CPC F04D 19/005 (2013.01) [F04D 27/008 (2013.01); F05D 2270/335 (2013.01)] | 17 Claims |
1. A motor controller configured to be coupled to a motor that is coupled to a backward-curved fan, said motor controller comprising a processor coupled to a memory, said motor controller is configured to:
operate the motor to rotate the backward-curved fan at a first speed in a forward direction that causes a fluid to move from an inlet of a fluid flow path to an outlet of the fluid flow path, wherein the backward-curved fan is curved backward with respect to a direction of movement of the fluid through the fluid flow path, and wherein restriction of the fluid flow path does not increase a torque associated with the motor while operating in the forward direction;
store a schedule for a restriction detection mode in said memory, the schedule defining times when the motor is to be operated in the restriction detection mode;
operate, in accordance with the schedule, the motor to rotate the backward-curved fan in a reverse direction that is opposite the forward direction, wherein restriction of the fluid flow path increases the torque associated with the motor while operating in the reverse direction;
determine the torque associated with the motor while the motor is rotating the backward-curved fan only in the reverse direction during the restriction detection mode;
determine that the torque is not within a predefined threshold range stored in said memory, the predefined threshold range indicating an expected range of torque for resulting from the backward-curved fan to operate operating in the reverse direction when no restriction is present in the fluid flow path; and determine that a restriction exists in the fluid flow path in response to determining that the torque is not within the predefined threshold range.
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