how to find values of R and L (in ohm and henry respectively) of RL load whose parameters are specified in Watt?
The voltage rating and power factor (PF) should also be known. If the PF is not none, you can get it by applying the rated voltage and measuring all of current and P and Q, or you can measure the power factor also. If the load is a motor, you need to do the two well-known tests that are called the open circuit and short circuit tests.
If not motor, then, from the measurements above, you can obtain R and L.
If there is difficulty to build the test circuit in the lab, you can simulate it in a suitable simulation software. MATLAB/SIMULINK would be useful.
Hope this helps.
Without additional information (like e.g. corresponding apparent power, power factor) you can only determine the R-Part of the load!
Which appliance do you have in mind? Do you have additional information maybe?
Active power(P)=W=VICos(phi)=VI=I(sqr)R, as p.f angle is zero for resistive load. Hence if W and I=W/V is known R could be obtained easily.
Reactive power(Q)=VISin(phi), L or LC with higher L effect p.f would be lagging(.8 lag normally for power system).
C or LC with higher C effect p.f would be leading, Total power(VA)=P +/- j(Q).
V=I.Z, Z=V/I, Z=R +/- jX, hence by knowing Z and R, X of system could be obtained, and X=2(pai)fL, for lagging p.f, L could be obtained. X=1/2(pai)f.C, hence C could be obtained for circuit with leading p.f.
- Badges
- Science topic
- Similar topics
- Engineering
- Control Theory
- Control Systems
- Control Systems Engineering