Watertight Propeller Dynamometer

Product Description

Watertight Propeller Dynamometer

The Watertight Propeller Dynamometer of high capacity is sealed against pressure of up to 1 bar above atmospheric pressure and against relatively high vacuum (1 bar = 10 to the power 5 N/m2 = 0.1 MPa).It is thus suitable for use in the measuring section of cavitation tunnels, as an inner drive dynamometer in ship models or in dummy bodies mounted in the measuring section of a cavitation tunnel. The dynamometer can be used also for propulsion tests with relatively high torque and thrust values in ship models under water. That has slightly larger dimensions, but is of similar appearance.Idle friction of the measuring shaft is small despite the use of sealing rings and is approximately 0.3 Nm for dynamometer and 0.4 Nm for dynamometer

Specification of Watertight Propeller Dynamometer

• Rated torque ±80 Nm
• Rated thrust ±2.2 kN
• Overload in torque and thrust permitted for a short moment  30%
• Maximum constant speed in water 4500 rpm
• Measuring system for torque and thrust measurement  full bridge strain gauge type
• Input resistance of the full bridge for thrust and torque measurement (supply diagonal)  about 256 ©
• Output resistance of the full bridge about 240 ©
• Recommended supply voltage for thrust and torque measurement (do not use constant current)  d.c. or a.c. up to 8 V
• Maximum supply voltage for thrust and torque measurement 20 V
• Sensitivity at rated load for thrust and torque measurement  about 1.5 mV/V
• Corresponding to an apparent strain at rated load of  about 3000 /m
• Pulse generator for speed measurement  60 pulses/1rev.
• Air pressure for brush lifting, above atmospheric pressure  1.2 0.2 bar
• Weight without cables, about 11.3 kg
• Material of the casing  stainless steel(Cr-Ni-type) and Plexiglas
• Material of the shaft ends stainless steel(Cr-type)
• 1 bar = 10 to the power 5 N/m2 = 0.1 MPs