TMF ROAD — traction induction motor for e-buses and trolleybuses 240–427 kW

Technical specifications

Specifications are taken from the manufacturer’s technical documentation. Updated 11/06/2026.

Description

This is a three-phase induction motor with a copper squirrel-cage on the rotor. Cooling is by air with forced ventilation, the insulation is class R (220 °C), the bearing assembly is designed for an extended lifetime, and the housing is tuned for noise level. The protection degree is IP20 for the motor and IP65 for the terminal box per ISO 20653. The motor works with inverters of different types, and different winding versions are possible. The DC link has a voltage of 600–900 V, and the maximum rotational speed is 4800 rpm. The TMF 35-44-4 version is used on 18-metre articulated buses operating in more than 20 countries, and TMF 37-21-4 and TMF 35-28-4 are fitted on ordinary and hydrogen buses. According to the manufacturer, more than 2600 of its bus motors are in operation on the roads. The motors are made in Europe, designed and tested at the company's own test bench in Wiener Neudorf, and may meet Buy America requirements.

How to choose

The size is chosen by peak and continuous power and torque. TMF 37-21-4 (Medium Duty) gives 240 kW peak and 180 kW continuous, torque 1800 / 843 N·m and a weight of 305 kg. TMF 35-28-4 (Medium Duty) has 276 / 212 kW, 1800 / 1100 N·m and 350 kg. TMF 35-44-4 (Heavy Duty) develops 427 / 308 kW, 2800 / 1600 N·m at a weight of 480 kg. For the final selection, driving cycle data and traction calculations are provided, from which energy consumption and winding temperatures are determined. If you need magnets and a lower weight, consider the synchronous TMPW with a power of 217–550 kW.