In a motor control circuit for an electronically commutated reversible motor used in a ceiling fan, a control is used to reduce the voltage supplied to the motor for variable speed or torque operation. At the same time, a substantially smooth control voltage, dependent on the variable voltage supplied to the motor, is produced. This control voltage, which is used to enhance the adjustment rate, is applied to control a pulse width modulator, which produces output pulses which also control the flow of energy to the motor. When the control voltage reaches a value slightly past the desired minimum speed or torque setting, a signal is generated to change the direction of motor rotation. Means are provided to delay the actual reversal to protect the power switches in the control circuit. When power is first applied, the initial direction of motor rotation is set by a switch on the ceiling fan. The control circuit permits control of motor reversal from a wall location. The control circuitry is designed for use in a maximally integrated ECM control circuit. The invention also concerns a method of controlling an ECM, including reversal, and reversal combined with torque or speed control.
In order to prevent the performance of a motor from deteriorating due to a change in which the rotation rate of its rotor is to be increased suddenly, in a brushless motor in which a drive pulse whose pulse width is modulated in correspondence to a rotation rate setting signal input from the outside is formed and switching control is performed on the current supplied to the exciting coils by using output signals from the Hall elements that detect the position of the rotor and the drive pulse, the pulse width of the drive pulse is changed gradually and greatly until it reaches the pulse width that corresponds to the rotation rate setting signal when the upward change in the rotation rate of the rotor is to be large.
The present invention discloses an improved wiring construction of a control switch controlling a ceiling fan, the control switch being manually operated by a cord hanging from the control switch, the wiring construction comprising connecting means having two power source contacts and three connective contacts arranged systematically on a printed circuit board with its three connective contacts connected to a first end and a second end of a first winding of the drive motor driving the ceiling fan and to a tapping of the winding respectively; a condenser connected to one of the power source contacts, and to the first end of the first winding respectively through the connecting means; and a speed selecting switch actuated by the cord, and connected to the second end of the first winding, to the tapping, and to the other power source contact respectively through the connecting means for selecting different turns of the first winding to couple to the power source, so that the ceiling fan can rotate at different speeds.
A multispeed ceiling fan having a plurality of blades, a speed-selecting switch and an a.c. split-phase induction motor. The motor has a rotor and at least one stator winding. The speed selecting switch is arranged to apply respectively different voltages or currents to the motor for each respective selected speed. At least one lamp is connected in parallel to either the main stator winding or in parallel to a phase-shifting capacitor in series with an auxiliary stator winding, as an indicator providing a visible indication of the selected speed for the motor. The at least one lamp may comprise a plurality of lamps, at least all but one being in series with a respective plurality of Zener diodes so that they become energized in sequence as the voltage across the respective lamps or across the lamps in series with the respective pluralities of diodes increases.
A method for utilizing a three-wire programming box with a motor control circuit is provided. The method includes providing a three-wire to two-wire interface. The method further includes connecting the three-wire to two-wire interface between the three-wire programming box and the motor control circuit such that the three-wire programming box communicates bi-directionally with the motor control circuit utilizing less than three connections between the three-wire to two-wire interface and the motor control circuit.
An off state demonstrating device on a line-pulling switch for a ceiling fan, is characterized in that a display or demonstrating device is jumper connected at the off position of the switch, so that when the switch is in an off state, the display or demonstrating device can be turned on and a user can be advised that the ceiling fan is in an off state.
