Lesson 7 - Electricity SAQ
This lesson allows you to test yourself on the material covered in the Electricity lesson and determine the level to which you have met the learning outcomes.
Suggested Response - Q1
* Are the following statements true or false? Provide reasoning for your answer.
a) Current and power are the same thing.
b) Direct current has a lower frequency than alternating current.
c) A big brewery only needs three-phase power.
d) A transformer allows you to convert power from one voltage to another.
e) Two-pole motors rotate faster than four-pole motors.
f) Power factor correction is used to decrease maximum demand.
Response:
a) False. Current is the amount of electrical charge that is transferred, and it is measured in amperes (A). Power is the rate at which electrical work is performed, and it is measured in watts (W).
b) False. Direct current does not have a frequency, as the frequency refers to the number of times the current and voltage change direction and this is measured in hertz (Hz).
c) False. A big brewery will need three-phase power for the bigger equipment, but it will still need single-phase power for applications such as lights and office equipment. Direct current for certain instruments may also be required.
d) True.
e) True.
f) False. Power factor correction optimises the use of power supplied so that we get maximum value from it. Maximum demand refers to the peak loads on a system.