Emerson Electric Company

Craig J Nordby

James L Skinner

J Stephen Thorn

Marco Venturini

Pradeep K Sood

Ciaran O'Breartuin

A blower motor unit having a variable speed motor and that is suitable for direct, drop-in replacement in a residential HVAC (heating, ventilation, and air conditioning) system that employs a PSC motor. The blower motor unit is provided with a neutral input and two hot AC line connections, one for connection to the heating power source and the other to the cooling power source. The blower motor unit senses which of the inputs is energized by sensing either voltage or current on at least one of the inputs, selects one of at least two reference signals in accordance with which input is energized, and presents the control input of the replacement variable speed motor with the selected reference signal, thereby controlling the speed of the variable speed motor. This motor control unit, and the method by which it selects one of two signals for application to a control input of a motor, are also independently useful to control any type of motor having at least two modes of operation.

Direct replacement variable speed blower motor

Air handling apparatus (10) delivers a volume of air at a generally constant flow rate regardless of changes in the operating conditions of a system with which the apparatus is used. A blower (12) pushes air from one point to another. The blower is operated by a blower motor (14). A switch (16) controls application of power to the motor. Sensors (20) are used to sense the current drawn by the motor and the motor's operating speed. A flow controller (22) establishes a desired air flow rate to be provided by the blower. A processor (18) is responsive to the sensed current (I), motor speed (S), an input (C) from the flow controller, and constants (K1-K4) related to performance characteristics of the blower to determine a torque required by the motor to produce a predetermined air flow rate. The torque value is determined as a function of the combined motor speed input from the sensor and an input from the flow controller. The processor is responsive to the calculated torque value for the motor to supply a control signal to the switch to control application of a voltage to the motor. This voltage is sufficient for the motor to produce the calculated torque. The processor includes signal logic (28) by which the control signal can be modified first in response to the sensed current drawn by the motor.

Constant air flow control apparatus and method

A drive system for a household appliance incorporates an electric motor. A control panel allows the user of the appliance to select from among various performance options which the appliance is able to perform. A microprocessor, functioning as a first control unit, is responsive to the selections and to various appliance sensors monitoring operational status of the appliance to control the operation of various components within the appliance by which the selected options are performed. An AC-DC converter and inverter supply electrical power to the motor. A second control unit, operating at a relatively faster rate of speed than the microprocessor, controls the supplying of power to the electric motor to achieve proper operation thereof.

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Chesterfield, MO, United States of America

Craig J Nordby