Pump controller

A pump control apparatus comprising:

• a voltage filter capable of being coupled to an AC power source and of generating a first two-state output signal;
• a current filter capable of being coupled to an AC power source and of generating a second two-state output signal;
• a power supply circuit capable of producing a DC power signal;
• a controller coupled to the voltage filter, the current filter, and the power supply circuit and operable to produce a control signal based on the time differential between the first and second two-state output signals;
• and
• a switch coupled to the controller and operable to open in response to the control signal.

A pump comprising:

• a housing;
• a motor positioned within the housing;
• a control module positioned within the housing, the control module including
• a voltage filter capable of being coupled to an AC power source and of generating a first two-state output signal;
• a current filter capable of being coupled to an AC power source and of generating a second two-state output signal;
• a power supply circuit capable of producing a DC power signal;
• a programmable device coupled to the voltage filter, the current filter, and the power supply circuit and programmed to produce a control signal based on the time differential between the first and second two-state output signals;
• and
• a switch coupled to the programmable device, operable to open in response to the control signal, and having a semiconductor device coupled in parallel to a second switching device.

A method of controlling an electric motor pump coupled to a switch, the method comprising:

• providing an AC power signal having a positive half cycle and a negative half cycle;
• measuring the voltage of the AC power signal and generating a first two-state output signal that is in a logic high state when the measured voltage is on the positive half cycle and is in a logic low state when the measured voltage is on the negative half cycle;
• measuring the current of the AC power signal and generating a second two-state output signal that is in a logic high state when the measured current is on the positive half cycle and is in a logic low state when the measured current is on the negative half cycle;
• determining a phase difference based on a time difference between the first two-state output signal and the second two-state output signal;
• comparing the phase difference to a predetermined threshold value;
• opening the switch if the determined phase difference is equal to or greater than the predetermined threshold value;
• closing the switch after a predetermined amount of time has elapsed;
• and
• repeating the acts of measuring the voltage, measuring the current, determining a time difference, comparing the determined phase difference, and opening a switch.

A pump control apparatus comprising:

• a voltage filter having a zero-cross detection circuit and capable of being coupled to an AC power source and of generating a first two-state output signal;
• a current filter having a zero-cross detection circuit and capable of being coupled to an AC power source and of generating a second two-state output signal;
• a power supply circuit capable of producing a DC power signal;
• a controller coupled to the voltage filter, the current filter, and the power supply circuit and operable to produce a control signal based on the time differential between the first and second two-state output signals;
• and
• a switch having an semiconductor device and a relay coupled in parallel circuit branches, the switch coupled to the controller and operable to open in response to the control signal.

A pump comprising:

• a housing;
• a motor positioned within the housing;
• a control module positioned within the housing, the control module including
• a voltage filter capable of being coupled to an AC power source and of generating a first two-state output signal;
• a current filter capable of being coupled to an AC power source and of generating a second two-state output signal;
• a power supply circuit capable of producing a DC power signal;
• a programmable device coupled to the voltage filter, the current filter, and the power supply circuit and programmed to produce a control signal based on the time differential between the first and second two-state output signals;
• and
• a switch having a low heat generating device and a high heat generating device coupled in parallel circuit branches, the switch coupled to the programmable device, and operable to open in response to the control signal.