Col do you have a meter? and I really hope you live at the end of the line somewhere.
Urgent, need advice please. What's the difference between 1, 2 and 3 phase power?
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Col do you have a meter? and I really hope you live at the end of the line somewhere.
Of course I refer to Victoria only. Heavens knows how fast some hydro alternator is spinning
Of course I refer to Victoria only. Heavens knows how fast some hydro alternator is spinning
You can come to my place with your own meter, just let me do some adjustments first and I'll make sure it reads exactly 230V across all three phases.
I wonder, how do you prepare a left knacker, roast bbq any ideas.
Rob, if your at the FCD next Sunday and I get my donk back in next week and you see the floride come over for a chat about electrical automation or what ever if you get tired of car talk.
hi all its an interesting topic for sure.
a clever friend of mine used to star-wire his three-phase motors to run them on single phase by first starting each squirrel cage of the 3-phase motor spinning one by one. i doubt if anyone here has tried it?
Another thing is there are kits which allow 3-phase to run on single-phase 240 volt.
best of luck
Timbo
205-GTI
a clever friend of mine used to star-wire his three-phase motors to run them on single phase by first starting each squirrel cage of the 3-phase motor spinning one by one. i doubt if anyone here has tried it?
Another thing is there are kits which allow 3-phase to run on single-phase 240 volt.
best of luck
Timbo
205-GTI
Glad that's over, Col, Rob, Roger. Three of natures gentlemen that would do anything to help one another or a frogger in trouble, so no worries, my good friends, who all know their electrickery, though who knows what one might encounter in the industrial and farm jungles of Australia..
I bet Col gets to see some weird and wonderful wiring in Tassie, after all he has looked at the Lonnie house,:headbang: and that is much different to the wiring here at my home, but mine would frighten most with it's post war mixture of wiring.. One of the mates at work was trained as an electrician in South Africa, and he was shocked at the way housing cable was laid in Australia, theirs had to run on cotton reel rollers at set intervals for a start and secured and separate.
Interesting to hear about the higher supply voltage and its effect upon meters, Rob. I've heard of people installing voltage ? regulation equipment to prevent that. I take it that such equipment would have to be installed before the meter to regulate supply.
Anyone familiar with that type of installation, and we have a smart meter too, that I would have rather not been installed but, it has.
Regards.
Ken
though who knows what one might encounter in the industrial and farm jungles of Australia..I bet Col gets to see some weird and wonderful wiring in Tassie, after all he has looked at the Lonnie house,:headbang: and that is much different to the wiring here at my home, but mine would frighten most with it's post war mixture of wiring.. One of the mates at work was trained as an electrician in South Africa, and he was shocked at the way housing cable was laid in Australia, theirs had to run on cotton reel rollers at set intervals for a start and secured and separate.
Interesting to hear about the higher supply voltage and its effect upon meters, Rob. I've heard of people installing voltage ? regulation equipment to prevent that. I take it that such equipment would have to be installed before the meter to regulate supply.
Anyone familiar with that type of installation, and we have a smart meter too, that I would have rather not been installed but, it has.
Regards.
Ken
Both 240v tig and stick units will be adequate for auto work, as your MIG is. Welders are fairly cheap as you know, and when I had our metal workshop a few years ago I bought single phase 240v 'Chinese cheepies' for general jobbing and on site work, and only went to three phase for our structural production work. They lasted well by the way.
Ummm...
That was a little more than I expected, guys. Not sure I comprehended more than the rudiments.
Gero has some odd issues with power. Household power typically measures between 245 and 250v and standard 240v light globes don't last long. If one roots around the 250v globes can be found.
I suspect that the "500v" the sparkie measured at the shed were the 2 phases.
It was the local power company who said that they would need to install a power transformer at the front of the house and their quote was "upwards of fifty thousand." Given that the main substation is a mere 2kms from our place and we'll be in a semi rural area that all seems a tad odd.
Thanks again
P
That was a little more than I expected, guys. Not sure I comprehended more than the rudiments.
Gero has some odd issues with power. Household power typically measures between 245 and 250v and standard 240v light globes don't last long. If one roots around the 250v globes can be found.
I suspect that the "500v" the sparkie measured at the shed were the 2 phases.
It was the local power company who said that they would need to install a power transformer at the front of the house and their quote was "upwards of fifty thousand." Given that the main substation is a mere 2kms from our place and we'll be in a semi rural area that all seems a tad odd.
Thanks again
P
OK, I've had this topic discussed tonight at dinner between a dozen sparkies and luckily a few older heads amongst us.
From what I learnt was that you are all correct in part but all missing something. As we are discussing a number of different systems and until we can get a diagram to explain each of them we are all none the wiser only more confused.
No one had pen or paper but in theory was said if you had two phases of 240V 180 degrees apart it would not make 480V as they are opposing each other therefore resultant would be 0V.(can someone do the calculations).
Whippets readings of voltages are the only plausible examples, for any of the systems mentioned, yes there is so called two phase systems but they are of two separate voltages taken from separate windings so a 240V and 480V single phase each with a neutral return to earth.
Please fell free to quote a dozen electrical mechanics wrong as who we really need to ask is a linesman.
Don't ask me to find any proof to back this all up now, just let me have a couple more shots of rakija so I can roll over and fall asleep as I've done 33 days with 10hr days straight with only one day off in that time and I'm getting sick of this power station and really want to go home next week.
From what I learnt was that you are all correct in part but all missing something. As we are discussing a number of different systems and until we can get a diagram to explain each of them we are all none the wiser only more confused.
No one had pen or paper but in theory was said if you had two phases of 240V 180 degrees apart it would not make 480V as they are opposing each other therefore resultant would be 0V.(can someone do the calculations).
