Saturation and Hysteresis Curves Flashcards

Vocabulary flashcards covering core concepts, measurement techniques, and experimental data from Practice 4 on saturation and hysteresis curves in electrical machines.

Magnetic Domains

Microscopic internal regions within ferromagnetic materials (such as iron, nickel, and cobalt) whose magnetic moments are randomly oriented in an unmagnetized state, yielding a net magnetic field of $B = 0$.

Ideal Hysteresis Loop

A graphical representation showing the relationship between magnetic flux density $B$ and magnetic field intensity $H$ as a ferromagnetic material undergoes cyclic magnetization and demagnetization.

Magnetic Remanence ($B_r$)

The residual magnetic flux density retained within a ferromagnetic material when the applied magnetic field intensity $H$ is reduced back to zero.

Coercive Force ($H_c$)

The magnitude of the magnetic field intensity required in the opposite direction to reduce the residual magnetic flux density $B_r$ back to zero.

Hysteresis Losses ($P_h$)

Energy dissipated in the form of heat inside a magnetic core due to the continuous reorientation of magnetic domains under alternating current (AC) excitation.

Soft Magnetic Materials

Ferromagnetic materials (such as silicon steel) that exhibit a narrow hysteresis loop, minimizing energy loss per AC cycle and maximizing electrical machine efficiency.

Linear Region (Magnetization Curve)

The initial phase of magnetization starting from $(0,0)$ where magnetic flux density $B$ increases rapidly and proportionally with increases in magnetic field intensity $H$ as domains align.

Knee of Saturation

The transition zone on a magnetization curve where most magnetic domains are already aligned, causing further increases in excitation current to yield only minimal increases in flux density.

Saturation Curve (Single-Phase Transformer)

A plot of secondary step-up voltage ($V_{elevado}$) against primary excitation current ($I_{mag}$) illustrating the linear region, saturation knee, and saturation region of the core.

Auxiliary 100-Turn Coil Technique

A measurement setup using an $N = 100$ turn coil placed inside a current clamp to multiply magnetomotive force by 100 ($I_{\text{detected}} = 100 \times I_{\text{real}}$), enabling precise detection of low excitation currents ($10\,\text{mA}$ to $100\,\text{mA}$).

Fluke 39 Power Meter

A power analyzer and energy quality meter used to measure voltage, current, and power, and display real-time $V-I$ hysteresis loops during core saturation testing.

Excitation Current ($I_{mag}$)

The no-load current drawn by the primary winding of a transformer to produce the magnetic flux required for core operation, ranging from $10.00\,\text{mA}$ to $106.90\,\text{mA}$ in the experiment.