Three-Phase Motors And Starters

Question 1

What is the most common starting method?

Answer 1

Across the line voltage start

Question 2

Terminals on a part winding motor

Answer 2

T1 T2 T3 T7 T8 T9

Question 3

Terminals on a Wye Delta motor

Answer 3

T1 T2 T3 T4 T5 T6

Question 4

What is the purpose of a reduced voltage starter

Answer 4

Reduce inrush current

Question 5

List two starting modes common on electronic soft starters

Answer 5

Ramp starting

Current limiting

Question 6

List five advantages of using a 15 hp three-phase motor over single phase motor of the same rating

Answer 6

Lower cost for the motor 
more readily available 
more efficient 
smaller for the same horsepower 
quieter running

Question 7

If a rotary phase converter is rated for a maximum of 10 hp for starting and 30 hp for running it can supply motors whose hp ratings add up to ___ hp but with the largest motor not greater than ___ hp

Answer 7

If a rotary phase converter is rated for a maximum of 10 hp for starting and 30 hp for running it can supply motors whose hp ratings add up to 30 hp but with the largest motor not greater than 10 hp

Question 8

The load to a rotary phase converter must not be connected until the converter reaches it’s rated speed and is supplying three-phase power.

True or false

Answer 8

True

Question 9

Rotary phase converters can supply more than one load.

True or False?

Answer 9

True

Question 10

A static phase converter can supply power to a single three phase motor.

True or False

Answer 10

True