might need help up here...

[Pootnaigle]

Umm matter of fact I did.

[dooghi]

Did you say ummmmmmmSorry Poot I just had to say it. LOL

[MI-Lineman]

Right this is the story. when wiring a 3 phase transformer into a factory with lathes. You have to have the lights and the lathes on a different phase. Because both are 240 volts they will run off the same phase. BUT . When the lights ( floresent tubes) are on the same phase and the lathes are spinning. The lights flicker at the same speed.this leads to an optical illusion . Iit looks as if the lathes aren't moving........ There was a lot of accidents until they figured it out.



SO an irish man that new something. Nice one. !!!!!!

Here's a stupid question.....wouldn't the lathes in a factory be 3 phase so how would you separate the lights from the lathes??? Me confused??

[BigClive]

Here's a stupid question.....wouldn't the lathes in a factory be 3 phase so how would you separate the lights from the lathes??? Me confused??

The problem arose with the lights being on a single phase causing a stroboscopic effect on any equipment that had mains synchronous motors whether they were single or three phase. Traditional fluorescent lights are actually extinguished for part of the cycle where the mains passes through the zero crossing point and it caused enough of a strobe effect to cause spinning parts to appear stationary or moving slowly if the field was slipping on a loaded motor.

The answer was to spread the lighting across all three phases so that they passed through the zero crossing points of the sinewave at different times, thus giving continuous light.

[MI-Lineman]

The problem arose with the lights being on a single phase causing a stroboscopic effect on any equipment that had mains synchronous motors whether they were single or three phase. Traditional fluorescent lights are actually extinguished for part of the cycle where the mains passes through the zero crossing point and it caused enough of a strobe effect to cause spinning parts to appear stationary or moving slowly if the field was slipping on a loaded motor.

The answer was to spread the lighting across all three phases so that they passed through the zero crossing points of the sinewave at different times, thus giving continuous light.

Yeah I got your answer! Just curious if I misunderstood what he was sayin? Any small chop shop around here has 3 phase lathes on a single phase srvc let alone the big 3 phase factories havin 3 phase lathes?

Anyway, I'm curious about this topic cuz here stuff like that is overlooked and automatically shoved aside as customer problems and I always need to know the real reason for me self. For instance we have a local electrician who's parents house has blinkin lights. I guess we have had several srvc workers respond to find good steady voltage and label it a customer problem but the electrician says he gets a good voltage read but one leg (120v mind you) he reads 60 hertz like he should but the other leg can be anywhere from 100 to 300 hertz at any time and the lights blink pretty bad? I asked to be sent there but the boss doesn't seem to wanna put anymore time in it? I know his parents are fed off of a single phase line on their own transformer not to far from a recently (last year or 2) installed isolator to drop the voltage from 14.4 to 4.8? What I can't understand is why only one leg (always the same one to) is doin this and what's causing it? I've heard incandescent lights can cause these issues too but on a single phase srvc to a house?

What you think Pluto or Ben??

[BigClive]

Checking the frequency is a bit odd, since it's pretty much going to be 60Hz. If it's jittering around and showing higher frequencies then that sounds like an arcing connection. Trouble is it'll arc and the lights will flicker for a while and then it'll heat up, abrade and work for ages again. One day you'll find the fault because it'll stick for a while. Personally I'd want to go and do a thorough check of all connections from the transformer to the residence to rule my side out. It could even be the transformer itself or further upline.

This is where power condition meters that log voltage continuously are useful, but they're REALLY expensive devices.

[MI-Lineman]

Yeah I'm thinkin connection cuz how would it be up line from the transformer and only one side (its wye BTW) be doin it? We have voltage recorders but the customers voltage is rock solid all the time even when the hertz is outta whack and the lights are blinkin?

Wish I could convince the co. to let me check it out and maybe I could send out a T-shirt to who ever got it right?

[reppy007]

Yeah I'm thinkin connection cuz how would it be up line from the transformer and only one side (its wye BTW) be doin it? We have voltage recorders but the customers voltage is rock solid all the time even when the hertz is outta whack and the lights are blinkin?

Wish I could convince the co. to let me check it out and maybe I could send out a T-shirt to who ever got it right?

Im ordering a few t-shirts from luckenback,Texas.Willie Nelsons favorite song,,,,,might fit BigClive pretty well............

[Pootnaigle]

Ummmmm if using a recording voltmeter it would prolly be best to hook up 2 one on the utility side and one on the customer side if there is a bobble it will tell you where to look.Back in the day we would put a bare finger on every connection to feel for heat. That was naturally outlawed and we were told to use a wax candle and if it melted the Connection was prolly hot and bad.There was a brand of breaker boxes that were known to cause a problem like you describe and it was called ZINSCO.Pitiful design.I once encountered a similar prollem and the secondary was open wire. Everything checked out fine on a Rec VM but the prollem persisted and an engineer told me in big words that I never heard before that the problem was caused by the open wire so we had it changed to cable and sho nuff it was all better.

[reppy007]

Ummmmm if using a recording voltmeter it would prolly be best to hook up 2 one on the utility side and one on the customer side if there is a bobble it will tell you where to look.Back in the day we would put a bare finger on every connection to feel for heat. That was naturally outlawed and we were told to use a wax candle and if it melted the Connection was prolly hot and bad.There was a brand of breaker boxes that were known to cause a problem like you describe and it was called ZINSCO.Pitiful design.I once encountered a similar prollem and the secondary was open wire. Everything checked out fine on a Rec VM but the prollem persisted and an engineer told me in big words that I never heard before that the problem was caused by the open wire so we had it changed to cable and sho nuff it was all better.

..........those Zinsco main breakers are hard to find.......a few years back i knew of a shop that had plenty.....100 bucks I believe..might have been 200......but when shooting trouble and saw a zinsco..........it usually was the breaker heating up............