Synchronous Speed

n_s = 120 × f / p, where f is frequency (Hz) and p is number of poles.

Slip

s = (n_s − n) / n_s × 100%, where n is rated RPM. Typical slip: 2–5% for standard motors.

Torque

T = P × 9550 / n (Nm), where P is power in kW and n is RPM.

Efficiency

η = P_out / P_in = P / (√3 × V × I × cos φ). Can be estimated from nameplate data.

Insulation Classes

Class	Max Winding Temp	Ambient + Rise + Hotspot
A	105°C	40 + 60 + 5°C
E	120°C	40 + 75 + 5°C
B	130°C	40 + 80 + 10°C
F	155°C	40 + 105 + 10°C
H	180°C	40 + 125 + 15°C

IE Efficiency Classes (IEC 60034-30-1)

Class	Level	Typical η (11 kW, 4p)
IE1	Standard	~87.6%
IE2	High	~89.4%
IE3	Premium	~91.4%
IE4	Super Premium	~92.6%
IE5	Ultra Premium	~93.9%

IP Rating Explanation

IP stands for Ingress Protection. First digit = solids protection (0–6), second digit = water protection (0–9).

• IP55 — Dust-protected, protected against water jets from any direction
• IP65 — Dust-tight, protected against water jets
• IP66 — Dust-tight, protected against powerful water jets