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US 3,942,114 AGranted
Speed detector and indicator for DC motors
OwnerWilliam E. Keelinginventor
Life of this patent
Estimating the term…
Abstract
A speed detector for a direct current motor is coupled substantially in parallel with the motor such that only the motor input voltage and a function of the input current are inputs to the speed detector/indicator system. Analog speed detection is provided by using either operational amplifiers or single stage transistor circuits to sample the current and voltage to generate a voltage proportional to speed of the motor.
Claims7
In a motor control system having a motor for variable speed operation and a voltage throttle circuit for driving the motor, the improvement comprising:
- first and second amplifiers each having an input and an output, the output of said first amplifier being coupled to the input of said second amplifier, a first resistive means coupled between the output and the input of said second amplifier for providing adjustable feedback, an indicator circuit coupled to the output of said second amplifier for responding to any output signal therefrom, the inputs of said first and second amplifiers being coupled to said motor throttle circuit for receiving the input signals therefrom for providing an output signal indicative of motor speed, and a second resistive means coupled between the input of said second amplifier and said motor throttle circuit for providing an adjustable signal thereto.
Dependencies are inferred from the claim text.