Codes: Course Content
Codes: Course Content
Codes: Course Content
Codes
Course Content
• There is a relation between these 3 types of torques which differs between motor and
generator [Breaking motor = generator].
Te α ΦI Td
Driving
Mn Gn torque
TL Te
Mechanical load Electrical load
TF TF
Te = TL + Tf Td = Te + Tf
k.Φ.I = TL + Tf Te α I
@ No Load: @ No Load:
TL = 0 Te = Tf I (Decreases) Te = 0 Td = Tf
- Notes:
Sometimes it’s not recommended the operation @ max ɳ
In problems: An induction motor 10 kW, ….. etc
10 kW Rated power
Power calculated ≈ Rated power
𝑑𝜔
𝑇𝑒 = 𝐽 + 𝐵. 𝑊 + 𝑇𝐿
𝜕𝑡
2𝜋𝑛
𝜔=
60
𝒓𝒂𝒅 𝒓𝒆𝒗
𝝎 − −→ ( ) & 𝒏 − −→ (𝐦𝐢𝐧)
𝒔
𝒅𝝎
𝑱 𝝎′ = 𝜽′′
𝝏𝒕
𝐵. 𝑊 = 𝑇𝑓 (𝐹𝑟𝑖𝑐𝑡𝑖𝑜𝑛 − 𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡)
1. Fan loads
(T α w2, it constant depend on fan time)
2. Constant torque loads
(T = Constant), P = T w
P α W at T Constant
Example :. Pump, Compressor, Elevator