Designing and Simulation of Single Phase Induction Motor with a Smooth Start

Due to supply of abrupt voltage at start the motor may gets damaged and many times the winding gets burnt. An induction motor during the initial starting condition draws up much higher current than its capacity and the motor instantly reaches the full speed. This results in a mechanical jerk and high electrical stress on the winding of the motor In this project we intend to present a single phase induction motor with a smooth start. By using SCRs and other components such as op-amp, the speed of motor picks up gradually up to maximum. The motor and the two anti-parallel SCR are connected in series. The SCR receive a delayed firing angle due to delayed pulses received from the operational amplifier. The operational amplifier develops a saw-tooth voltage by comparing the zero voltage pulse. The saw-tooth voltage is further compared with the varying voltage produced by the charging and discharging of the capacitor. Henceforth, producing a delayed pulse and feeding it to the SCR as delayed pulse for firing angle.