Whippets readings of voltages are the only plausible examples, for any of the systems mentioned, yes there is so called two phase systems but they are of two separate voltages taken from separate windings so a 240V and 480V single phase each with a neutral return to earth.
Please fell free to quote a dozen electrical mechanics wrong as who we really need to ask is a linesman.
Don't ask me to find any proof to back this all up now, just let me have a couple more shots of rakija so I can roll over and fall asleep as I've done 33 days with 10hr days straight with only one day off in that time and I'm getting sick of this power station and really want to go home next week.
Australian Standard
I was only quoting what the Australian Standard says.
You even backed that up with the PDF file that you provided Rob.
I was only quoting what the Australian Standard says.
You even backed that up with the PDF file that you provided Rob.
with a 40v - 50v of acceptable limit in most States, the 'standard/s' do indeed appear to be rather nominal!
for the record, when i stick the DMM probes into my NSW wall socket, it read 248v.
for the record, when i stick the DMM probes into my NSW wall socket, it read 248v.
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Wrong Alexander, and Rob should know better as well. When it comes to cable selection, volt drop, fault loop impedance and so on, and so on it is very important that the regs state 230V 400V, any calculations need to be correct. Actual voltage supplied is irrelevant, the numbers are given for calculations in maths and physics, some of us enjoyed this at trade school even if we indulged on the weekends or every night.
how can the standard voltage, and calculations based thereon, be so precisely important, if the actual voltage can vary in a 50v range?
personally, and not speaking as an engineer, sparky, or anything similar, if I was specifying hardware like cabling, i reckon i would be looking at the maximum voltage, rather than a nominal one emanating from canberra.
personally, and not speaking as an engineer, sparky, or anything similar, if I was specifying hardware like cabling, i reckon i would be looking at the maximum voltage, rather than a nominal one emanating from canberra.
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Because cables are expensive, so you need to work out the smallest possible cable size to handle the voltage, current and conditions it's run in.
yes, that i understand, but if your goal is to minimise cable cost, then it is the maximum voltage and current you have to consider, not the standard, right?
You are confusing three variables.
First, the supply voltage variation. This is defined by the Electricity Regulator. It is set within a high and low figure. From experience the electricity tends to be the high side of the ideal voltage.
Second, distribution voltage drop. That is voltage drop due to resistance of the copper/aluminium in the street cables.The electricity supplier factors the voltage drop into the distribution network and the lead in cable to the premises. In a perfect world the voltage at the service fuses will remain within the regulators defined voltage range whilst the consumer is drawing the maximum load as set by the fusible links. Then of course there are MD calcs which I won't even start to discuss.
Third voltage drop within the premises caused by copper losses. I recall 2% voltage drop on any circuit was the maximum allowable design parameter, but I stand to be corrected. Essentially the losses in the cables show up as heat and the 2% is set as a balance between safe temperature rise and correct functioning of the load equipment. If a MIMS cable (pyrotenax) was used the allowable voltage drop was allowed to be much more due to better heat handling. That is why pyro was always used a sub-mains from HV substations.
As to the your consultation with your experts about the two phase 480 volt supply. Rethink your theory please. The supply is derived from a centre tapped 480 volt transformer. The CT being the neutral and either end being the phases.
At any instant in time each end of the windings are 180degrees out of phase in voltage. Ie on a voltage peak of the sine wave. On the next mains half cycle it's the same with the peaks inverted.
The transformer phase inversion matches the sine wave half-cycle alternation.
This situation is quite different to the three phase scenario. Because the phase angle is 180 degrees and not 120 degrees.
See the mud map :wink2:
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Hi Guys,
out of interest, how does the two phase motor that are 180degrees apart work. Surely it can't work on the same principle as a 3phase motor (the rotor would end up locked in a stalled position).
So they must be single phase motors running across the 2phases and running at twice the voltage, half the current. There must be two lots of windings inside the motor two ? run in parallel for 240volts, series for 480volts.
seeya,
Shane L.
out of interest, how does the two phase motor that are 180degrees apart work. Surely it can't work on the same principle as a 3phase motor (the rotor would end up locked in a stalled position).
So they must be single phase motors running across the 2phases and running at twice the voltage, half the current. There must be two lots of windings inside the motor two ? run in parallel for 240volts, series for 480volts.
seeya,
Shane L.
Correct on all counts, Shane. Except that it is arguable whether you would say there were two lots of windings or one lot of windings with appropriate tappings.
Roger
Roger
Generally motors aren't two phase.
If 2 phase 240 v is volts is available the motor is connected usually connected across the phases as single phase 480 volt motor. There is no benefit of two phases for rotating equipment. But the 480v supply allows more power to be drawn and thus more powerful motors.
480volts also allows big arc welders to used. But that is transformer and able to easily "tapped".
Rob, Pyro? Your showing your age, it hasn't been used in decades. I was lucky to use it a half dozen times when I was a boy, but not since.
Voltage is pointless, current is the factor when calculating cable size, it doesn't matter if its 236V or 258V it's the load or current which will define anything.
Voltage is pointless, current is the factor when calculating cable size, it doesn't matter if its 236V or 258V it's the load or current which will define anything.
Voltage DROP & copper losses
You know ohm's law and all that irrelevant crap?
Have you ever heard of cable de-rating?
They way cable is specified by the percentage voltage drop, ie the with full load current flowing in the cable. The max voltage drop across the cable should be no more than 2% of the applied voltage.
http://www.ecables.com.au/?page_id=85
OK so the maximum allowable is 5%. I always designed at 2% because the equipment we used was quite voltage critical.
Read the regs....