Factor in Electrical calculation

Electrical Basic Concepts,

Factor in Electrical calculation 

Electrical factor given below are the important  factor while designing and understand the demand of a load some of them are given below

a)  Load factor : 

          The ratio of the load that a piece of equipment actually draws when it is in operation to the load it could draw (which we call full load).

            For example, 

    An oversize motor - 20 hp - drives a constant 15 hp load whenever it is on. The motor load factor is then 15/20 =     75%.

 

b)  Use (or utilization) factor 

          The ratio of the time that a piece of equipment is in use to the total time that it could be in use.

    For example, 

 The motor above may only be used for eight hours a day, 50 weeks a year. The hours of operation   would then be 2000 hours, and the motor use factor for a base of 8760  hours   per year would be 2000/8760 = 22.83%. With a base of 2000 hours per year, the  motor  use factor would be 100%. The bottom line is that the use factor is applied to get    the   correct number of hours that the motor is in use.

 

 c)    Diversity factor :

       The probability that a particular piece of equipment will come on at the time of the facility's  peak load.

The diversity factor is the most complicated of these factors. For example, we might have  ten air conditioning units that are 20 tons each at a facility. In Florida we typically assume  that the average full load equivalent operating hours for the units are 2000 hours per year.  However, since the units are each thermostatically controlled, we do not know exactly when each unit turns on. If the ten units are substantially bigger than the facility's actual  peak   A/C load, then fewer than all ten units will likely come on at once. Thus, even  though each unit runs a total of 2000 hours a year, they do not all come on at the same. The diversity factor does not affect the kWh; it only affects the kW.