Electrical Machine Design

The input impedance of a JFET is _____________that of an ordinary transistor?

Byadmin December 22, 2018August 11, 2021

The input impedance of a JFET is _____________that of an ordinary transistor?

A. equal to
B. less than
C. more than
D. none of the above

Electrical Machine Design

___________ brushes are fragile and cause excessive wear of commutator?

___________ brushes are fragile and cause excessive wear of commutator?

A. Natural graphite
B. Hard carbon
C. Electro graphitic
D. Metal graphite

Read More ___________ brushes are fragile and cause excessive wear of commutator?
Electrical Machine Design

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is__________________?

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is__________________?

A. 1 + 0.2 kVmm
B. 2 + 0.5 kVmm
C. 4 + 0.7 kV mm
D. 5 + 0.9 kV mm

Read More A practical formula for determining the thickness of insulation between low voltage and high voltage windings is__________________?
Electrical Machine Design

In _________ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft?

In _________ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft?

A. small
B. medium
C. large
D. any of the above.

Read More In _________ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft?
Electrical Machine Design

A current density of __________ is ilsed for large power transformers with forced circulation of oil or with water cooling coils?

A current density of __________ is ilsed for large power transformers with forced circulation of oil or with water cooling coils?

A. 1.5 to 2.5 A/mm2
B. 3.5 to 4.5 A/mm2
C. 4.0 to 5.0 A/mm2
D. 5.4 to 6.2 A/mm2

Read More A current density of __________ is ilsed for large power transformers with forced circulation of oil or with water cooling coils?
Electrical Machine Design

The thermal conductivity of hydrogen is _____________ times that of air?

The thermal conductivity of hydrogen is _____________ times that of air?

A. 2
B. 3
C. 5
D. 7

Read More The thermal conductivity of hydrogen is _____________ times that of air?
Electrical Machine Design

In D.C. machines, the ________ in field mmf results in increase in size and cost of machines?

In D.C. machines, the ________ in field mmf results in increase in size and cost of machines?

A. increase
B. decrease
C. either of the above
D. none of the above

Read More In D.C. machines, the ________ in field mmf results in increase in size and cost of machines?

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