A test bench for screwdrivers comprises a hydraulic brake unit (11) provided with a coupling (12) for a screwdriver to be tested and angle and torque measurement transducers (15). The brake unit (11) comprises a disk (40) axially connected to the coupling (12) so as to be rotated by a screwdriver to be tested, and braking plates (42, 43) pushed in a controllable manner with their braking surfaces (44, 45) against the disk (40) by means of a plurality of pistons (46, 47) supplied with fluid by an electrovalve (16). The pistons (46, 47) of the plurality can be selectively activated under the control of the control unit (26) so as to select a maximum braking torque of the brake. The control may be performed by means a PID controller (19) which receives an electrovalve control signal (22) from a control unit (26) so as to follow braking curves depending on the angle of rotation and/or torque measured and has parameters which can be set using different sets of parameters. A method for controlling the bench is also described.

Turbomachines such as air dynamometers are disclosed that include a radial outflow compressor and gas collector. In some examples, the gas collector is designed as a separate component that is coupled to the machine, such as coupled to a frame. In some examples, the collector and frame are intentionally spaced and coupled at discrete points to minimize the transfer of mechanical and thermal energy therebetween. Aspects of the present disclosure also include turbomachines that include at least one impeller bypass flow path for the direct transfer of air between ambient and a location in the collector downstream of the impeller blades. In some examples, such flowpath(s) may allow for the inflow of external ambient air into the collector.

A hydrodynamic-type hydraulic dynamometer is provided. The hydrodynamic-type hydraulic dynamometer includes a shaft rotatably mounted by a plurality of bearings, a stator fixed around the shaft and having a toroidal chamber therein, a runner rotatably coupled to the shaft and causing a fluid introduced into the toroidal chamber to flow therethrough, an inner ring mounted to extend inwardly from a radially outer side of the toroidal chamber and having a control slit formed therethrough, and a shutter configured to adjust an opening degree of the control slit.

A hydrodynamic-type hydraulic dynamometer is provided. The hydrodynamic-type hydraulic dynamometer includes a shaft rotatably mounted by a plurality of bearings, a stator fixed around the shaft and having a toroidal chamber therein, a runner rotatably coupled to the shaft and causing a fluid introduced into the toroidal chamber to flow therethrough, an inner ring mounted to extend inwardly from a radially outer side of the toroidal chamber and having a control slit formed therethrough, and a shutter configured to adjust an opening degree of the control slit.

An improved prony brake dynamometer capable of measuring the power of a prime mover's rotating shaft connected to a cylinder brake drum rotating around a newly designed dual quad power stator (DQPS), with hydraulic pressure equalizer plate (HPEP), controlled by an electronic load control system with inline cooling system (ELCS), cooled by a 270-degree water distribution manifold (WDM). The improvements of the DQPS and HPEP result in maximizing the pressure applied by the stator over the entire surface area of the rotor drum, thereby maximizing the coefficient of friction at the kinetic point of energy and increasing load capacity over previous models. The addition of the ELCS increases the number of potential settings of hydraulic pressure, resulting in thousands of power settings, as opposed to previous models using manual load control valves. The WDM cools the dynamometer load absorption unit more efficiently than previous models.

An improved prony brake dynamometer capable of measuring the power of a prime mover's rotating shaft connected to a cylinder brake drum rotating around a newly designed dual quad power stator (DQPS), with hydraulic pressure equalizer plate (HPEP), controlled by an electronic load control system with inline cooling system (ELCS), cooled by a 270-degree water distribution manifold (WDM). The improvements of the DQPS and HPEP result in maximizing the pressure applied by the stator over the entire surface area of the rotor drum, thereby maximizing the coefficient of friction at the kinetic point of energy and increasing load capacity over previous models. The addition of the ELCS increases the number of potential settings of hydraulic pressure, resulting in thousands of power settings, as opposed to previous models using manual load control valves. The WDM cools the dynamometer load absorption unit more efficiently than previous models.

Turbomachines such as air dynamometers are disclosed that include a radial outflow compressor and gas collector. In some examples, the gas collector is designed as a separate component that is coupled to the machine, such as coupled to a frame. In some examples, the collector and frame are intentionally spaced and coupled at discrete points to minimize the transfer of mechanical and thermal energy therebetween. Aspects of the present disclosure also include turbomachines that include at least one impeller bypass flow path for the direct transfer of air between ambient and a location in the collector downstream of the impeller blades. In some examples, such flowpath(s) may allow for the inflow of external ambient air into the collector.

Disclosed herein are various dynamometer embodiments in which the devices have a cooling tank comprising cooling fluid, a rotatable drum body disposed over a stator body, and first and second friction disks axially extendable from the stator body such that the friction disks are frictionally engageable with the bases of the drum body. The bases of the drum body can be rotatable friction plates that are coupled via a connection tube to form the drum body.

Disclosed herein are various dynamometer embodiments in which the devices have a cooling tank comprising cooling fluid, a rotatable drum body disposed over a stator body, and first and second friction disks axially extendable from the stator body such that the friction disks are frictionally engageable with the bases of the drum body. The bases of the drum body can be rotatable friction plates that are coupled via a connection tube to form the drum body.

Disclosed herein are various dynamometer embodiments in which the devices have a cooling tank comprising cooling fluid, a rotatable drum body disposed over a stator body, and first and second friction disks axially extendable from the stator body such that the friction disks are frictionally engageable with the bases of the drum body. The bases of the drum body can be rotatable friction plates that are coupled via a connection tube to form the drum body.