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from the control department...
accelaration fsr
Application Questions and Problems topic
Posted by any one on 16 December, 2007 - 5:21 pm
How can I reduce the acceleration time and increase the rate of FSR in turbine ms9001e? What is the best value of acceleration time and FSR for normal operations? my turbine control speedtronic MKV


Posted by CTTech on 17 December, 2007 - 5:41 pm
Acceleration time is based on the cranking motors' ability and the warm up timer up to 60% speed.

After 60% speed; it is a easy ramp to 95% speed.

Contact GE! If you wish, they will tune your turbine to start, fire, accelerate, and sync in 7 minutes.


Posted by CSA on 19 December, 2007 - 1:10 am
Yeah, and then they'll gladly take your money for spare parts due to increased maintenance factor.


Posted by abca on 27 December, 2007 - 10:41 am
can you tell me if the acceleration is too long
this not effect on the exhaust turbine temp.?
I mean if the time of the acceleration is too long and fsr increase .this case not effect on turbine outlet temp?

can write to me the mathmatical relationship between the acceleration and FSR and turb.out let temp.

aboforat_2005@yahoo.com


Posted by CSA on 28 December, 2007 - 12:40 pm
People need to be very careful with their posts and provide all the details of their posting. Accelerating a turbine in 6.5 or 7 minutes is *not* recommended except under emergency conditions and even then not all units are capable of this.

Turbine manufacturers and packagers who can tell owners if their unit is capable of faster acceleration will also usually provide a "maintenance factor" which is used to calculate the effect of these fast starts and fast loads, and these maintenance factors usually greatly decrease the intervals between maintenance outages; in other words, each fast start can be worth as much as 20 normal starts.

It's even possible that CTTech was being slightly sarcastic, meaning that the unit was inadvertently set to accelerate to synch speed in 7 minutes. But, he didn't provide the details so we can't know.

When you say if anyone can tell you if acceleration is taking too long, you need to tell us what kind of turbine you have and what kind of acceleration times you are experiencing. And, how you define acceleration: From establishment of flame? Or from zero speed? Or
after warm-up? Or, after synchronization (more commonly referred to as "loading rate" since if the unit is a generator drive it usually doesn't accelerate when the generator breaker is closed)? Some people are interested in reducing the purge time, the time during which the unit is accelerating up to firing speed?

What exactly is the period or condition you have concerns about? There was information provided in the early part of this post about *typical* acceleration rates. Was that not helpful or applicable to your condition?

What is the maximum exhaust temperature you are experiencing during starting and acceleration?

So, in addition to responses with adequate details, we need requests for information with adequate details. How about telling us what fuel(s) you are starting on? The exhaust temperature spreads you might be experiencing during starting and acceleration to synch speed? What kind of starting means (electric motor; diesel motor; expander turbine) and what kind of torque converter (fixed or adjustable) is used on your unit(s)?


Posted by abca on 29 December, 2007 - 12:34 pm
dear sir
our starting motor is electric motor and the turque converter is adjustable. just i ask for information if the angle for the torque converter varied (increase or decrease) this effect on the accelartion. then the time for the accelartion will vary also. then what is its effect on the temperature turbine outlet?
because slow accelartion and more fuel or vise versa. can you give ne a function for this


Posted by CSA on 30 December, 2007 - 3:38 pm
Since you don't seem to be willing to provide the requested information without playing "20 Questions", if you have a Speedtronic turbine control panel (which we don't know, because you haven't told us) the acceleration rate can be found in the sequencing (Speedtronic elementary for a Mark II or a Mark IV; CSP for a Mark V; Toolbox for a Mark VI).

The acceleration is a function of the generation and vintage of the Speedtronic control system. If the unit has a Speedtronic turbine control system, it likely has a Control Specification - Sys Settings "drawing", also, which can have some information in Sect. 2 or 3 about starting.


Posted by CTTech on 30 December, 2007 - 3:39 pm
I cannot give a function because it is usually based on the performance of the cranking motor itself.

CSA is correct. I was being sarcastic. The torque convertor (probably vought) and the cranking motor are used to accelerate the turbine to 60% (self-sustaining) speed.

Exhaust temp should not be a factor during this part of the start sequence. If it is, other problems exist. FSR is generally clamped to a minimum value during this portion of the sequence. Temperature control can override this and drive the FSR signal to zero and trip the turbine.

If the torque convertor vane angle is modified, one will probably overamp the cranking motor. The cranking motors on some turbines are undersized and cannot withstand repeated high amp starts.

Please observe cranking motor amps from the ignition permissive until the convertor has reached maximum vane angle (generally prior to 20% speed after flame has been established).

Alway consult GE documentation regarding recommended purge times, cranking motor performance, exhaust temp warmup parameters, and generator loading characteristics.

A fast start will usually count as 10 normal starts in regards to maintenance intervals.


Posted by abca on 3 January, 2008 - 4:19 pm
Our turbine type is Frame 9E Mark VI Speedtronic with toolbox. We can use gas and liquid fuel for starting.

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