問題一覧
1
A __ is an electric device that uses electromagnetism to change voltage from one level to another or to isolate one voltage from another
Transformer
2
The strength of the __ and the current are directly related
Electromagnetic field
3
A strong concentrated electromagnetic field is developed when a conductor is wrapped into a __
Coil
4
If a transformer name plate indicates that leads H1 and X1 are adjacent to each other and wound in the same direction with respect to the core the polarity is __
Subtractive
5
__ Sequence harmonics have the opposite phase sequence to the fundamental harmonics
Negative
6
__ is the order in which waveforms from each phase (A, B, and C) cross zero
Phase rotation
7
Which of the following magnetic quantities is analogous to the electrical equivalent of voltage?
Magnetomotive force
8
Electrical power circuits must be insulated by __ where they enter the transformer tank
Bushings
9
Which answer does not strengthen the electromagnetic field of an electromagnet
Applying an AC rather than a DC voltage source
10
When a magnetic circuit reaches a point of saturation ___
Further increases I. flux density are not possible
11
A __ is a material that is easily magnetized
Ferromagnetic material
12
The method used to test for polarity and check transformer lead markings do not include
Polarization index test
13
A Transformer has a secondary voltage of 12V and a turns ratio of 10:1. What is the value of the primary voltage?
120V
14
The primary function of a 3 phase __ is to reduce the fifth and seventh harmonic currents generated by six pulse (six diode) converters that change AC to DC
Harmonic filter
15
In a balanced 3 phase, delta connected system, the line current is equal to __ times the current in one of the coils
1.73*
16
__ is a force that acts at a distance and is caused by a magnetic field
Magnetism
17
An __ uses capacitors and inductors that are turned to remove particular harmonic frequencies
Passive harmonic filter
18
Wye to delta connected transformers, with properly marked leads, have an angular phase displacement of __ degrees
30*
19
What is the turns ratio of an ideal 15 kVA single phase transformer with a 480V primary and a secondary full load current of. 62.5 A
2:1*
20
Identify the transformer connection below
Pri, wye low/ sec. wye low volt
21
A transformer has a secondary voltage of 120V The primary winding has 1800 turns and the specials 90 turns. What is the value of primary voltage
2400 Volts
22
The turns ratio of a transformer which is rated for a primary voltage of 2400V and has a secondary rating of 120V is __
20:1
23
Identify the transformer connection below
Wye Wye/ Single voltage
24
Which transformer is connected for a primary: higher voltage WYE, secondary: lower voltage DELTA configuration
Transformer A
25
Which transformer is connected to a primary: lower voltage DELTA, secondary: higher voltage WYE configuration
Transformer D
3rd Year- Fire Alarm
3rd Year- Fire Alarm
ユーザ名非公開 · 50問 · 1年前3rd Year- Fire Alarm
3rd Year- Fire Alarm
50問 • 1年前ユーザ名非公開
3rd Year - Lighting Essentials
3rd Year - Lighting Essentials
ユーザ名非公開 · 30問 · 1年前3rd Year - Lighting Essentials
3rd Year - Lighting Essentials
30問 • 1年前ユーザ名非公開
3rd Year- Grounding and Bonding
3rd Year- Grounding and Bonding
ユーザ名非公開 · 40問 · 11ヶ月前3rd Year- Grounding and Bonding
3rd Year- Grounding and Bonding
40問 • 11ヶ月前ユーザ名非公開
問題一覧
1
A __ is an electric device that uses electromagnetism to change voltage from one level to another or to isolate one voltage from another
Transformer
2
The strength of the __ and the current are directly related
Electromagnetic field
3
A strong concentrated electromagnetic field is developed when a conductor is wrapped into a __
Coil
4
If a transformer name plate indicates that leads H1 and X1 are adjacent to each other and wound in the same direction with respect to the core the polarity is __
Subtractive
5
__ Sequence harmonics have the opposite phase sequence to the fundamental harmonics
Negative
6
__ is the order in which waveforms from each phase (A, B, and C) cross zero
Phase rotation
7
Which of the following magnetic quantities is analogous to the electrical equivalent of voltage?
Magnetomotive force
8
Electrical power circuits must be insulated by __ where they enter the transformer tank
Bushings
9
Which answer does not strengthen the electromagnetic field of an electromagnet
Applying an AC rather than a DC voltage source
10
When a magnetic circuit reaches a point of saturation ___
Further increases I. flux density are not possible
11
A __ is a material that is easily magnetized
Ferromagnetic material
12
The method used to test for polarity and check transformer lead markings do not include
Polarization index test
13
A Transformer has a secondary voltage of 12V and a turns ratio of 10:1. What is the value of the primary voltage?
120V
14
The primary function of a 3 phase __ is to reduce the fifth and seventh harmonic currents generated by six pulse (six diode) converters that change AC to DC
Harmonic filter
15
In a balanced 3 phase, delta connected system, the line current is equal to __ times the current in one of the coils
1.73*
16
__ is a force that acts at a distance and is caused by a magnetic field
Magnetism
17
An __ uses capacitors and inductors that are turned to remove particular harmonic frequencies
Passive harmonic filter
18
Wye to delta connected transformers, with properly marked leads, have an angular phase displacement of __ degrees
30*
19
What is the turns ratio of an ideal 15 kVA single phase transformer with a 480V primary and a secondary full load current of. 62.5 A
2:1*
20
Identify the transformer connection below
Pri, wye low/ sec. wye low volt
21
A transformer has a secondary voltage of 120V The primary winding has 1800 turns and the specials 90 turns. What is the value of primary voltage
2400 Volts
22
The turns ratio of a transformer which is rated for a primary voltage of 2400V and has a secondary rating of 120V is __
20:1
23
Identify the transformer connection below
Wye Wye/ Single voltage
24
Which transformer is connected for a primary: higher voltage WYE, secondary: lower voltage DELTA configuration
Transformer A
25
Which transformer is connected to a primary: lower voltage DELTA, secondary: higher voltage WYE configuration
Transformer D