FREQUENCY-50Hz IN INDIA WHY???

probably because it was part of The British Empire and Britain used 50Hz. India also uses mains plugs and sockets of the type that used to be used in the Britain.

Why would you want to?

| why is the frequency is 50 hz in india...can we use some other | frequency?if so what is the range and what will be the effect in | present power system if we change the frequency as you suggest?

That's because you guys kicked the Brits out _after_ you got electricity, rather than _before_ like the Americans did.

Feel free to change it to 60 Hz or some other frequency, if you want.

60 Hz should work fine with most of the 50 Hz transformers, and even give you 20% more voltage range if the insulation had been overrated (don't count on it).

But who would pay for it?

Seriously, you're stuck with this legacy of the British Empire unless you want to expend some HUGE costs retrofitting. In the very early years of electric power in America and Europe, there was quite a mix of not only frequency, but also voltage. One of my grandfathers was an electrician in the 1920's to 1940's (he switched over to the cable TV business in the

1950's and if he were alive and kicking today I'm sure he'd be into the internet) and told me stories of some of the electrical systems he worked on that ran on 16 Hz and 25 Hz that primarily served coal mines, but in a couple cases also served the local town. At least all the small weird electric power companies that picked their own voltage and frequency long ago have died off. I've heard of 33 Hz, 40 Hz, and even one that supplied 500 volts directly to homes (I wouldn't be all that concerned about such voltage if it were the standard today, but long ago, electricity was so much more dangerous due to poor practices of the age).

Consider the case of two countries that have mixed frequency power. They can't readily change even that, despite having substantial motivation to do so (Japan and Brazil as far as I know).

You also have 220, 230, or 240 volts per the British Empire. But that is probably to your benefit (except for incandescent lights, but fluorescent lights work great on that voltage, not needing the special starters we have to use in 120 volt land). If you have some really big appliances, like a big oven or kiln, you might have three phase power available and can run things on 380, 400, or 415 volts and save on expensive copper wire.

Still, I'd be curious what kind of electrical system India would have chosen had it never been under the control of the British Empire or any other external influences. Would they have chosen one of the existing systems or gone with something entirely different?

I've seen a turn-of-last-century 550 volt, 40 Hz generator, which supplied power for a wool mill.

I've kind of wondered if we had to design an electrical system completely from scratch (no need to be backward compatible with anything), how should it be done? Voltages, frequencies? Any advantage to anything strange like 5 phase power (I doubt it, but imagine, we'd be talking about transformers wired as pentagon, star or "real star" configurations)

On Sat, 5 Apr 2008 02:46:23 +0000 (UTC) Michael Moroney wrote: | snipped-for-privacy@ipal.net writes: | |>ago have died off. I've heard of 33 Hz, 40 Hz, and even one that supplied |>500 volts directly to homes (I wouldn't be all that concerned about such |>voltage if it were the standard today, but long ago, electricity was so |>much more dangerous due to poor practices of the age). | | I've seen a turn-of-last-century 550 volt, 40 Hz generator, which supplied | power for a wool mill. | |>Still, I'd be curious what kind of electrical system India would have |>chosen had it never been under the control of the British Empire or any |>other external influences. Would they have chosen one of the existing |>systems or gone with something entirely different? | | I've kind of wondered if we had to design an electrical system completely | from scratch (no need to be backward compatible with anything), how should | it be done? Voltages, frequencies? Any advantage to anything strange | like 5 phase power (I doubt it, but imagine, we'd be talking about | transformers wired as pentagon, star or "real star" configurations)

No advantage to 5 phase. 3 phase does the job. 2 phase could do the job. More phases can be derived from existing phases when supplyed by 3 phase or

2 phase (90 degree) power if the load needs more.

If there was no cost of conversion (e.g. I could go back in time and just make the decision), I might choose a system that requires loads to make use of line-to-line connections instead of line-to-neutral connections. They would get the higher voltage that way, while the line-to-ground hazardous voltage would be less. The particular voltage I would pick for line-to-line is 288 volts. It would be supplied by 3-wire single phase with 144 volts line-to-ground or three phase with 166 volts line-to-ground. The Edison light base would be prohibited for "high voltage" use and restrict to low voltage lighting, only, constructed with step down transformers at 12 volts much as low voltage lighting is done today. Industrial voltage would be

499/288 but might get called 500/288. Notice the last 2 digits of every voltage happens to come out as 2 of the same.

