Question

Part 2:

1. You are investigating the electrical testing circuits and find that, in an inductive circuit, the relationship between instantaneous current i (amps) and the time t (secs) is given by:

i = 2.1(1-e^-9t)

You have been asked to determine the time taken for the current to rise from 1 to 1.5 amps.

Comment on the time taken for the current to rise the same increment from 1.5 to 2 amps and give reasons. You are not required to evaluate this.

2. The drive system of a conveyor used to transport the engine parts is made up of an open belt which passes over two pulleys. The pulleys have diameters of 200mm and 320mm respectively and the distance between centres is 600 mm.

You have been asked to determine the length of the belt, using trigonometric techniques, assuming the belt is in tension.

3. An electrical cable is to be suspended across two machines. The machines are a distance of 4.5 metres apart. The cable takes the shape of a catenary of the form y = c cosh (x/ where x is the horizontal distance of any given point on the catenary from its centre and y is it’s height from the ground surface. You have been asked to determine the fixing point height (y) if the minimum clearance (c) is to be 3m at the centre of the catenary.

Answer 1