How does the Load Sentinel work?
A. The Load Sentinel monitors the shaft loading on an AC motor by monitoring the power factor rather than merely sensing the motor current. This is important because the current draw on a motor will change as the windings heat up and change resistance. However, the power factor is directly related to the load and is independent of temperature. The power factor is a measure of the phase relationship between the voltage and the current. The current zero crossover (which is the reference point) is achieved by passing one of the motor leads through the transducer on the Load Sentinel. Once the voltage and current references are available, the unit is ready to function. However, it must still be adjusted to indicate what power factor value is considered normal; and what deviations from that norm are cause for alarm. This is achieved by simply adjusting four single-turn potentiometers.
