Electrical Flashcards
An electromagnet loses its magnetism when it is de energized
True
Higher currents in a conductor cause weaker magnetic fields around the conductor
False
An open circuit does not allow the current to return to the source
In a three phase generator the windings of the output are seperated by 120 mechanical degrees
True
Which unit is used to measure current flowing in a circuit
Amperes
Which of the following offers the greatest resistance to flow of electricity?
And insulator
What determines how severe an electric show will be?
Duration, time, and path of current
What current can be forced through a resistance of 10 ohms by a pressure of 110 volts?
11 amps
Which formula is used to find the electro motive force?
E= I x R
A solenoid is?
A magnetically controlled valve
Each person working on electrical equipment must ______ before proceeding with the work
Lockout, tagout
Why are tags used in addition to locks when locking out electrical equipment?
They provide additional information as to why the equipment is out and who is working on the equipment
Name 4 good conductors in the order of lowest resistance to current flow:
Silver, copper, gold, aluminum
Three good insulators
Plastic, glass, mica
To reverse the direction of a three phase motor…
Switch any 2 leads
Ohms law has 3 interdependent quantities that govern the flow of direct current, they are?
Voltage, current flow, and resistance
Why does inserting a soft iron core into a solenoid winding greatly strengthen the power of the magnet?
Soft iron induces the EMF
What does alternating current mean?
Current changes flow from negative to positive 60 times per second
Voltage can be compared to _____ in a hydraulic circuit
Pressure
Ampered can be compared to _____ in a hydraulic circuit
Flow
Resistance is measured in?
Ohms
Which is the correct formula for Ohms?
I = E/R
What common materials are used as conductors?
Silver, copper, aluminum
The power dissipated by a resistor that has 5 amps flowing through it with 120 volts applied is ______ watts?
600
What will be the current through a 10 ohm resistor when it is connected across 100 volts
10 amps
How many keys can be used for each lock when locking out equipment?
One
Magnetic lines of force:
Never cross
What is the electrical charge of a proton?
Positive
The resistance of components can be tested using an:
Ohmmeter
What are the characteristics of magnetic poles?
Un similar poles will attract each other
2 sources of Direct Current
Welder, Generator, Battery
2 sources of Alternating Current
Alternator, invertor, power plant
