Circuit and method for controlling electric power delivered to an electric motor

A method implemented in a controller for controlling electric power delivered to an electric motor, comprising:

• receiving, at the controller, one of a first command and a second command;
• sensing, at the controller, the electric power delivered to the electric motor;
• when the second command is received at the controller, resetting a first latch at the controller and transmitting a second control signal from the controller to a reversible contactor electrically connected to the electric motor and to a power source, the second control signal causing the reversible contactor to deliver current from the power source to the electric motor to cause the electric motor to operate in a second direction;
• when the first command is received at the controller while the first latch is not set, transmitting a first control signal from the controller to the reversible contactor, the first control signal causing the reversible contactor to deliver current from the power source to the electric motor to cause the electric motor to operate in a first direction;
• setting, at the controller, the first latch and terminating transmission of the first control signal when the level of the electric power delivered to the electric motor exceeds the power threshold while the first command is being received at the controller;
• terminating, at the controller, transmission of the first and second control signals when none of the first and second command is received;
• resetting a second latch when the controller receives the first control signal;
• and
• setting, at the controller, the second latch and terminating transmission of the second control signal when the level of the electric power delivered to the electric motor exceeds the power threshold while the second command is being received at the controller.

A method of controlling a winch operatively connected to an electric motor, comprising:

• receiving, at a controller from a user-operable switch, one of a first command and a second command;
• sensing, at the controller, a level of electric power delivered to the electric motor;
• when the second command is received at the controller, resetting a first latch at the controller and transmitting a second control signal from the controller to a reversible contactor electrically connected to the electric motor and to a power source, the second control signal causing the reversible contactor to deliver current from the power source to the electric motor to cause the electric motor and the winch to operate in a reverse direction;
• when the first command is received at the controller while the first latch is not set, transmitting a first control signal from the controller to the reversible contactor, the first control signal causing the reversible contactor to deliver current from the power source to the electric motor to cause the electric motor and the winch to operate in a forward direction;
• setting, at the controller, the first latch and terminating transmission of the first control signal when the level of the electric power delivered to the electric motor exceeds the power threshold while the first command is being received at the controller;
• terminating, at the controller, transmission of the first and second control signals when none of the first and second command is received;
• resetting a second latch when the controller receives the first control signal;
• setting, at the controller, the second latch and terminating transmission of the second control signal when the level of the electric power delivered to the electric motor exceeds the power threshold while the second command is being received at the controller.