DESIGN AND FABRICATION OF ELECTROMAGNETIC DYNAMOMETER FOR MICRO-POWER MEASUREMENT

The torque measurement has been a challenge especially for low torques. The amplification of the torque with either pulleys or gears is one way out, but it introduces its own losses and affects the accuracy of the measurand. The magnetic force applied to the flywheel is one of the nascent option which is explored in this present work. The prime mover is low power impulse steam turbine, but a 50 W generic universal electrical motor is opted for prime mover. The speed being very high, it is reduced at 4 times with corresponding amplification in torque. A properly bearing supported shaft with flywheel is coupled to this motor through V-belt pulleys. The electromagnets are applied at the circumference with predefined gap. The arrangement to vary this gap is provided on the setup. The three DC voltages are applied to electromagnets for so as to produce three different magnitudes. This calibrated force in turn torque applied to steam turbine, where the torque generated is still lower. Hence, thus calibrated force i.e. torque shall enable to estimate the power developed, which is essentially useful for efficiency calculations. The results obtained through this present work are encouraging