All Nameplate Parameters Explained
| Parameter | Meaning | Typical values |
|---|---|---|
| kW (or HP) | Rated shaft output power at full load | 0.12 kW to 1,000+ kW |
| V (Voltage) | Rated supply voltage — may show dual voltage e.g. "230/400V Δ/Y" for star-delta connection | 230V, 400V, 690V (IEC) |
| A (Current) | Full-load current at rated voltage | Calculated from kW/(√3 × V × cos φ × η) |
| RPM (n) | Synchronous speed minus slip — actual shaft speed at rated load | 2-pole: ~2,950 rpm; 4-pole: ~1,450 rpm; 6-pole: ~960 rpm at 50 Hz |
| Hz (Frequency) | Rated supply frequency | 50 Hz (EU/UK/Asia), 60 Hz (Americas) |
| cos φ (PF) | Power factor at full load | 0.75–0.92 typical for induction motors |
| η or Eff. | Efficiency at full load, rated voltage | 80–97% depending on kW and IE class |
| Ins. Cl. | Winding insulation temperature class | B, F (most common), H |
| Temp. rise | Maximum temperature rise above ambient at full load | Class B: 80°C; Class F: 105°C |
| IP (Ingress Protection) | Enclosure protection against solids and liquids (IEC 60529) | IP55 (most common industrial), IP65, IP23 |
| IE | International efficiency class | IE2, IE3, IE4 |
| S.F. | Service factor — overload multiplier | 1.0, 1.15 (most common), 1.25 |
| Frame (IEC) | Mounting dimensions per IEC 60072 — shaft height, mounting holes, shaft diameter | IEC 80, 90, 100, 112, 132, 160, 180, 200, 225, 250, 280, 315… |
| Duty cycle (S) | Operating duty — continuous, intermittent, etc. | S1 (continuous), S2–S9 (intermittent/cyclic) |
| Amb. Temp. | Maximum ambient temperature for rated operation | 40°C standard; 50°C or 60°C for high-ambient variants |
| Altitude | Maximum altitude for rated operation (affects cooling) | 1,000 m standard; derate above this |
IP Ratings Decoded
IP (Ingress Protection) rating format: IP[solid digit][liquid digit]
| Solid digit | Protection against | Liquid digit | Protection against |
|---|---|---|---|
| 4 | Objects >1 mm diameter (tools, wire) | 4 | Splashing water from any direction |
| 5 | Dust protected (limited dust ingress) | 5 | Water jets from any direction |
| 6 | Dust tight (no ingress) | 6 | Powerful water jets |
| — | — | 7 | Temporary immersion up to 1 m |
| — | — | 8 | Continuous immersion (manufacturer specified) |
IP55 (most common industrial motor): dust-protected, water-jet resistant. Use IP65 in washdown areas; IP23 in dry, clean motor rooms where ventilation is important.
Dual Voltage and Star/Delta Connection
A nameplate showing "230/400V Δ/Y" means:
- Connect in delta (Δ) for 230V supply — each winding across 230V
- Connect in star (Y) for 400V supply — each winding across 230V (400V/√3)
Both connections apply the same voltage across each winding. The rated current shown is for the star (400V) connection. In delta at 230V, line current is √3 higher.
Never connect a 400V-only motor (single voltage, no delta option) to a 230V supply — it will run at very low torque and overheat. Always verify supply voltage matches nameplate voltage before energising.