bulbs blowing help please...

[rumrunner]

Cheers pall,excellent answer ,top marks, i think i am begining to understand it a bit better now,still dont know why his bulbs exploded ,maybee he should have used an hf digital ballast.
enjoy your afternoon and your weekend on the bow,you deserve it after those answers
atvbitwww

 

[Bane]

Didn't he do well.

 

[wayne]

i think an applause is in order for both rr &shakey ,now im going for a beer and some migraine tablets

 

[rumrunner]

[

So a harmonic will tend to INCREASE the amount of induced EMF's, both linear and non-linear, with the effect that with a step up, the harmonic effect would be increased (i think)

If the above is so ,then a "swinging ground" ,which as far as i can tell is the partial breakdown of the insulation in the transformer ,whitch induces more emf ,due to the harmonics caused by the rapid decline in the voltage in the inductive circuit,momentarally,
which then flows around the circuit and blows the bulbs(weakest part of circuit)

have i got it right this time shaker

 

[MacSparky]

Wow!! I wish my wife had this sort of knowledge........i'd probably listen more
Fantastic posts guys...loving it

 

[Shakey]

[

So a harmonic will tend to INCREASE the amount of induced EMF's, both linear and non-linear, with the effect that with a step up, the harmonic effect would be increased (i think)

If the above is so ,then a "swinging ground" ,which as far as i can tell is the partial breakdown of the insulation in the transformer ,whitch induces more emf ,due to the harmonics caused by the rapid decline in the voltage in the inductive circuit,momentarally,
which then flows around the circuit and blows the bulbs(weakest part of circuit)

have i got it right this time shaker

sort of, but the bulbs blowing is an effect of something happening momentarily rather than permanently, and i ten to think of (even a partial) breakdown of the insualtion as a permanent thing.

A fault to earth on the HV side would cause a power frequency fault voltage (yes, rapid collapse of fields, harmonics etc) this would cause a power frequency stress voltage on the LV side (because its a massive step down) which would certainly pop bulbs

but as i said, i tend to think of this as a 'one off' event rather than an occasional event, which is what i think that chap is describing.

although you could use the same analogies for faulty connections etc on the HV side causing harmonics on the LV side. And remember, we are stepping down, so....

the induced voltage would be stepped down, therfore the current is stepped up (because power out = power in as you well know!!!)

but if that is a harmonic current, then that PRODUCES a harmonic voltage, which of course, thanks to mister Lenz could be great in magnitude, AND non-linear (ie a voltage spike)

job done

off to the 'bow have fun guys

and cheers Rum, its good to talk!

 

[rumrunner]

Yeah thanks Shakey i enjoyed that ,bit more pain than a visit to miss whiplash ,but 200 quid cheaper,we should do it more often,

i agree that even a partial breakdown of the transformer insulation would be a perminent
situation

now is it possable that a factory ,say using some inverters or machines which are turned off quickly puts the harmonics on the line
if it is harmonics that are to blame anyway

ive got a feeling we will never know ,it might not ever happen again ,i doubt if the electric board will commit huge resorces to investigate the matter,its a shame i dont like not knowing whats wrong with something

enjoy your holiday ,all the vb

 

[Shakey]

Yeah thanks Shakey i enjoyed that ,bit more pain than a visit to miss whiplash ,but 200 quid cheaper,we should do it more often,

i agree that even a partial breakdown of the transformer insulation would be a perminent
situation

now is it possable that a factory ,say using some inverters or machines which are turned off quickly puts the harmonics on the line
if it is harmonics that are to blame anyway

ive got a feeling we will never know ,it might not ever happen again ,i doubt if the electric board will commit huge resorces to investigate the matter,its a shame i dont like not knowing whats wrong with something

enjoy your holiday ,all the vb

i dont think the factory would cause the problem elsewhere, because:

they wouldnt 'put harmonics on the line'

the harmonic current would be caused by the machines, in the cables carrying current TO the machines. And rememebr the harmonic voltages are a PRODUCT of the harmonic current not the other way around, so i dont think the harmonic would travel 'back up' the line and then go elsewhere

its only my opinoin though, and i make most of this stuff up anyway!

have a good one Rum

 

[rumrunner]

YouTube - Lenz's Law Demo 2 heres a short vid i found whilst researching lens law ,i think it explains it almost as well as shake
atvbitwww

YouTube - Lenz's Law Demo 2 heres a short vid i found whilst researching lens law ,i think it explains it almost as well as shake