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US 4,734,012 AGranted
Blower speed control
AssigneeSSMC Inc.
InventorsAllan M. Dob, John W. Wurst
Life of this patent
Estimating the term…
Abstract
A speed controlling circuit for an alternating current powered blower motor is disclosed in which rectified direct current voltages are manipulated, regulated responsive to ambient temperature, and compared so as to provide reliable and cost effective blower speed control in proportion to ambient temperature and low blower speed cut off.
Claims5
A control circuit adapted to be coupled with an alternating current power source for varying the speed of operation of a blower drive motor in predetermined proportion to changes in temperature of a medium being impelled by said blower, said control circuit including:
- a triac arranged in series with the blower drive motor for regulating the time during each cycle of said alternating current power source that current is supplied to said blower motor,
- a voltage comparator having an output applied as a signal influencing firing of said triac,
- means generated by current alternation of said power source for applying voltage in a sawtooth shaped wave form to one input of said voltage comparator,
- means including a temperature responsive element arranged in a path of said medium being impelled by said blower for applying a voltage level proportional to the temperature of said medium to the other input of said voltage comparator,
- said voltage comparator serving to generate said signal on said output upon each instance of said sawtooth shape wave form voltage exceeding said voltage influenced by said temperature responsive element.
2 more elements
Dependencies are inferred from the claim text.