Parvovirus B19. Parvovirus B19 infections in children present as a viral exanthema, and in adults as a cause of arthralgia and arthritis. The incubation period is 7â10 days with non-specific flu-like symptoms in the first week followed by arthralgias or arthritis in up to 60% of patients in the second week.
Variable Torque Motors - American Made Efficiency. One of the largest down-sides to electric motors is their inherent efficiency range and, in hybrid systems, the drag they can create on the drive train.
For the DC motor the commutator is used to alternate the magnetic field created by the DC current, although, for AC motor the magnetic field is already alternated by the nature of the AC current. an alternative magnetic field leads to a non zero average torque.