Frankly speaking, your experience will be quite useful in Oil & Gas, provided you choose to work in a firm which executes bigger projects ($2 billion and up). Such plants require extensive system studies, higher voltages and stuff that you would be conversant with. Relay coordination, Arc Flash...
Very basic calculations with fault currents available at bus, with subsequent impedance of the length of cable, reveals that fault currents fall to negligible values at the end of the cable. Here the premise is that if the cable routing has followed the proper codes/specs, it will be a well...
eengK..do you have taps from this o/h line for various loads? Then the voltage drop calculations get a bit tricky..the last section near the source carries current i1+i2+i3+..+in. For the next section the line carries i2+i3+..+in..if the first tap withdraws i1 current. I had a spreadsheet which...
In low voltage, short circuit is seldom the factor for selection of cable sizes. It is always the ampacity & voltage drop which rules the roost. Usually the impedance of the cable is good enough to drop the short circuit values to very low values within a few mts from the MCC / LV bus. Also, the...
One factor to remember is that if it is a motor load, a running motor will convert the running kinetic energy to electrical energy and feed power back to the fault. A thumbrule for motor contribution to a line fault is 4 times the FLA of the motor. Thus besides the initial temp of the cable...
Some battery vendors have Battery monitoring system which monitor the Battery Internal resistances and give online values, which can be easily accessed. I had seen the results in one of the Battery vendor's presentations and I liked the graphics. As far as Battery warranty goes, it is one of...
The tolerance on DC bus voltage is usually 90V to 140V. Now , as correctly specified by DLynn, 2.25V/cell is the correct float voltage. Now 125VDC is the 'nominal voltage' whereas 135VDC is the actual float voltage. You should be more worried of the end cell voltage which typically is 1.75V/cell...
FSCK..I did some study on Xmer inrush which depends much more on factors like remnant flux from earlier energization, core dimensions etc. It is an inherent nature of that particular Xmer and can be worse when the switching takes place at Voltage zero. X/R ratio is not that important (unlike in...
I wanted to know if anybody has carried out calculations for a. Floating voltage b. Circulating current & c.Shield loss per unit length...for 25kV, 3C, cable with core shields ungrounded at one end / grounded at both ends. Interestingly, some relevant sections in IEEE 525-2007 have been removed...
Hi Xnuke..I agree with you..but there are some restrictions in the ways that we employ methods is a normal EPC project..Our motor data sheets are all in Excel. Each one has a seperate document number which is closely linked with the motor Tag no. If anybody can help in getting Vlookup working...
Well JLSegull..by definition, "adequate ventilation" is that which is sufficient to prevent accumulation of significant qts .....Now to prove this, we will have to carry out fugitive emmission calcs...if the volume of the enclosed space is large enough, and fugitive emission rate is small...
I was thinking of simple Vlookup, with the path of the file for search purpose..but I was not succesful...the layout is consistent, but unortunately because of insertion of rows, the cell nos may not be identical for the same piece of info..say speed/HPrating/No of poles etc....
I must say thanks to all of you..the Macro works..and it should be a very useful tool, if Data sheets with say 95% generic data and remaining custized data is required to be generated.
I have a Data sheet for each LV motor, with various data viz. HP, No of poles, FLA etc.
Now, I want to populate a single worksheet with this data against the motor Tag. Is it possible to pick up the data from multiple Data sheets, located in the same folder?
Hi SLCEIT...One of my colleagues has started his Civil design website :www.civildesignhelp.info/
Possibly you will get some reference here for your area of interest. Cheers
API has recommended dilution ventilatin is various sections, viz.6.6.2.4.5, 6.6.2.4.8,7.3 etc...also in the APpendix, the IEC method of Hypothetical volume has been explained.
I believe this topic has been discussed in the forum previously..Can we reclassify an enclosed area with Ventilation? If we do not want to conduct fugitive emission studies, and we have three air changes (with detectors), is this good enough for a Zone 2 Classification as per API 505?
