Motor starter and diagnosis method

A diagnostic method for a motor starter configured as a direct starter and connected to a three-phase electric motor, the method comprising:

• providing the motor starter in an inactive state;
• closing of a first phase with a first electromechanical switch;
• opening of the first phase and closing of a third electromechanical switch in a third phase;
• closing of a first semiconductor switch in the first phase and a second semiconductor switch in a second phase by active control of the first and second semiconductor switches;
• closing of a first electromechanical switch in the first phase and a second electromechanical switch in the second phase, wherein each of the first electromechanical switch and the second electromechanical switch form a bypass circuit with the first and second semiconductor switches;
• rejecting active control of the first and second semiconductor switches;
• wherein a fault in the motor starter detected when during closing of the first semiconductor switch in the first phase and closing of the second semiconductor switch in a second phase or opening of the first phase and closing of the third electromechanical switch in the third phase a current flow is detected by at least one measuring apparatus in the first phase, the second phase, or the first phase and second phase or when during closing of the first semiconductor switch in the first phase and closing of the second semiconductor switch in the second phase a current flow of zero is detected by-the at least one measuring apparatus in the first phase, the second phase, or the first phase and the second phase.

A diagnostic method for a motor starter configured as a reversing starter and connected to a three-phase electric motor, the method comprising:

• providing the motor starter in an inactive state;
• closing of a first semiconductor switch in a first phase and closing of a second semiconductor switch in a second phase;
• opening of the first and the second semiconductor switch and closing of a reversible switching device or a direct switching device in the second and a third phase;
• closing of the first and second semiconductor switch;
• closing of a first electromechanical switch in the first phase and a second electromechanical switch in the second phase that each form a bypass circuit with the first and second semiconductor switches;
• rejecting of active control of the semiconductor switches;
• wherein a fault in the motor starter is detected when during closing or opening of the first semiconductor switch a current flow is detected by at least one measuring apparatus in the first phase, the second phase, or the first phase and the second phase or when during closing of the first and second semiconductor switches a current flow of zero is detected in the first phase, the second phase, or the first phase and the second phase by the at least one measuring apparatus.

A diagnostic method for a motor starter configured as a direct starter and connected to a single-phase electric motor, the method comprising:

• providing the motor starter in an inactive state;
• closing a first phase with a first electromechanical switch;
• opening the first phase;
• closing a first semiconductor switch in the first phase and a second semiconductor switch in a second phase by active control of the first and second semiconductor switches;
• closing a first electromechanical switch in the first phase and a second electromechanical switch in the second phase that each form a bypass circuit with the first and second semiconductor switches;
• rejecting the active control of the first and second semiconductor switches;
• wherein a fault in the motor starter is detected if when closing the first phase a current flow is detected by at least one measuring apparatus in the first phase, second phase, or first and second phase when closing the first semiconductor switch in the first phase and the second semiconductor switch in the second phase a current flow of zero is detected by the at least one measuring apparatus in the first phase, second phase, or first and second phase.