Transcript Fuses

17 July 2015
Fuses and Circuit Breakers
Objectives
To understand how fuses and circuit breakers
work.
HSW: AF2 – Understanding the applications and implications of
science
Used before in: lesson 1 –
household electricity
Will use again in: lesson 3 –
fuses and circuit breakers
PLTS: Team workers – Work collaboratively with others.
Used before in: lesson 1 –
household electricity
Will use again in: lesson 3 –
fuses and circuit breakers
Keywords:
Fuse, RCCB, Earth, double insulation, diameter, electromagnet, current, resistance
Question: Why don't birds get electrocuted on power lines?
Answer: http://www.youtube.com/watch?v=rN3QhtnlCSw
Outcomes
• All students should be able to recall how a
fuse works and that there are different
types of fuse and state that circuit
breakers are safer than fuses.
• Most students should be able to describe
how a fuse works and they are different to
circuit breakers.
• Some students should be able to explain
how circuit breakers work and why they
are safer than fuses.
• Fuses and Circuit Breakers
Fuses Investigation
•
Results
Wire
Diameter
(mm)
Current when
RED HOT (A)
Current just
before MELTS (A)
0.355
0.315
0.274
0.234
0.193
0.152
•
•
Analysis
Plot a graph of each
Current (in Amps) on the
y-axis and Diameter on
the x-axis (in mm). You
will have two lines on one
graph – label them.
Conclusion and Evaluation
• Conclusion:
• Which would be the best piece of wire to
be a 3A fuse? Explain your answer.
• Write an evaluation explaining (a) if this
was the best way to carry out the
experiment. (b) Were there any things you
would change if you were to do this again?
(c) Explain any further tests you would
carry out to back up your conclusion.
Tell me two things...
(for each)
• that you have done well this session
• that you know now that you didn’t
know at the start
• that you could do better next time
• that you would like to know more
about