I had suggested 72 Hz when I mentioned this in a previous posting. A few responses suggested that transmission of this over long distances would be less efficient. Today, we have the technology to do such transmission in DC (if only Edison could see that). We can also convert DC voltages more readily than we could many decades ago (pulse pumping a capacitor or stack of capacitors).

As for voltages and frequencies- a fresh start could well result in 240V (+/-) and still in the 50 to 60 Hz range for general applications. That is my guess. As for frequency, either choice is a compromise between different requirements - a lower frequency has advantages for transmission and motors but results in larger machines and can be annoying for lighting. A higher frequency results in smaller machines (e.g. 400 Hz for aircraft) but is more limited for transmission.

In general there is generally no gain (an added complications) going beyond 3 phase except in particular cases such as some rectifier supplies at

6 or 12 phases (which are derived from 3 phase) as these result in the elimination of some of the lower harmonics giving a smoother DC without filters.

So we would probably end up with something similar to what we have which is based on a lot of experimentation in the past. Optimization based on experience and changes in the system as needs changed (e.g. dropping 25Hz and going to 50 or 60 Hz when the change in industry favoured multiple smaller motors rather than a single large motor driving many loads with a belt system).

Note that much more of the world uses the UK based system than the US based system- including countries that were not part of the British Empire- in those days, the Brits may have had better salesmen world wide.

Anyhow, it is all "what if" and a fresh start would involve international committees trying to come to a compromise -while the candle industry thrived:).

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72 Hz is not bad but even for moderately long lines, it will lead to more problems than 60 Hz- 20% higher series reactance and shunt susceptance does have an effect - a 200mile line at 72 Hz would have the parameters of a 240mile line at 60 Hz. or a 288 mile line at 50Hz. This can make a difference in charging current and voltage regulation. The sweet spot still appears to be in the 50-60Hz range for most applications. DC is nice but is generally not economical for such distances and definitely not for a grid. As for pulse pumping a capacitor stack-probably unfeasible at the power and voltage levels of a modern HVDC line and inversion is another problem.

| 72 Hz is not bad but even for moderately long lines, it will lead to more | problems than 60 Hz- 20% higher series reactance and shunt susceptance does | have an effect - a 200mile line at 72 Hz would have the parameters of a | 240mile line at 60 Hz. or a 288 mile line at 50Hz. This can make a | difference in charging current and voltage regulation. The sweet spot still | appears to be in the 50-60Hz range for most applications. DC is nice but is | generally not economical for such distances and definitely not for a grid. | As for pulse pumping a capacitor stack-probably unfeasible at the power and | voltage levels of a modern HVDC line and inversion is another problem.

Why not just invert the same way (capacitor stack) but logically in reverse? Just switch the DC on and off at a pulse rate to simulate the sine wave and charge the capacitors accordingly. The sine wave rate and the switching rate should be very far apart. Of course, doing this at utility power levels is still a big issue. But I see this idea as being feasible to do conversion not only to DC but also from DC. And it could even do polyphase directly between different AC frequencies with no intervening DC. Since polyphase power has the character that the power level is constant across the whole wave cycle, its just a matter of doing the right amount of switching between the phases fast enough to level out the power transfer.

| As for voltages and frequencies- a fresh start could well result in 240V | (+/-) and still in the 50 to 60 Hz range for general applications. That is | my guess. As for frequency, either choice is a compromise between different | requirements - a lower frequency has advantages for transmission and motors | but results in larger machines and can be annoying for lighting. A higher | frequency results in smaller machines (e.g. 400 Hz for aircraft) but is | more limited for transmission.

I've been convinced since that 72 Hz proposal that 60 Hz would be better. But I still like my 288 volt idea. But making the change today in the real world could be done on a very gradual basis using 240 volts as the target. Why not wire fluorescent (not screw in CFLs) light fixtures at

240 volts (line to line in the USA)? NEC 210.6(A)(1) would have to be changed to do this.

| In general there is generally no gain (an added complications) going | beyond 3 phase except in particular cases such as some rectifier supplies at | 6 or 12 phases (which are derived from 3 phase) as these result in the | elimination of some of the lower harmonics giving a smoother DC without | filters.

