Question

Linear lumped parameter models are not valid under situations as:

(a) Transmission pipe between the hydraulic pump and the motor causes a time lag in transportation of oil from pump to motor

(b) Transmission of heat by conduction or convection produces serious transportation lag

(c) Transmission pipe causes the time lag and loss of heat by conduction and convection

(d) Transmission of pipe causes neither any time lag nor any heat loss

I got this question during an interview.

Question is from Stability Analysis by Describing Functions in section Nonlinear Systems of Control Systems

Answer 1

Right option is (c) Transmission pipe causes the time lag and loss of heat by conduction and convection

The best explanation: Linear lumped parameter models are the models that simplifies the description of the behaviour of spatially distributed physical systems into a topology consisting of discrete systems and not valid when the pure time lags are negligible compared to other lags in the system.