Time delay with control voltage sensing

摘要

A method is provided for controlling operation of an air conditioning unit. The method comprises supplying line voltage to activate a motor configured to operate the air conditioning unit, and monitoring a supply of control voltage in order to control operation of the air conditioning unit, the supply of control voltage being derived from line voltage. In response to detecting a control voltage below a predetermined threshold and/or by a predetermined percentage, a time delay is initiated. The method further comprises deactivating the motor if a predetermined increase in control voltage is not detected before the time delay expires.

主权项

1. A heating, ventilating, and air conditioning (HVAC) system, comprising:
a power source operable to supply an alternating current (AC) line voltage for operating a motor; a transformer electrically coupled to the power source and operable to convert the AC line voltage to an AC control voltage used to selectively energize at least one switching element, the switching element electrically connecting the motor to the AC line voltage when the switching element is energized; at least one sensor operable to monitor the AC control voltage supplied from the transformer; and a controller operatively connected to the sensor and operable to control the AC line voltage supplied to the motor via the switching element in accordance with the AC control voltage supplied from the transformer; wherein the controller is configured to initiate a time delay in response to the sensor detecting a reduction in the AC control voltage below a predetermined threshold and/or by a predetermined percentage; wherein the controller is configured to transmit a command to de-energize the switching element in order to discontinue operation of the motor at the expiration of the time delay in response to the sensor not detecting a predetermined increase in the AC control voltage before the time delay expires; and wherein, after expiration of the time delay and discontinuing operation of the motor, the controller is configured to initiate a randomly generated time delay and transmit a command to re-energize the switching element in order to restart operation of the motor at the expiration of the randomly generated time delay in response to the sensor detecting a predetermined minimum AC control voltage that exceeds a minimum startup voltage for a predetermined time duration.