COMPARING TRANSDUCER TYPE ON A ROLLER GIN STAND FEED CONTROL

Abstract

Three types of electrical transducers (power, power factor, and current) were tested for use on a roller ginstand automatic feed control system. The automatic control system monitored and adjusted the seed cotton feed rate to produce a pre-selected load level on the gin stand rotary knife while automatically compensating for differences in the seed cotton such as trash and moisture content. An electrical transducer, which is part of the design of the automatic control system, measured the input signal from a motor driving the rotary knife, and then proportionately converted and sent this signal as direct current to a digital controller. The controller then output the dc signal to a motor control that operated the feed rollers on the feeder. Transducer types tested included a power transducer which measured the input signal in kilowatts, a power factor transducer which measured the power factor between the voltage and current waves, and a current transducer which measured the signal in ac amperes. Results showed that all three transducers convertedthe input signal from the rotary-knife motor to an output dc signal. However, because the rotary-knife motor operated mostly at a low load, the power and power factor transducers converted the signal more effectively.