That would seem like a possibly good reason to go with more phases. It would depend on the balance of cost between having the extra components (additional transformers to derive other phases and more rectifiers) and the reduced components (fewer capacitors to smooth it out).

| So we would probably end up with something similar to what we have which is | based on a lot of experimentation in the past. Optimization based on | experience and changes in the system as needs changed (e.g. dropping 25Hz | and going to 50 or 60 Hz when the change in industry favoured multiple | smaller motors rather than a single large motor driving many loads with a | belt system). | | Note that much more of the world uses the UK based system than the US based | system- including countries that were not part of the British Empire- in | those days, the Brits may have had better salesmen world wide. | | Anyhow, it is all "what if" and a fresh start would involve international | committees trying to come to a compromise -while the candle industry | thrived:).

If all appliances were required to accept 220-240 volts, and were required to accept either or neither wire being grounded (as is the case in Germany), then they should work anywhere in the world (as long as a 240 volt circuit is available in North America). Japan would be the exception unless the voltage range goes 200-240.

I still think the USA would benefit by getting NEC 210.6(A)(1-2) out of the way and letting more things use 240 volts (even if the outlets have that sleepy face look).

The first generating stations at Niagara Falls produced 25 Hz AC, and it supplied consumers in some of the surrounding area. My father tells (well, told) a story about consumers having to have all of their frequency-sensitive appliances repaired or replaced when 60 Hz took over. This was in the Hamilton-Niagara Falls Ontario area.

Clocks with synchronous motors and anything with an induction motor would have required motor replacement. 25 Hz transformers have more iron than they need for 60 Hz, but do they have more eddy current losses?

Dave

There's been some discussion of this on the antique radio group. Seems transformer radios in that market were rated 25-40Hz.

Since the bulk of electrical energy is not rectified-going to more phases doesn't make sense. For rectification- then it may be worth while (and certainly has been considered so in the past) and it is simple to go from 3 to 6 or 12 phase where desired (for 6 phase consider secondaries center tapped and the neutral at the tap so that now you have 6 line to neutral voltages, 60 degrees apart. For 12 phase two such transformers but one connected Y on the primary and the other delta on the primary- getting a 30 degree shift). A variation of this is used for HVDC to provide some smoothing but filters are still needed.

Your pulsed capacitor idea may be fine but the problem is switching, particularly at high voltage and current levels may simply be unfeasible particularly at higher frequencies. A wee bit of inductance as will always be there and DC currents of the order of 1-2KA don't switch worth a damn. If switching of DC was easier then it might open up the possibility of a HVDC grid- still need conversion back to AC as 500KV DC in your house is a bit impractical. The power level being constant is really a matter of balanced loads- you generate and deliver what the load needs whether it is balanced or not. It really would have nothing, that I can see, to do with switching. --

Don Kelly snipped-for-privacy@shawcross.ca remove the X to answer

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Eddy currents losses per unit volume depend on (Bf)^2 -a bit of a swap- and hysteresis losses depend roughly on nearly the same factors but there would be a larger volume of iron so core losses of a 25Hz transformer would be larger at 60 Hz. --

Don Kelly snipped-for-privacy@shawcross.ca remove the X to answer

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| Eddy currents losses per unit volume depend on (Bf)^2 -a bit of a swap- and | hysteresis losses depend roughly on nearly the same factors but there would | be a larger volume of iron so core losses of a 25Hz transformer would be | larger at 60 Hz. --

So, basically, you need to design the core to avoid saturation (needs to be big enough) and minimize losses (don't make it larger than needed). Those transformers rated for 50-60 Hz are a bit less desireable when you know you only need 60 Hz.

Britain used a lot of frequencies, including a large region at 40 Hz. Anyone interested in this should check out the book "Networks of Power" by Thomas Hughes. British manufacturers standardized on 50 Hz to improve access to the European export market.

I'd be pretty confident that there must have been some 40 Hz power in India.

Bill

I figured that. I really just wanted an excuse to mention silliness like (real) star and pentagon connected power system. But I do wonder: Were oddball phases like 5 phase, or any other non-multiple of 3 or 2 ever used? I know 90 degree two phase was used in early days.

Also, if you really ever had to, you could generate oddball polyphase power using the same idea as behind a Scott-T transformer setup. You may need some really oddball multiwinding transformers with taps at odd ratios to do so, however!

