Patent ID: 7672095

Claim:
A controller for establishing electrical connection between a motor and an alternating current power source having a first alternating-current voltage waveform and a second alternating-current voltage waveform, the controller comprising: a relay having a first relay contact and a second relay contact adapted to close to establish an electrical connection between a motor and a first alternating-current voltage waveform and second alternating-current voltage waveform, wherein a significant voltage potential exists between the first and second alternating-current voltage waveforms when either the first or second alternating-current voltage waveform crosses zero volts; a first electrical circuit having input connections adapted for connection to the first and second alternating-current voltage waveforms, the first electrical circuit being configured to provide a signal denoting a time when each of the first and second alternating-current voltage waveforms are each at a significant voltage value that is greater than 50 percent of the peak voltage of the waveforms, and the difference in voltage potential between the first alternating-current voltage waveform and the second alternating-current voltage waveform is at or near a minimum value, at which time the relay is initially switched to initiate closure of the first and second relay contacts; a second electrical circuit having input connections with the first and second relay contacts for monitoring the relay contact position, wherein when the relay first and second contacts are closed, the second electrical circuit is configured to provide a signal denoting a time when the relay contacts have closed and opened; a microprocessor configured to switch said relay causing the opening and closing of first and second relay contacts, wherein the microprocessor is configured to monitor the signal of the first circuit and the signal of the second circuit to determine a difference in time between when said relay is initially switched where the difference in voltage potential is at or near a minimum value, and when said first and second relay contacts actually close, where the microprocessor utilizes said time difference value in determining a switch initiation time relative to a time where the difference in voltage potential between the first alternating-current voltage waveform and the second alternating-current voltage waveform is at or near a minimum value, such that the first and second relay contacts close when the voltage potential between the first and second alternating-current voltage waveforms is at or near a minimum value, to thereby reduce the potential for arcing.