Torque output

In general, the larger lobe profile number ratios of a positive displacement motor, the higher the torque output and the lower the speed (assuming all other design limitations remain the same). 

Total Pressure Loss. Since bit life is not an issue in a short deviation control motor run operation, it is desirable to operate the positive displacement motor at as high a power level as possible during the run. The motor has a maximum pressure loss with which it can operate. This is 580 psi (see Table 4-114). It will be assumed that the motor will be operated at the 580 psi pressure loss in order to maximize the torque output of the motor. To obtain the highest horsepower for the motor, the highest circulation flowrate possible while operating within the constraints of the surface mud pump should be obtained. To obtain this highest possible, or optimal, circulation flowrate, the total pressure losses for the circulation system must be obtained for various circulation flowrates. These total pressure losses tabulated in the lower row of Table 4-117 represent the surface standpipe pressure when operating at the various circulation flowrates. 

Although not a design that guarantees positive power transmission, a satisfactorily performing friction clutch will transmit the maximum torque output of the driver to the driven shaft without slip when fully engaged. The automobile clutch is the most common example, transmitting the maximum motor torque to the wheels. 

MINIMUM TORQUE OUTPUT W/FULL 11 GFAR RATIO... 

The torque outputs for several pneumatic actuators at several different supply pressures are given in the table below. 

Figure 3-13 Vane Yield Stress Setup at Controlled Strain Qiu and Rao (1988). The Numbers Denote Separate Pieces of Equipment 1—torque unit, 2—vane, 3—constant temperature vessel for sample, 4— constant temperature bath, 5—viscometer drive motor, 6—viscometer control panel, 7—chart recorder for torque output, and 8— voltmeter to monitor vane rpm signal.

The engine torque output was measured by a prony brake mounted on another platform scale, and the engine RPM by hand tachometer. The brake horsepower output in each run was thus determined. 

MINIMUM torque Output w/full 1 GEAR RATIO... 

Tan, J.C., Parnianpour, M., and Nordin M. et al. 1993. Isometric maximal and submaximal trunk exertion at different flexed positions in standing triaxial torque output and EMG. Spine 18 2480. 

Estimate the net torque output of the ei ine from the followup equation ... 

Some of the factors that engfneets consider when selecting a motor for an application are (a) motor type, (b) motor speed (rpm), (c) motor performance in terms of torque output, (d) efficiency, (e) duty cycles, (f) cost, life eaqpectancy, (h) noise level, (i) maintenance and service requirements. Most of these are sdfeaqjlanatoiy. We discussed speed and torque in previous chapters next we will discuss motor types and duty cycles. 

Synchronous motors are physically smaller for the same torque output. 

As a rule of thumb, a power shaft running under no load at the MOR can be expected to have a useful life in excess of 10 revolutions. Such factors as service temperature, number of shaft bends, torque output, speed, shock loading, and operating radius can reduce shaft life. 

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