Circuit for Monitoring Parallel DC Blower Motor Operation
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
This article describes a circuit arrangement by which two blower motors can be monitored for proper shaft rotation. A hall effect device built into each motor issues pulses proportional to shaft revolutions. These pulses are integrated to yield a voltage inversely related to shaft speed. A low voltage means the motor shaft is turning adequately. Conversely, a high voltage signals an error. The addition of a logical OR gate to the circuit allows multiple blowers to be monitored simultaneously. The circuit arrangement disclosed herein offers high sensitivity and reliability for monitoring blower motor performance (rpm) when one or more DC blower motors are installed in a housing.