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.
Variable Frequency Drive (VFD) A Variable Frequency Drive (VFD) or adjustable speed drive is a motor controller device that runs an electric motor by varying the voltage and frequency supplied to the electric motor. VFDâs are also known as AC drives or microdrives since they control the speed of a motor, generally a three phase motor.