lee wrote on Jan 30^th, 2018 at 8:07pm:


Let me think.. P = VI   -> so if V is little, then I increases to maintain V?

stunspore wrote on Jan 30^th, 2018 at 8:09pm:


"Depends on what kind of load it is. There are two types of load: Resistive and Inductive.

In case of resistive load, low voltage will lead to less current and so it will not get damaged. But at high voltage the current will increase and it can get burnt.

In case of inductive load (any kind of appliance with motor like Air Conditioner, Washing Machine, Refrigerator, etc), at low voltage it will try to pull more current just to run and this can lead to burning of the motor. Even high voltage can cause damage to inductive load. Usually such appliances have operating voltage range at which they can be operated."

Comment in -

https://www.quora.com/What-happens-when-you-supply-too-much-or-too-little-voltag...

lee wrote on Jan 30^th, 2018 at 8:14pm:


The vast majority of these appliances use induction motors. These motors will draw most current until the rotor achieves synchronous speed. At low voltage synchronous speed may not be reached and excess current will prevail. All of these motors however employ thermal overload protection as outlined in Australian standard AS 60034. It is unlikely that slow motors caused the blackouts.

The reality is as already pointed out is that the load demand exceeded the maximum allowed by the distribution network and the breakers tripped as a result.

Point the finger at the owners of the infrastructure who've had over twenty years to bring it up to scratch.

There there croc don't feel too bad. You can lose them all. In fact you DO.

You destroy your credibility when you repeatedly unsuccessfully try to put down the person instead of concentrating on the topic.

From experience one knows you are very sensitive to any criticism and so you think others are just as sensitive.

But some are almost immune as criticism and insults are like pouring water on a duck's back. It is known as developing a thick skin.

The simple TRUTH is that if the Vic power source and cables had been adequate to supply the load then the fuse would not have blown.

The fuse does not blow when the load is within spec - only when the load exceeds spec.

So the Vic system supplying the blackout area is simply too small to carry the load and so the fuse obediently did what it is designed to do - blew to protect the inadequate supply system from excessive current.

Exactly why the supply system is too small is another question altogether. Is it a result of the private operator under designing ? Is it a result of insufficient generating capacity after closing Hazelwood ?

You can imagine how nervious this must be making SA with its unstable erratic Secondary Power renewable rubbish which only works on every other day as SA is totally dependent on the link to the Primary Power coal stations in Victoria.

So if Victoria fails then it takes SA down with it!!!!!

Tasmania also has a link to Victoria but Tasmania has lots of Primary Power from hydro so unless they run out of water they are self sufficient.

SA is indeed the canary in the coal mine that warns the rest of Australia about the futility of renewable rubbish Greeny dreams.

juliar wrote on Jan 31^st, 2018 at 6:13am:


I don't feel too bad at all. I just find your abject stupidity rather entertaining.

Oh my Goodness the political correct croc is offended - again.

never mind croc have a good day anyway.

croc I am looking forward to the time when you develop a thicker skin and get over being offended by trivial things and start actually arguing the topic and forgetting about trying to put the person down.

To clarify - a fuse blows because there is too much current flowing thru it.

The fuse size is set to ensure the current flowing thru it doesn't cause a serious voltage drop at the appliance end.

The max current is set by the size of the supply and the connecting cables.

So if the current is below max then the fuse will not blow and the supply can handle it.

If the current rises above the max current the supply can handle then the fuse trips to protect the supply which is unable to supply that amount of current.

So it is pretty obvious that the supply was too small to supply the current during the heat wave to that blackout area otherwise the fuse would not have blown.

As far as the fuse is concerned it is interested ONLY in the current flowing thru it and whether the current is lagging, in phase, or leading the voltage is of no interest to the fuse.

A lagging current is a nuisance as it increases the load on the supply as the actual current flowing becomes the vector sum of the in phase and out of phase currents. Capacitive loads are sometimes used to pull the power factor back towards unity to reduce the current load on the supply.

The real situation is more complex as the supply is 3 phase so the problems are multiplied by 3 at least.

The further complication is the private operator who made have under designed the cables.

As Hazelwood Primary Power was a huge energy source that could have handled the load with one hand tied behind its back then its removal must leave the Vic power network much more vulnerable particularly as it has to supply SA as well when SA's shoddy Secondary Power network falls over.

So it is plausible Vic may be running short on Primary Power coal generating capacity.