Three-Phase Squirrel Cage Induction Motors

Overview

Three-Phase Industrial Induction Motors

Three-phase squirrel cage induction motors are the workhorses of industrial production. Nairobi Power Engineers stocks and supplies high-performance three-phase induction motors in frame sizes from IEC 71 (0.37 kW) up to IEC 355 (315 kW) in 2-pole (3000 RPM), 4-pole (1500 RPM), 6-pole (1000 RPM), and 8-pole (750 RPM) speeds.

Manufactured with high-purity copper stator windings, low-loss electrical steel laminations, and heavy cast iron frames, our three-phase motors deliver smooth running, high starting torque, and dependable continuous duty (S1) under tropical ambient conditions.

Product Lineup

Equipment & Range Highlights

Cast Iron Frame • 11 kW to 315 kW

Cast Iron Heavy-Duty Three-Phase Motors

Rigid cast iron frame motors engineered for heavy shock loads, crushing plants, mining conveyors, and severe industrial environments.

FrameCast Iron (Frame 160–355)

DutyContinuous S1 Duty

BearingsRegreasable SKF/FAG

Aluminium Frame • 0.18 kW to 15 kW

Aluminium Lightweight Multi-Mount Motors

Lightweight aluminium body motors with detachable multi-mount feet (B3, B5, B14) allowing easy repositioning of terminal boxes.

FrameDie-Cast Aluminium (Frame 56–132)

Weight40% Lighter than Cast Iron

Terminal BoxRotatable 90° Increments

Motor Frame Reference

3-Phase Motor Output & Speed Table (4-Pole 1500 RPM)

Frame Size	Output Power (kW / HP)	Full Load Current (400V)	Nominal Torque (Nm)
IEC 71	0.37 kW (0.5 HP)	1.1 A	2.5 Nm
IEC 90S	1.1 kW (1.5 HP)	2.7 A	7.4 Nm
IEC 100L	3.0 kW (4.0 HP)	6.5 A	19.9 Nm
IEC 132M	7.5 kW (10 HP)	15.2 A	49.1 Nm
IEC 160L	15.0 kW (20 HP)	28.9 A	97.8 Nm
IEC 225M	45.0 kW (60 HP)	82.0 A	290.5 Nm
IEC 280M	90.0 kW (120 HP)	158.0 A	581.0 Nm
IEC 355L	250.0 kW (335 HP)	430.0 A	1615.0 Nm

Key Features

Engineering & Build Highlights

Dual voltage connection: 230V Delta / 400V Star (up to 3 kW) & 400V Delta / 690V Star (4 kW and above)
High starting torque ratio (Tk/Tn ≥ 2.2) enables smooth breakaway on loaded machines
Class F insulation with Class B temperature rise ensures extra thermal margin in hot plantrooms
IP55 dust and water jet protection with oil seals fitted on drive-end and non-drive-end shafts
Dynamically balanced rotors (Grade G2.5 per ISO 1940) eliminate vibration and extend bearing life
Compatible with Lovato DOL, Star-Delta, soft starters, and variable frequency drives

Applications

Target Applications & Sectors

Centrifugal water booster & borehole pump setsIndustrial exhaust fans, blowers & cooling towersTea processing dryers, rollers & sorting screensAggregate conveyors & vibrating screensGrain milling hammer mills & roller flour millsFactory air compressors & hydraulic power packs

FAQs

B3 is standard foot-mounted; B5 is a large flange with unthreaded clearance holes (attaches to gearboxes or pump housings); B14 is a smaller face flange with threaded blind holes.

To reverse rotation, simply swap any two of the three incoming supply phase conductors (e.g. swap L1 and L2) at the motor terminal block or starter contactor.

Three-Phase Induction Motors