SuperFlow AutoDyn, Руководство оператора

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M a n u a l
AutoDyn
Section 2 - Page 6
AutoDyn manual 1174 Sect ion 2. PM7, 5/2004
2.2. Components
The AutoDyn dynamometer consists of three major components. These
are the frame assembly, the sensor box, and the absorber module (if
applicable).
A more detailed description of each of these components follows.
2.3. Frame Assembly
The frame contains the rolls, roll shaft or axle, air-actuated roll
brakes, and a tachometer gear with magnetic pick-up.
The frame is boxed for improved stiffness and to achieve the most
compact design. The absorber is driven off the axle differential pinion
gear via a drive-shaft. The axle is mounted in trunnion bearings and a
load cell connects the differential to the frame. All parasitic losses are
measured by the load cell, except the windage (aerodynamic losses) of
the rolls. The windage is measured at the factory and compensated in
the software. The rolls are mounted on the axle wheel flanges and can
be removed after unbolting end plates on both sides of the frame.
The truck axle differential allows the use of different axle ratios for
different applications. The standard ratios are 2.79:1 for Eddy Current
absorbers. This selection is based on a maximum design speed of 200
mph. Other axle ratios result in different speed and power characteristics
of the dynamometer.
The rolls have a nominal diameter of 42” (106.7 cm) and are 28” (71.1 cm)
wide. They are spaced 28” (71.1 cm) apart. The inertia of the rolls is
measured by SuperFlow to provide an exact calculation of power when
the roll is accelerated. This inertia value is stored in the sensor box
electronics.
A magnetic pick-up detects the teeth on the tachometer gear. This
frequency is then converted to roll speed via the CPU printed circuit
card and the system software. The magnetic pick-up also creates a
signal that interlocks the roll brakes and lift or ramp commands (if
applicable) while the roll is rotating.
The roll brakes consist of a hydraulic disk brake installed on the
differential pinion shaft. The brakes are actuated by an air solenoid,
which must be supplied with 100 psi (690 kPa) air pressure.
An electrical interface box is mounted on the dynamometer frame. On
the dynamometer side, this interface box is wired to the load cell, the
magnetic pick-up, the roll lock solenoid, and the absorber. The interface
box groups all dynamometer data and control signals for connection to
the sensor box. The sensor box is connected with a single cable.
For above-ground installations, the dynamometer frame can be
equipped with restraint bars, which offer convenient tie-down points for
one end of the vehicle. For pit installations, tie-down points should be
embedded in the concrete floor slab.