Combustion Engineering, Inc.

Harry L Wheeler

Floyd L Prestridge

Adolph August Schuetz

A transistorized power switching circuit for controlling the conductive state of a Darlington transistor. The circuit, driven by a single signal driver, operates to switch the Darlington transistor from a conducting state to a nonconducting state as well as from a nonconducting state to a conducting state. The circuit minimizes the number of components in the circuit that introduce time delays in switching the Darlington transistor. To further enhance switching the Darlington transistor from a conducting state to a nonconducting state, a reverse bias is employed to sweep the charge back out through the base of the Darlington transistor rather than permitting the charge to pass through the Darlington transistor then to the load. The reverse bias is maintained on the Darlington transistor for the duration of the off time regardless of the duration of the off period.

Darlington transistor driver with reverse base drive current

In a tumbling hammer type rapper (10), a feedback signal is provided via limit switch (30) and cam (28) mounted on rapper shaft (14) to control the rotation of rapper shaft (14) through one revolution. Rapper shaft (14) rotation is monitored to ensure that rapper shaft (14) completes one revolution, returning to the initial position, within a normal predetermined time period. If rapper shaft (14) fails to rotate from the initial position or fails to complete one revolution within the normal predetermined time period, an alarm is energized.

Growing community of inventors

Birmingham, AL, United States of America

Harry L Wheeler