Electrical equipment can fail spontaneously and therefore you need to assess the risk when transiting electrical rooms. Please have a look at the following incident that occurred on the Queen Mary 2 cruise ship recently...
What are the benefits or disadvantages between Inwardly turning and outwardly turning props on twin shaftline ships?
What direction do props turn on four shafted ships?
Thanks
Thanks everyone who took the trouble to answer so fully.
The reason I ask was this topic is not clearly covered in many electro or mechanical text books.
Hopefully a very simple question!
How do you calculate shaft torque from air-gap torque under transient conditions?
If my load inertia is J1 and my motor inertia is J2, is it as simple as Shaft Torque = J1/(J1+J2)*air-gap torque?
Thanks
Possible source of even harmonics is transformer in-rush. Perhaps when the driver starts the winder he closes the convertor transformers whose in-rush current interacts with the filter bank and is the source of 4th. I am unclear how a 6 or 12 pulse convertor generates 4th harmonic, unless one...
Thank you both rbulsara and Jbartos.
Makes sense, I am aware that the amortisseur winding has a significant effect. In fact some synchronous motors have no amortisseur winding and this means the X"" is very high so the fault torque is very low.
I am curious to know the following, if I had two synchronous generators, both rated equally for kVA and voltage, if they had different sub-transient reactance, say one at 10%, the other at 20%, how would they physically differ in internal configuration/construction or size? Secondly, how does a...
We are commissioning a 25MVA, 4160V brushless 2-pole alternator driven by a gas turbine at 60Hz (3600rpm). Today at with the gas turbine at synchronous speed and alternator off the bars the excitation was powered up for the first time. The AVR/excitor commissioning team set the manual...
Hello Forum,
I am interested to understand what effect the variation in electrical parameters of a generator has on its construction, size and relative cost.
For example, if I have to select a generator with a high sub-transient reactance, how different in size is this machine compared to one...
500MW is a big complex, even for a complete steel production plant. Is it a USX site?
Mind you a large Hot strip mills may have 120MW of connected plant.
Compensation is available and is usually applied at various levels close to the offending plant, because the distribution system is complex...
I totally agree with 'busbar'.
In europe hinges would be classed as a "fortuitous" earth. To ensure touch potentials are low whilst fault currents flow, a positive mechanism for earthing must be applied using a strap. Hinges are not designed to carry current, so cannot be...
Proving the "theory" of this failure mode will not be easy. EMC issues are never black and white.
The articles suggested by Busbar are excellent papers - what is interesting is that this type of problem has been known about for 40 years or more, but manufacturers and system...
Problems like this are not necessarily with the relay unit. There are lots of cables coming into relays that can carry common mode and differential mode pick-up. Inadequate installation earthing is generally the most likely suspect. GE are a big organisation that do extensive EMC testing of...
IEC is +/-15%. It is usually practice to take the -15% which gives the worst case reactance after factory test and gives the maximum possible current.
I cannot imagine ANSI is much different.
