Electrical Transformer (MBA) Lecture Review

A set of vocabulary flashcards covering the fundamental principles, components, and formulas for transformers (MBA) as described in the lecture notes.

Maximum Efficiency Condition

The condition where iron loss equals copper loss ($P_{Fe} = P_{Cu}$).

Auto-transformer (MBA tự ngẫu)

A type of transformer typically used when the voltage difference is small.

Transformation Ratio ($k$)

The ratio defined by the formula $k = \frac{U_1}{U_2}$.

No-load Current ($I_0$)

The specific current in a transformer when the secondary side is open-circuited.

$\Delta/\Delta$ Connection Group

A transformer connection configuration known as Delta-Delta (Tam giác/tam giác).

3-Phase Rated Power ($S$)

The power capacity for a 3-phase transformer calculated as $S = \sqrt{3}UI$.

Parallel Operation Conditions

The three requirements for transformers to work in parallel: same transformation ratio, same connection group, and same short-circuit voltage.

No-load Test (Thí nghiệm không tải)

An experiment conducted to determine the iron loss ($P_{Fe}$) of a transformer.

Laminated Core

A transformer core made of thin sheets to reduce eddy currents (dòng xoáy).

Frequency ($f$)

The electrical parameter that remains unchanged (không đổi) during voltage transformation.

Isolation Transformer

A transformer where the transformation ratio $k = 1$.

Main Magnetic Flux ($\Phi_m$)

The primary magnetic flux designated by the symbol $\Phi_m$ within a transformer.

$Y/\Delta$ Connection Group

A transformer connection configuration known as Wye-Delta (Sao/tam giác).

Short-circuit Test (Thí nghiệm ngắn mạch)

An experiment conducted to determine the copper loss ($P_{Cu}$) of a transformer.

Primary Winding (Cuộn sơ cấp)

The winding of the transformer that is connected to the power source (nguồn).

Secondary Winding (Cuộn thứ cấp)

The winding of the transformer that is connected to the load (tải).

1-Phase Rated Power ($S$)

The power capacity for a 1-phase transformer calculated as $S = UI$.

Electromagnetic Induction (Cảm ứng điện từ)

The physical phenomenon that forms the basis of transformer operation.

$Y/Y$ Connection Group

A transformer connection configuration known as Wye-Wye (Sao/sao).

DC (Direct Current)

The type of current with which a transformer cannot operate.

Copper Loss ($P_{Cu}$)

The loss in a transformer that depends primarily on the magnitude of the current.

Iron Loss ($P_{Fe}$)

The loss in a transformer that depends on the voltage and frequency.

Typical No-load Current Range

The current value which usually accounts for $2 \text{--} 10\%$ of the rated current ($I_{\text{đm}}$).

Step-up Transformer

A transformer designed for the condition where $U_2 > U_1$.

Step-down Transformer

A transformer designed for the condition where $U_2 < U_1$.

Ideal Transformer (MBA lý tưởng)

A theoretical transformer with no losses ($P_1 = P_2$) and $100\%$ efficiency ($\eta = 100\%$).

Transformer Core Material

Constructed using electrical steel sheets (lá thép kỹ thuật điện).

Induced Electromotive Force Formula ($E$)

The expression defined as $E = 4.44fW\Phi_m$.

Transformer Capacity Unit

The standard unit for transformer power, which is the $kVA$.

Secondary Voltage Variation ($\Delta U$)

The change in secondary voltage defined as $\Delta U = U_{20} - U_2$.

Large Capacity Core Selection

High-power transformers typically use a stepped circular (tròn bậc thang) cross-section for the core pillars.