Variable speed fan motor control for forced air heating/cooling system
AssigneeHoffman Controls Corp.
InventorsHoward P. Byrnes, Daniel B. Steffen
Life of this patent
Estimating the term…
Abstract
A forced air heating and/or cooling system utilizing an induction type fan motor is controlled by a controller circuit which is operable to continuously vary the speed of the fan motor during a start-up phase and a shut-down phase of the heating and/or cooling cycle. The controller circuit includes terminals for connection to the source of electrical energy for the heating and/or cooling system and for connection to the system controls without altering the control function or circuitry thereof. The controller circuit includes temperature sensors which are operable to control start-up and shutdown of the fan motor over continuously variable speed operating cycles in response to sensed temperature of the air being circulated by the fan.
Claims7
A method for controlling a fan motor of a forced air heating and cooling system for controlling the flow of air through said heating and cooling system, said heating and cooling, system including a first controller having a temperature sensor in an air conduit of said heating and cooling system for controlling operation of said motor during at least one of heating and cooling of a space, said method comprising the steps of:
- providing a second controller operable to be connected to a source of electrical energy and said motor, said second controller being operable for substantially continuously varying the speed of said motor between a minimum speed and a maximum speed independently of said first controller, said second controller including a first temperature sensor operable to sense the temperature of air in said conduit of said heating and cooling system, a second temperature sensor operable to sense a reference temperature of air in said space or returning from said space and circuit means operably connected to said temperature sensors for effecting a change in speed of said motor in response to a differential temperature sensed by said temperature sensors, respectively;
- operably connecting said second controller to said source of electric energy and said motor;
- and
- causing said second controller to substantially continuously change the speed of said motor between a minimum speed and a substantially maximum speed independently of said first controller and based on the differential temperature of air flowing through said heating and cooling system sensed by said temperature sensors, respectively.
Dependencies are inferred from the claim text.