Related Questions

The radius of a friction circle for a shaft rotating inside a bearing is (where r = Radius of shaft and $$\tan \varphi $$  = Coefficient of friction between the shaft and bearing)
A $${\text{r}}\sin \varphi $$
B $${\text{r}}\cos \varphi $$
C $${\text{r}}\tan \varphi $$
D $$\frac{{\text{r}}}{2}\cos \varphi $$
Two shafts A and B are made of the same material. The diameter of shaft A is twice as that of shaft B. The power transmitted by the shaft A will be __________ of shaft B.
A Twice
B Four times
C Eight times
D Sixteen times
Blocked rotor test on induction motors is used to find out
A Leakage reactance
B Power factor on short circuit
C Short-circuit current under rated voltage
D All of the above
In three-phase induction motors sometimes copper bars are placed deep in the rotor to
A Improve starting torque
B Reduce copper losses
C Improve efficiency
D Improve power factor
In squirrel cage induction motors, the rotor slots are usually given slight skew in order to
A Reduce windage losses
B Reduce eddy currents
C Reduce accumulation of dirt and dust
D Reduce magnetic hum
The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it
A improves the efficiency
B helps the rotor teeth to remain under the stator teeth
C helps in reducing the tendency of the rotor teeth to remain under the stator teeth
D improves the power factor
A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is
A Slop speed operation
B High starting torque
C Low windage losses
D All of the above
The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft and $$I$$ = Mass moment of inertia of the disc attached at the end of a shaft)
A $$2\pi \sqrt {\frac{{\text{q}}}{I}} $$
B $$2\pi \sqrt {{\text{q}}I} $$
C $$\frac{1}{{2\pi }}\sqrt {\frac{{\text{q}}}{I}} $$
D $$\frac{1}{{2\pi }}$$
The product of the tangential force acting on the shaft and its distance from the axis of the shaft (i.e. radius of shaft) is known as
A Bending moment
B Twisting moment
C Torsional rigidity
D Flexural rigidity
The property of a bearing material which has the ability to accommodate shaft deflections and bearing inaccuracies by plastic deformation without excessive wear and heating, is known as
A Bondability
B Embeddability
C Comformability
D Fatigue strength

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