Ergometer

Ergometer

An ergometer consists of an absorption (or absorber/driver) unit, and usually includes a means for measuring torque and rotational speed. An absorption unit consists of some type of rotor in a housing. Some means is provided to develop a braking torque between ergometer’s rotor and housing. The means for developing torque can be frictional, hydraulic, electromagnetic etc. according to the type of absorption/driver unit.

One means for measuring torque is to mount the ergometer housing so that it is free to turn except that a torque arm restrains it. The housing can be made free to rotate by using trunnions connected to each end of the housing to support the ergo in pedestal mounted trunnion bearings. The torque arm is connected to the ergo housing and a weighing scale is positioned so that it measures the force exerted by the ergo housing in attempting to rotate. The torque is the force indicated by the scales multiplied by the length of the torque arm measured from the center of the ergometer.

Another means for measuring torque is to connect the engine to the ergometer through a torque sensing coupling or torque transducer. A torque transducer provides an electrical signal that is proportional to torque.

With electrical absorption units, it is possible to determine torque by measuring the current drawn (or generated) by the absorber/driver. A wide variety of tachometers are available for measuring speed. Some types can provide an electrical signal that is proportional to speed.

When torque and speed signals are available, test data can be transmitted to a data acquisition system rather than being recorded manually. A chart recorder or plotter can also record speed and torque signals.