Fault finding and rectification - advanced, test instrument settings, readings, test procedures, typical faults, supply faults, fault-finding procedures - 8 questions from a bank of questions
During fault finding on a problematic mains AC supply, the following waveform is displayed on an oscilloscope. What is being displayed here?
a sinewave with noise
a sinewave with transients
a sinewave with voltage 'spike'
a 'clean' supply
During fault finding on a problematic mains AC supply, the following waveform is displayed on an oscilloscope. What is being displayed here?
a sinewave with noise
a sinewave with transients
a sinewave with voltage 'spike'
a 'clean' supply
During fault finding on a problematic mains AC supply, the following waveform is displayed on an oscilloscope. What is being displayed here?
a sinewave with noise
a sinewave with varying frequency
a sinewave with a transient voltage 'spike'
a 'clean' supply
Computers and computer networks can sometimes 'lock-up, freeze or reset' if there is mains distortion or interference on the mains supply. What is the term used to describe this?
blackout
noise
brown-out
wipeout
Which one of the following installations is likely to present a 'laser' hazard during fault-finding operations?
computer network in a large commercial office
motor speed-controllers in a manufacturing facility
standby mains supplies at a hospital
power-factor correction equipment in a large factory
Which TWO of the following installations is likely to present an 'electric shock risk' after the mains has been isolated, during fault-finding operations? (TICK ANY TWO ANSWERS BELOW THEN CLICK 'CHECK'. IF YOU HAVE BOTH CORRECT ANSWERS SELECTED CORRECTLY - the message will say 'correct - well done')
A poorly terminated conductor in a lighting circuit, carrying current, is likely to lead to......?
excess heat at the terminal
allow better current flow to the lamp
cause the lamp to become dim
trip a circuit breaker
Contactors inside electrical equipment can sometimes 'burn-out'. Which ONE of the following types of equipment would normally contain 'contactors'?
motor control panels
light switch
domestic fridge
standard A1 ring
Which ONE of the following is a common cause of 'lamp failure' in a domestic dwelling?
high ambient temperatures
expiry of lamp life
faults in the lighting circuit
incorrect voltage applied
Which ONE of the following information is of very little use when investigation a fault?
type of supply at the premises
type of earthing arrangement at the premises
type of protective devices installed at the premises
type of cable system installed
During fault finding, how can the current drawn by a very large three-phase motor be determined with the least amount of inconvenience?
use of a clamp meter on each phase
fit an ammeter in parallel with the supply phases
fit an ammeter in series with the supply phases
use the information on the motor ID plate to calculate the current
Which ONE of the following installations is not likely to represent an explosion risk due to static discharge, during fault finding operations?
flour mill
petrol station
paint shop (car spraying)
food stores
What is the instrument range for fault-finding a potential Insulation failure in a large motor?
m OHM
M OHM
micro OHM
OHM
What is the instrument range for fault-finding a potential conductor continuity failure in a large motor?
k OHMs
M OHMs
micro OHMs
LOW OHMs
What is meant by the term 'downtime' when faultfinding on a piece of equipment in a high volume manufacturing facility?
the time spent not working on the fault
lunch and breaktimes
the duration of time when the equipment is not working
the time spent looking for the fault prior to fixing it
If you had to fault-find and repair a piece of electrical equipment that was missing some detail of its 'nomenclature' (the nameplate that contains the voltage, power, p.f., duty cycle etc). How could/should this missing information be acquired to enable safe and effective repair?
find a similar looking piece of equipment and read the values off its nameplate