One thing I might do is have utilities offer voltages at rations of sqrt(3):1 to allow motors to be used on either of two voltages with just delta-wye reconfiguration. For example, offer 208Y/120V, 360Y/208V,

624Y/360V. A "208V" motor could be used on the first service wired in delta, or on the second service wired wye. A big "360V" motor would work from either the second or third service.

Phil mentioned using the US 240V residential power for everything, the transformer CT just a safety ground. One disadvantage to that is the need for double pole switches (and associated wiring) for everything, or else live with the fact that every lamp socket or whatever is "hot" even if off. Imagine three-way switches if they had to be double pole as well!

| Phil mentioned using the US 240V residential power for everything, the | transformer CT just a safety ground. One disadvantage to that is the need | for double pole switches (and associated wiring) for everything, or else | live with the fact that every lamp socket or whatever is "hot" even if | off. Imagine three-way switches if they had to be double pole as well!

Within the home, lights would be on a reduced voltage derived from the service voltage. The thought I had was to use 12/24 volt transformers in the split phase style.

The switch issue is real. But a double pole normal switch is no big deal and would probably be just a few pennies more when that's what everyone uses. A single pole switch could be used on low voltage. But the runs through the switch would have more voltage drop and so long runs would be an issue.

The system I suggested would be less practical in the past than it would be today. Today we could make more use of remote controlled switching so the long wire runs would either be very thin wires (for control signal only, not power), or no wires at all (IR, RF, US, etc).

Switching to the 288 volts I suggested is a fantasy. Switching to 240 volts is a plausible reality because it's already available to make a very smooth transition. Once everything runs from 240 volts without regard to whether any conductor is grounded, then any need to supply this in the form of three phase could be done with 138.5 volts L-N (note that this is half of 277). Computers and some other electronics can be switched over now (though there is a lack of plug-in surge protectors with the correct components for the type of system in North America). Once it starts, and especially once a lot of 240 volt outlets become common, more electronics will be either 240 only (probably 220-240) or wide range (100-240).

12/24V seems to be going contrary to your reasons for considering 240V over 120V. Conductor costs/watt would be higher. As well, voltage drops in the 2-3V range would be significant. As for remote switching- the switching is no easier but it would cost as much to pull in control wiring as it would be to pull in the regular wiring. This or RF,IR etc, simply adds cost and complexity- violating the KISS principle.

|> | Phil mentioned using the US 240V residential power for everything, the |> | transformer CT just a safety ground. One disadvantage to that is the |> need |> | for double pole switches (and associated wiring) for everything, or else |> | live with the fact that every lamp socket or whatever is "hot" even if |> | off. Imagine three-way switches if they had to be double pole as well! |>

|> Within the home, lights would be on a reduced voltage derived from the |> service voltage. The thought I had was to use 12/24 volt transformers |> in the split phase style. |>

|> The switch issue is real. But a double pole normal switch is no big deal |> and would probably be just a few pennies more when that's what everyone |> uses. A single pole switch could be used on low voltage. But the runs |> through the switch would have more voltage drop and so long runs would be |> an issue. |>

|> The system I suggested would be less practical in the past than it would |> be today. Today we could make more use of remote controlled switching |> so the long wire runs would either be very thin wires (for control signal |> only, not power), or no wires at all (IR, RF, US, etc). | | 12/24V seems to be going contrary to your reasons for considering 240V over | 120V. Conductor costs/watt would be higher. As well, voltage drops in the | 2-3V range would be significant. As for remote switching- the switching is | no easier but it would cost as much to pull in control wiring as it would be | to pull in the regular wiring. This or RF,IR etc, simply adds cost and | complexity- violating the KISS principle.

The closer the 240->12 transformer is to the light, the less those losses are in the wiring. The floor of the loss is then that of the transformer. If sized right, it keeps it to a fair minimum. That loss should be overcome by the gains in low voltage halogen over conventional incandescent.

I do agree, this adds complexity and backs off from KISS. But I think the gains would be worth the added complexity. Eventually it would be effectively simple because at some point all light fixtures would come with everything already built in (transformer and control receiver/switching). I just hope the control protocol becomes an open standard so you can mix any control transmitter you desire.

| *"Anyhow, it is all "what if" and a fresh start would involve | international | committees trying to come to a compromise -while the candle industry | thrived:). "*

We'd end up with system with 195.3 volts, 54.77 Hz, 5 phases, 2 neutrals, and who knows what for ground.

| Haha, there still might be money in that. :)

Lots!