The periodic operating conditions – starting, driving, braking – can be recorded on an operating graph representing the motor torque versus the driving time. The cubic mean of the motor torque and an average speed, which is also determined from the operating graph taper roller bearing , form the basis for the rolling bearing analysis. The mean torque is about 90 % of the torque at constant power. The bearing loads are calculated as for traction motors for standard-gauge locomotives (example 1). They are made up of the reaction loads resulting from the gear force on the driving pinion and a theoretical radial load which takes into account the rotor weight, the magnetic pull, unbalanced loads and rail shocks. This theoretical radial load applied at the rotor centre of gravity is calculated by multiplying the rotor weight by the supplementary factor fz = 2. The value 2 takes into account the relatively rigid motor suspension. An overhung pinion provides the drive. A...
