Mechanical Losses

The user can specify drive train mechanical losses where necessary. Either use Expressed as torque to specify a loss torque in kNm or select Expressed as power to specify a power loss in kW. In either case losses are referred to the low-speed shaft. The user must enter a lookup table by clicking the appropriate Add button(s) as required. This may be a simple lookup table on shaft speed or on shaft torque or power (depending on the option selected), or a two-dimensional lookup table on shaft speed and either torque or power. If a lookup table is used, loss values will be linearly interpolated from the table.

The option to express losses in terms of power has been provided for convenience, since data is sometimes provided in this form. However this model is inappropriate at low rotational speeds. If any calculations at low-speed are to be carried out, including start-ups, shut-downs, idling, or parked simulations with slipping brake, then it is advisable to recalculate the losses in terms of torque.

In the Bladed model, the mechanical losses are applied as friction at the position of the shaft brake. If the brake is on the high-speed shaft, the loss torque is scaled appropriately using the gearbox ratio.

When using an external gearbox DLL, the mechanical losses defined in the user interface are not applied and should be applied in the DLL if required.

Last updated 10-09-2024