NABTEB

LIST THREE advantages of semi conductors – NABTEB QUESTION

1. Power consumption is low 2. Require less voltage for operation 3. Cheap 4. It generates less heat 5. Long…

4 years ago

Define Semiconductor – NABTEB QUESTION

1. A semiconductor is a substance which has resistivity (10^-4 to 0.5Ωm) in between conductors and insulators e.g. germanium, silicon,…

4 years ago

State two possible observations for a worn-out ball bearings. – NABTEB QUESTION

The possible observations for worn-out ball bearings are: (i) Broken balls. (ii) Undue Noise. (iii) Dry Lubricant. (iv) Low Grease…

4 years ago

State the causes of sparking on commutator. – NABTEB QUESTION

The causes of sparking of commutator segments are: (i) Shorted armature. (ii) High Mica. (iii) Worn-out Brushes. (iv) Dirty Commutator.…

4 years ago

Explain the undercutting of a commutator. – NABTEB QUESTION

Under cutting of a commutator is defined as the reduction of mica protrusion between commutator segments using a saw blade/cutting…

4 years ago

Define the term “armature reaction”. – NABTEB QUESTION

Armature reaction is defined as the distortion of the main field due to the current flowing in the armature conductor.

4 years ago

State the tool with which to measure the S.W.G. of a winding conductor. – NABTEB QUESTION

The tool to measure the S.W.G. of a winding conductor is a “Micrometer” screwguage.

4 years ago

Explain the effects of replacing a winding with a wrong wire guage. – NABTEB QUESTION

(i) Overheating and burning of winding coils. (ii) Speed would be affected (iii) Inability of the machine to carry load.…

4 years ago

State the functions of FIVE tools used for winding. – NABTEB QUESTION

i. Spanner: Used for tightening/loosening of nuts and bolts. (ii) Scissors: Used for cutting insulators and sleeves, wires or plyboard…

4 years ago

Explain the procedures for overhauling a motor in electrical winding workshop – NABTEB QUESTION

The procedure for overhauling a motor in electrical winding workshop is as follows: (i) Dismantle the motor carefully. (ii) Clean…

4 years ago