The deflecting torque of induction type instrument is Td=ϕ1ϕ2‌sin‌β‌cos‌α The torque in induction type instrument is directly proportional to 'cos α'. Therefore in order to maximize the torque, the angle should be near to zero. The torque in induction type instrument is directly proportional to 'sin β'. Therefore the angle 'β' should be near to 90° in order to maximize the torque. The angle 'β' is the angle between two shunt coil flux and series coil flux and quadrature means 90°.