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This is more representative of the fully developed DC throttles of today. It features full EMF feedback, Walkround Handheld control with inertia, braking, direction memory and overload protection. The first diagram shows the primary power input, the negative 12volt regulator and the circuit of the handheld control with a top speed power adjuster.
The voltage from the speed potentiomenter is buffered and supplied to the control voltage input of the 555 timer. The 'power' control adjusts the pulse width to suit the motor, 3 pole older motors need a greater width pulse to prevent cogging at low speed.
The threshold input to the 555 is a voltage dependent on the back EMF of the motor and controls, with the control voltage input, the pulse frequency and period. The 555 timer output pulse from pin 3 is used to trigger the driver MOSfet.
------ The description is continued on page.2
to Page.2
This is more representative of the fully developed DC throttles of today. It features full EMF feedback, Walkround Handheld control with inertia, braking, direction memory and overload protection. The first diagram shows the primary power input, the negative 12volt regulator and the circuit of the handheld control with a top speed power adjuster.
The voltage from the speed potentiomenter is buffered and supplied to the control voltage input of the 555 timer. The 'power' control adjusts the pulse width to suit the motor, 3 pole older motors need a greater width pulse to prevent cogging at low speed.
The threshold input to the 555 is a voltage dependent on the back EMF of the motor and controls, with the control voltage input, the pulse frequency and period. The 555 timer output pulse from pin 3 is used to trigger the driver MOSfet.
------ The description is continued on page.2
LINK TO IMAGE - cab555-A.gif
Circuit Schematic
