Torque value

With a view to achieve yet more standardization in motor design, NEMA Standard MG-1 has also recommended the maximum locked rotor current of single-speed three-phase motors for the various rotor designs A, B, C, and D, for various recommended torque values. These have been derived for a 415 V a.c. system and are shown in Table 2.2. 

Generally, the number of steps is decided by the limits required in the maximum and minimum torque values. It is therefore not an arbitrary figure as assumed in the above example. We will, however, conclude in the next article, that the lower the limits of and T -, the higher will be the required number of steps and vice versa. 

The joints must be tightened with a torque wrench. For the recommended torque values refer to Table 29.1. 

These torque values w 11 normally require high tensile fasteners. ... 

A motor speed-torque curve for a compressor (250 to 1,000 hp or more) does not look the same as a smaller machine (10 or 20 hp) (see Figure 7-3). NEMA Standard MG-1 gives minimum locked rotor-torque values as a function of motor size at 1,800 rpm (see Table 7-2). 

The voltage drop during starting should be calculated using the speed current data, locked rotor power factor, and the distribution system con stants. Speed-torque values at this reduced voltage can be calculated, assuming that the torque varies as the voltage squared. These values are compared to driven equipment curves. 

Normal torque range — tabulated minimum value to 10% greater. Largest diameter shown for each connection is the maximum recommended tor that connection. If the connectons are used on drill collars larger then the maximum shown, irxrrease the torque values shown by 10% tor a minimum value. 

Stall Torque. From Table 4-110 the stall torque for the turbine motor with 212 stages will be twice the torque value at optimum speed. Thus the stall torque for 10 Ib/gal mud weight flow is... 

The torque values listed in Table 4-153 apply to casing with zinc-plated... 

In regard to screw threads, certain observations should be considered. First, the torque values are based on the coefficients of friction of the mating parts and can thus vary significantly. The use of any compatible lubricant that reduces friction will increase the shear and hoop stresses if the torque remains the same. Therefore, with lubricants, reduce the amount of allowable torque. 

A study on the effectiveness of the E-plastomers as impact modifiers for iPP was carried out in relation to the traditional modifier EPDM. In this study, the flow properties of the E-plastomer-iPP and EPDM-PP blends were also evaluated. The blends were analyzed by solid-state 13C-nuclear magnetic resonance (NMR) spectroscopy, microscopy (SEM), and DSC. The results showed that E-plastomer-PP and EPDM-PP blends present a similar crystallization behavior, which resulted in a similar mechanical performance of the blends. However, the E-plastomer-PP blend presents lower torque values than the EPDM-PP blend, which indicates a better processibility when E-plastomer is used as an impact modifier for iPP. 

The torque continues to increase, until there is no more signihcant rise. At this point the compound is vulcanized, and this maximum torque value is designated by the symbol Mh- The last major piece of data to be extracted is the time it takes to complete the cure, known as the cure time (t x). 

Figure 20.2 Torque value as a function of PHB content for PHB/PEN/PET ternary blends measured at 285 °C and a constant rpm of 60 using a Haake rheometer molar ratio of PEN to PET of 1 1...

A polyacetylene coating applied on sulfur does not negatively influence its activity and speed as curing agent, but it can increase the scorch time. This effect is probably due to a delayed release of the sulfur out of the polymeric shell. In the SBR/EPDM blend, on the other hand, the plasma-treated sulfur results in higher torque values, an indication that the distribution of the plasma-treated sulfur over the different rubber phases is more homogenous, which is the main effect aimed for in the context of this study. 

Nakajima and Hamel50 have derived expressions for calculating shear stresses from the Mooney torque values to give viscosities in agreement with those obtained from other instruments, and also an expression to correct for the edge effects.51 Bristow52 derived non-standard Mooney parameters for natural rubbers to improve the distinction between different grades. 

Torque requirements must also be considered. The motor must be capable of carrying the peak horsepower (torque) value from the duty cycle at 90 percent voltage. Motor breakdown torque Is reduced by the square of the voltage. The relationship Is given In Equation (5). 

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. 

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