Evidently the torque in the 50 Hz versions is greater than 1.2 x the torque in the 60 Hz versions. Maybe some further research along that line will help.

The inductive reactance of a circuit varies directly as the frequency?

There was a similar thread in CR4(thread number.....),hope somebody will give the thread number/title/date.

I suspect this is the one http://cr4.globalspec.com/thread/76754#comment836465

Yes. But who cares. And we discussed it before.

Both answers apply.

By the way, if you are in a 50 Hz country, that applies, and other outputs, like 55, 60 or even 400Hz (a legit generator frequency for airplanes) or any other simply does not apply, as if these did not even exist. Pointless, big time.

The reason is lack of load. If you load the system or tie it into an existing 50Hz grid as it spins up it will sync to 50Hz. The system is designed to deliver X watts and must consume Y units of fuel to do so. The turbine control system will not begin to cut back on the fuel until it exceeds 50Hz.

Check the minimum load specification on the unit, until you exceed that minimum load the system will be above 50Hz.

Thanks Regsoft. It was a great spin up for a layman. I like that skill set. Can you do it again explaining how the generator is tuned to the circuit it is powering and adjusts power output based on demand?

Gav

I don't have time to read the manual for this device but...

one way is to manually intervene and hold the system to near the frequency of the grid you are attaching to before letting the controller take over. While near grid frequency, when the phase error is low connect the generator to the load. Then allow the automatic control system to take over. The generator will transfer power to the system by essentially pulling the grid forward in phase as the automatic control system takes over. If you are not supplying enough power to the generator it will actually draw power from the grid It is important to match phase when closing into an existing grid or you may trip other parts of the system getting your generator into sync with the rest of the system. (UGLY things can happen). You may also be able to just simply close into the grid when you are around 49Hz and the system will self synchronize as the power level is coming up.

If you are operating in island mode and picking up a cold load. As the system is spinning up close into the load when you hit 50Hz. If you don't have a minimum load on the generator it will over frequency the load. Depending on what the load is and how good the voltage regulation is, that can range from minimal to catastrophic!

As far as I can tell, it doesn't answer the original question. Nor do you.

Yes, buddy. My answer about it was not, as you take it. Not the first time, I was not able to "fix" an "off label" note as a correct one IMHO. The note is to management about the formality of correcting votes. Have a nice evening.

Do we need a third voting option?

The inductive reactance increases with the frequency. That means that for fixed variables the acceptance of the circuit would be higher at 50 hertz than at 60 hertz. ??? If the supply voltage is one of those fixed variables then the circuit impedance would be higher for the 60 hertz frequency than the 50. ????

Yamdankee:

I like the ideas in your explanation of how the comment rating system might best be used. I also think many other members would be supportive of these ideas. If your comments can be taken as evidence then clearly Admin is also in favor.

.

With members and admin supportive of the ideas, why is this not what is happening?...what's the hold up? Who is resisting the change?

.

The answer is: the comment rating system.

.

If 'Off Topic' is not intended to mean 'the opposite of GA', then the system should not reduce the GA count when someone clicks 'Off Topic' (nor reduce the 'Off Topic' count when someone clicks 'Good Answer').

.

If doesn't matter that much what you label the choice, whether:

'off topic',

'cranial rectal impact symptom',

'further evidence of dunning-kreuger effect',

'I like ponies',

or, perhaps more straight-forwardly 'Bad Answer''

....the use will eventually be dictated by the effect, and if the effect is to offset any GA count, then is might as well be labeled 'Bad Answer'.

.

.

I think it would be far more interesting to let members rate a comment as a good/bad answer AND on/off topic.

.

It would also be valuable to show not just the net 'good' minus 'bad' or 'on' minus 'off' tally; even if the tally is near or at zero, knowing that a large number of members feel strongly enough to rate the comment and opinions are divided, is important.

.

.... I hope you find this comment to be good, even while it is obviously off topic.

look at your question first and research it. Fewer poles/ fewer RPM's = more available power. Or, you can take the KISS approach and not over engineer it.

If we take several stators of induction motor(same no of slots and size) and wind each to run at a different speed (2P,4P,6P,8P)which will give the maximum horsepower,the low speed motor or high speed motor?.

If a 50Hz induction motor(3000rpm) operates at 60Hz(3600rpm) will the increased mechanical forces cause any damage to bearing,shaft,rotor bars etc?.

It will surely do.

In saudi arabia in the eastern province(Hofuf town) in the 1980s frequency conversion was done from 50Hz to 60Hz in their power distribution system. I came to know that they replaced the governor springs of diesel engines driving storm water pumps to increase the speed. If they increase the speed won't there be any mechanical problems and can the same alternator give 60Hz?.

Thanks for all the positive feed back folks! I am re-posting both Part A and B as a direct answer. It was actually jut by accident that I saw the question but then had to respond. I am starting a new company and generally have not had time to read CR4 since Jan of 2012.

A)

The reason is lack of load. If you load the system or tie it into an existing 50Hz grid as it spins up it will sync to 50Hz. The system is designed to deliver X watts and must consume Y units of fuel to do so. The turbine control system will not begin to cut back on the fuel until it exceeds 50Hz.

Check the minimum load specification on the unit, until you exceed that minimum load the system will be above 50Hz.....

B)

I don't have time to read the manual for this device but...

one way is to manually intervene and hold the system to near the frequency of the grid you are attaching to before letting the controller take over. While near grid frequency, when the phase error is low connect the generator to the load. Then allow the automatic control system to take over. The generator will transfer power to the system by essentially pulling the grid forward in phase as the automatic control system takes over. If you are not supplying enough power to the generator it will actually draw power from the grid It is important to match phase when closing into an existing grid or you may trip other parts of the system getting your generator into sync with the rest of the system. (UGLY things can happen). You may also be able to just simply close into the grid when you are around 49Hz and the system will self synchronize as the power level is coming up.

If you are operating in island mode and picking up a cold load. As the system is spinning up close into the load when you hit 50Hz. If you don't have a minimum load on the generator it will over frequency the load. Depending on what the load is and how good the voltage regulation is, that can range from minimal to catastrophic!

The original question can be approached from the manufacturers point of view.

Most of the world runs on 50Hz, hence the designs are optimized for that. 60 Hz variant then is an off optimum design for yankees. To minimize having to design and keep too many different different parts in stock, leads to a 60Hz one being a derivative of the basic 50Hz one. Same turbine, same gearing (mostly or wholly), same mechanicals and magnetics in the generator. Different coils, different settings in the controllers.

The silicon steel used in the power industry has a significant hysteresis loop, hence losses turned into heating. At 60Hz vs. 50 it amounts to 20% higher heating from that source alone. To compensate, the heating from the coils need to be reduced by the same amount.

That explains it as a the general trend in the industry comfortably.

Mr. Won,

Since you posted the same basic question twice over a period of several months, I think you still don't understand the answer to your question. Are you comparing large-scale turbines such as the Siemens SGT5-8000H/SGT6-8000H and MHI M501G/M701G?

Phillipwon..

Based off this unit's Specs SGT5-8000H 375 Mwatt gas turbine

This is why your unit's output is higher at 50Hz

1Hz = 1/s So with this 60Hz=1/60s or 0.01666666666...s and 50Hz=1/50s or 0.02s this gives you 0.00333333...s over 60Hz =45830watts more power at 50Hz with all other things being equal.