Describe why it may be dangerous and explain how it may be overcome.

1.What is the ‘stroboscopic effect’? Describe why it may be dangerous and explain

 

how it may be overcome. 2. A hospital corridor is lit by twelve 100 W GLS lamps. As an economy measure, the GLS lamps are to be replaced with SL18 integral compact-fluorescent lamps, each of which consumes 18Wand provides a similar lumen output to the 100W GLS types. If the GLS lamps have an expected life of 1000 hours at a cost of 34p each and SL18s are rated 5000 hours and cost £5.25 each, calculate the cost saving over a burning period of 10 000 hours. Ignore the savings in labour costs for lamp changing, and assume that the energy cost over the period will be 5.2p/kWh.

 

 

find the cost of your paper

Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator

1. (a) Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator: (i) series-connected, (ii) shunt-connected and (iii) compound-connected.   (b) State one purpose for which….

what happens if the resistance in series with the shunt field of a DC motor is increased in value

1. Sparking at the trailing edges of the brushes in a DC machine is usually prevented by fitting   (a) copper gauze brushes (b) a compensating winding (c) a compound….

Calculate the synchronous speed of a 10-pole three-phase machine connected to a 50 Hz supply.

1. The generator characteristic shown in Figure 9.28 is for a   (a) shunt machine (b) series machine (c) differentially compounded machine (d) cumulatively compounded machine 2.The speed of a….