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US 4,378,199 AGranted
Variable speed drive
AssigneeCarrier Corporation
InventorBenjamin F. Hesler
Life of this patent
Estimating the term…
Abstract
The fan motor of a variable speed drive for a fan is positioned in response to thermostatic demand and a feedback signal responsive to the position of the variable speed drive. Changing thermostatic demand causes movement of the fan motor until an equilibrium position is reached again.
Claims4
A thermostatically responsive variable speed drive comprising:
- variable sheave fan motor means mounted on a movable base for driving a fan at a variable speed dependent upon the position of said movable base;
- means for reciprocably moving said movable base;
- normally open, differential pressure switch means for activating said means for reciprocably moving said movable base to respectively increase and decrease the driving speed of said fan motor means;
- means for supplying a first pressure signal to one side of said differential pressure switch means responsive to thermostatic demand;
- means for supplying a second pressure signal to an opposite side of said differential pressure switch means responsive to the position of said movable base;
- whereby when said first and second pressure signals are not in equilibrium said differential pressure switch means is closed to activate said means for reciprocably moving said movable base until said first and second pressure signals are again in equilibrium.
3 more elements
Dependencies are inferred from the claim text.