Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
|
What is true of analog meters |
An analog meter uses current from the circuit under test to read voltage |
|
|
What is true when placing an ammeter into a circuit |
The meter is placed in series with any component |
|
|
The ohms per volt specification of an analog meter is best described as |
The resistance the meter introduces to the circuit |
|
|
An ammeter should be set to what scale in order to read a current of 2,000 ma. |
10 amp |
|
|
The ac voltage as read on a digital voltmeter is always indicated as |
RMS |
|
|
How is the ohmmeter scale of an analog meter best described |
A non-linear scale from infinity to zero |
|
|
What procedure could be used to test the current drawn by a DC hoist machine brake coil |
Measure the voltage across a precision shunt placed in series with it |
|
|
What is the result of connecting an ammeter to the terminals of a power supply or other voltage source |
The meter will be damaged |
|
What will be the phase relationship between the primary and secondary voltages |
The secondary voltage will be 180° out of phase |
|
What does this symbol represent? |
Iron core transformer |
|
|
What statement best describes Eddy currents |
They are circulating currents set up by magnetic induction |
|
|
How are the primary and secondary windings of a transformer identified as |
Primary H, secondary X |
|
|
What would you do to check for an open primary winding |
Measure the resistance across the primary |
|
|
What will the secondary resistance be when the secondary winding is open |
Secondary resistance will be infinity |
|
|
What is true when a secondary winding is completely shorted |
Current through the primary is high |
|
|
The speed of the rotating magnetic field in an AC induction motor, determined by the frequency of the AC power line and the number of poles in the motor |
Synchronous speed |
|
|
What uses a stator to act as a rotating field |
AC induction motors |
|
|
Which motor can be run on AC and DC |
Universal motor |
|
|
What is the rotating speed of a 3 phase 30 HZ six pole motor |
600 RPM |
|
|
What describes the inherent opposition to change in current with an electromagnetic device |
Inductance |
|
|
How must a nine lead, three-phase motor be wired for low voltage setting |
L1 (1,7) L2 (2,8) L3 (3,9) (4,5,6) |
|
|
What does a square with a darkened upper triangle represent |
DC relay |
|
|
The door close limit switch is not working, you have power from terminal 55 to terminal 8, no power from terminal 1 to 32, why? |
Door limit switch malfunction |
|
|
What is correct regarding transformers |
Applied voltage on the primary, leads current by 90° |
|
|
Which statement applies when the secondary winding is partially shorted |
Current through the secondary is low |
|
|
If a current carrying wire is placed perpendicular to a field created by two magnets of opposite polarity what happens |
The conductor is moved at right angles to the flux from the magnetic poles |
|
|
What does the right hand rule for motors determine |
Direction of the current carrying conductor movement in a magnetic field |
|
|
What describes a pole pieces inability to proportionally change its magnetic flux as changes in voltage occur |
Hysteresis losses |
|
|
What is used to lubricate a sleeve bearing |
Oil |
|
|
How is a magnetic field produced in a field coil |
Current must pass through it |
|
|
In a DC series generator, current flows only when? |
Current flows only when there's a load |
|
|
What is used to control Exciter output voltage level |
The strength of the shunt field |
|
|
What is correct about a shunt generator |
It's output drops as load is increased |
|
|
What is the generator series field connected in parallel with |
Series field shunt |
|
|
What is correct for the cumulatively-compounded generator |
The series field aids the shunt field |
|
|
What is the series field connected in series with |
The armature |
|
|
What is correct about an Exciter field circuit |
It's self-exited |
|
|
Which is a method used as a final acceleration step for hoist motor |
Weakening the shunt field |
|
|
In damping motor control what is the rate of acceleration of the hoist motor dependent on |
The rate CEMF builds up in the damping motor |
|
|
A motor needs a sleeve bearing replaced. What type of bearing will you need? |
Friction bearing |
|
|
A shunt generators output drops when? |
When load is increased |
|
|
In cumulatively compounded generators, the series field does what |
Series field aids the shunt field |
|
|
The strength of the shunt field is used to ?? |
..to control Exciter output voltage level |
|
|
The creation of an EMF in a conductor through relative motion between the conductor and a magnetic field |
Induction |
|
Directions of left hand rule |
Thumb=motion of conductor Pointer=direction of flux Middle=direction of Emf |
