TRANSFORMERS

Laminated insulation are normally used in the transformer:

• To reduce the hysteresis effect

• To increase the hysteresis effect

• To reduce the effect of eddy current

• To increase the effect of eddy current

A transformer has:

• primary and secondary windings, both of which are considered inputs

• a primary winding used as an output and a secondary winding used as an input

• primary and secondary windings, both of which are considered outputs

• a primary winding used as an input and a secondary winding used as an output

A Transformer______________

• Changes dc to AC

• Steps up or down AC Voltages & Current

• Changes ac to DC

• Steps up or down DC Voltages & Current

Tags

NGSS.HS-PS3-3

Increasing the number of turns of wire on the secondary of a transformer will:

• decrease the secondary current

• increase the primary current

• increase the secondary current

• have no effect on the secondary current

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

If the primary power of an ideal transformer having a 2:1 voltage ratio is 100 W, the secondary power is:

• 200 W

• 75 W

• 50 W

• 100 W

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-3

If dc voltage is applied to the primary of a transformer it may:

• Work

• Burn the winding

• Give lower voltage on the secondary side

• Give higher voltage on the secondary side

The primary and secondary induced emfs in two winding transformer are always:

• Antiphase with each other

• In phase with each other

• Equal in magnitude

• Determined by load on transformer secondary

A transformer does not change the following:

• Frequency

• Voltage

• Current

• None of these

Transformer ratings are usually expressed in terms of :

• Voltage

• KVA

• kWh

• KW

The noise in transformer core due to the vibrations of laminations is called:

• Flicker noise

• Transit time noise

• Agitation noise

• Humming noise