Recent content by subtech

At what speed does the rotor operate under normal conditions?

This should help you. It gets right at the heart of your question in a relay technician/relay engineer sort of way. http://www.gedigitalenergy.com/multilin/notes/artsci/index.htm I would download the entire book, but in particular you will want chapters 3 & 4. Post again if you need further help.

You may find this interesting http://www.copper.org/applications/electrical/busbar/

This is best shown with a diagram, but I try to do this with a simple description. Picture the stator windings around the inner circumference of the machine housing, each phase winding has a "reference" mark midway along its distribution. The rotating magnetic field emanating from the rotor...

Interesting... http://en.wikipedia.org/wiki/Lightning

Look here: http://en.wikipedia.org/wiki/Twisted_pair hope this helps

I did not watch the entire video, but what I saw in the first 2-3 minutes was nothing unusual. The "discs" are insulators as was previously stated by others. The brown colored insulators most likely were manufactured many years ago. (30-50 yrs) They are made from porcelain. The brown color...

The wattmeter responds to current that is in phase with the voltage. In your picture, The reference voltage is Y-B. (picture this vector as horizontal, the base of the delta triangle). The current is from phase R. Its vector would be vertical or at 90 deg to the voltage vector. If the power...

Your concern about the number of starts per hour for large motors is correct. Overheating of the rotor windings & rotor structure is the primary concern in that case. To say that starting the motor several times in a few hours caused the switchgear to catch fire is a stretch however. A...

Speaking very generally, when considering single phase motors one should visualise a pulsing magnetic field eminating from the stator windings and not a rotating one. During the positive portion of the cycle, the uppermost stator pole could be likened to the North pole of a magnet. (of course...

As previously stated, EMF stands for electromotive force. It is what makes the electrons move from atom to atom. How much electromotive force is present between two points in a circuit is measured in units of Volts. Voltage is a "Unit of Measure" . If you were to apply enough electromotive...

The reverse power relay(32R) s a standard protection feature for most all synchronous generators. It measures and monitors direction of power flow at the generator terminals. Power (watts) from the gen to the system is normal. Power flow from the system into the gen is abnormal and very much...

The arcing you see is ionization of the air beween the chopper and the line thus creating a conductive path. A small amount of current does flow through the arc path to helicopter thus bringing it to the same potential as the line. This current is often referred to as "charging current". It...

I'm sure there is a reasonable and durable solution to your co-axial cable problem. These people wrote the book on cable and waveguide. Look here: http://www.commscope.com/andrew/eng/index.html

It should be remembered that three phase fault current is limited only by the the reactance of the source and perhaps additionally the R and X of any conductors between the source and the fault point. The closer the fault to the source, the higher one should expect the fault current magnitudes...