Speed-torque tests

Test for speed-torque and speed-current curves 11/257... 

It is therefore necessary to take precautions during the test to avoid a excessive temperature rise and consequent damage to the windings. For wound rotor motors, speed-torque and speed-current tests may be taken between synchronous speed and the speed at which the maximum torque occurs. 

Let s start with a 10 HP, 6" nominal diameter by 1" wide rotor, 1750 rpm test unit, like those shown in Figure 10.20, producing 5gpm of product. The torque requirement of the test unit is T = P/2ttN = (5)550/(2rr29.2) = 15.5 ft Ibf. What is the speed, torque, HP, and product capacity of an 18" diameter by 3" wide rotor plant unit ... 

Figure 14.18 shows the engine speed, torque, and SCR temperatures during the US06 test cycle conducted on a diesel engine motoring dynamometer setup. The ammonia coverage ratios of the two catalysts are shown in Rg. 14.19. The desired values of, and j were set to 0.3 and 0.6, respectively. 

There have been a number of developments of the Mooney test. The generally useful and accepted one has been the Delta Mooney test, which has achieved the status of an ASTM test, and is well recognized within the industry. Other techniques which have been reported are Mooney recoil, initial Mooney torque peak (PMT), and variable-speed Mooney tests. 

The Nametre Rotary B rotational viscometer measures torque in terms of the current needed to drive the d-c motor at a given speed while a material is under test. The standard sensors are coaxial cylinders or Brookfield disk-type spindles, but a cone—plate system is also available. The viscosity range for the coaxial cylinder sensors is 5 to 5 x 1(T mPa-s, and the maximum shear rate is 200. ... 

D. Performance characteristics. (Usually includes following electrical characteristics efficiency, power-factor, locked rotor KVA, fullload speed, temperature rise and starting, break-down, and full-load torques.) Be sure to advise whether special test certification is to be furnished this always extends delivery time and increases cost. 

Laboratory rotors have been used to evaluate the drag resistance of immersed surfaces as well. The rotational frequency of the innermost cylinder is adjusted to the relevant speed (monitored by a tachometer) and after about 30 minutes of flow stabilisation a 50 Nm strain gauge transducer picks up the torque, M,. All measurements are based on the average of three replicate tests. A sketch of the set-up is shown in Figure 13 details on the set-up and calculations are described in Weinell et al. (2003). 

Three types of mixer are recognized, plus a miniature mixer which would provide just enough compound for a curemeter test and one sheet. Mixers types A] and A2 and the miniature device have non-interlocking (tangential) rotors whilst type B has interlocking rotors. Dimensions of the larger mixers are specified fairly precisely, including new and worn rotor clearances, and they are required to have temperature control, a system to record power or torque and a timer. The miniature mixer is only specified in terms of capacity, rotor speed and friction ratio but is required to control of temperature, indication of power and a timer. 

Since the apparent viscosity of a non-Newtonian fluid holds only for the shear rate (as weii as temperature) at which it is determined, the Brookfield viscometer provides a known rate of shear by means of a spindle of specified configuration that rotates at a known constant speed in the fluid. The torque imposed by fluid friction can be converted to absolute viscosity units (centipoises) by a multiplication factor. See viscosity, shear stress. The viscosities of certain petroleum waxes and wax-polymer blends in the molten state can also be determined by the Brookfield test method ASTM D 2669. 

Related Calculations. When considering whether tip speed or torque per volume was the preferred method of scaleup for this example, pilot-scale results were not available to suggest possible differences. Some simple comparisons, using different size impellers in the pilot scale, may give better insight into the process behavior. For instance, instead of making all of the tests with two 6-in (0.15-m) diameter impellers, additional tests could have been made with two 7-in (0.18-m) diameter impellers. 

Data collection were correlated with viscosity, time, thermocouple temperature, and rheometer torque. The rotation speed of the rheometer was adjusted so that torque value fell between 80% to 100%. The gel formation time was defined as the time needed for a sample to increase its viscosity up to 10000 cP from its starting viscosity. Viscosity testing results are provided in Table 1. 

The input speed to the gear train was varied from 1500 to 4500 rpm, the torque from 0.025 to 0.5 Nm, and the contact load on the idler gears from 0.5 to 30N. The peripheral speeds of the gears were up to 3.3 ms , the relative slip 1 ms and the maximum contact stress 900 MPa. The test temperature was varied between 20°C and 250 C, and the chamber pressure was 10 Torr. 24 lubricating gears containing different proportions of copper, silver and molybdenum disulphide were tested, and the best performance was given by a composite of 87% copper, 5% silver and 8% molybdenum disulphide. 

The apex of a cone is brought into close proximity, but not in to contact, of a horizontal plate (Figure 3-7). Often, the apex is truncated slightly to eliminate a sharp point. The minimum gap between the cone and plate is usually of the order of 50 xm so that this geometry may not be suitable for dispersions containing larger diameter solids. The test fluid fills the gap between the cone and the plate, and because the gap is small, only a small volume (typically, 1-5 mL) of fluid is needed. The cone is rotated and the torque is measured at various speeds of rotation. A cone and plate viscometer can be used to obtain shear stress-shear rate curves and shear-stress versus time at constant shear rate curves as described above for concentric cylinder geometry. The... 

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