Strep throat (an infection of the throat caused by group A streptococcus bacteria, also called Streptococcus pyogenes) is most contagious starting a few days before symptoms show up and decreases after a person has been on antibiotics for at least 24 hours.aused by group A strep infection, the illness causes fever, sore throat, white spots on the tonsils, swollen lymph nodes, a bright-red strawberry tongue, and a tell-tale red rash that starts on the abdomen and spreads throughout the body within two days.
An induction or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.ince rotation at synchronous speed would result in no induced rotor current, an induction motor always operates slower than synchronous speed. The difference, or slip, between actual and synchronous speed varies from about 0.5 to 5.0% for standard Design B torque curve induction motors.
DC and AC motors have differing means of speed control. While DC motors are controlled by varying the armature winding's current, AC motors simply vary the frequency. An induction motor and a synchronous motor are two types of AC motors. An induction motor uses a magnetic field on a rotor that is created by an induced current. A synchronous motor is powered by a current through slip rings or a permanent magnet. Synchronous motors usually run much faster than induction motors because of the presence of slip rings. DC electric motor repair is much more expensive than AC electric motor repair. Paper producing machines and steel mill rolling machines are a few examples of a DC electric motor.