
- Location
- New England
If I had to guess they were switching from a 2.4kV system to a 7.2kV system.
T
T.M.Haja Sahib
Guest
Putting surge arresters of appropriate rating at the service entrance at each power line to the subject home might have avoided the damages?
Not mandated by the code?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
I do not believe you stated that????:happyno:
No surge device is design to handle a long term surge, not even lightning arresters, next time you want to see some smoke hook up a surge device to a voltage of twice its rated value and see what happens, I have seen the damage to surge devices on long term over voltages.
Not going to happen.:happysad:
T
T.M.Haja Sahib
Guest
You are right and I know it already.
Let the surge arresters sacrifice in an effort to save the equipments inside the home.
My question is such a sacrifice effective?
Let the surge arresters sacrifice in an effort to save the equipments inside the home.
My question is such a sacrifice effective?
They are installed on every pot.
T
T.M.Haja Sahib
Guest
On the LV side also?
They aren't mandated by your countries electrical code?
T
T.M.Haja Sahib
Guest
Only on the HV side because secondary side distribution neutral is solidly grounded here also.
Then I believe you have answered your own question...:roll:
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