_______ brushes are fragile and cause excessive wear of commutator,

1.	_______ brushes are fragile and cause excessive wear of commutator,
A.	Natural graphite
B.	Hard carbon
C.	Electro graphitic
D.	Metal graphite
Answer» B. Hard carbon

Discussion

No Comment Found

Related MCQs

Lewis form factor for composite and full depth involute system is (where T = Number of teeth)
The Wahl's stress factor (K) for springs is given by (where )
A shaft is subjected to a maximum bending stress of 80 N/mm2 and maximum shearing stress equal to 30 N/mm2 at a particular section. If the yield point in tension of the material is 280 N/mm2 and the maximum shear stress theory of failure is used, then the factor of safety obtained will be
If P1 is the initial tension due to tightening up the bolt and P2 is the external load on the bolt, then the resultant load (P) on a bolt may be obtained by using the relation (where a = Ratio of elasticity of connected parts to the elasticity of bolt)
The permissible stress in the fillet weld is 100 N/mm2. The fillet weld has equal leg lengths of 15 mm each. The allowable shearing load on the weldment per cm length of the weld is
A compound cylinder with inner radius 50 mm and outer radius 70 mm is made by shrinking one cylinder on to the other cylinder, The junction radius is 60 mm and the junction pressure is 1.1 N/mm2. The maximum hoop stress developed in the inner cylinder is
A metal pipe of 1 m diameter contains a fluid having a pressure of 1 N/mm2. If the permissible tensile stress in the metal is 20 N/mm2, then the thickness of the metal required for making the pipe will be
The condition for maximum power transmission is that the maximum tension in the flat belt should be equal to (Where, Pc = tension in belt due to centrifugal force)
When the belt is transmitting maximum power, the belt speed should be (Where, m = mass of belt per meter (kg/m) and Pmax = maximum permissible tension in belt (N))
The machine screws are

_______ brushes are fragile and cause excessive wear of commutator,

Discussion

No Comment Found

Related MCQs

Reply to Comment