Electrical Machines - Basic Vocational Knowledge (IBE - Deutschland; 144 pages) Introduction 1. General information about electrical machines 2. Basic principles 2.1. The magnetic field 2.1.1. Definition and presentation of the magnetic field 2.1.2. Magnets Magnetic field 2.1.3. Magnetic field of a current-carrying conductor 2.1.4. Magnetic field of a current-carrying coil 2.1.5. Magnetic fields in electrical machines 2.2. Measurable variables of the magnetic field 2.3. Force action of the magnetic field 2.4. Voltage generation through induction 3. Execution of rotating electrical machines 4. Synchronous machines 5. Asynchronous motors 6. Direct current machines 7. Single-phase alternating current motors 8. Transformer

#### 2.1.3. Magnetic field of a current-carrying conductor

Presentation of the magnetic field

Figure 5 presents the magnetic field of a current-carrying conductor.

Figure 5 - Magnetic field of a current-carrying conductor.

1 Current flow direction

Stipulations for current presentation

- Where the current flows away from the viewer, that is to say into the paper plane, a cross is indicated in the conductor cross-section.

- Where the current flows towards the viewer, that is to say out of the paper plane, a dot is entered into the conductor cross-section.

Figure 6 - Current direction designation in the plane of field lines

Direction of field lines

As Figure 6 indicates the direction of the magnetic field lines depends on the current direction. If one views the conductor cross-section in current direction, then the field lines appear clockwise.

If one clamps such a current-carrying conductor with one’s fist so that the projecting thumb points in current direction, then the bent fingers indicate the direction of the field lines.