C Flashcards
Delta low voltage connection is connected in?
Parallel.
3 groups of 3 leads
9 leads at JB. T1-T9
3 leads are internal
What voltage is for low voltage and what voltage is for high voltage
Low = 230v
High - 460v
Wye low voltage is connected in?
Parallel
3 groups of 2 leads
1 group of 3 leads
Both delta and wye high voltage are connected in?
Series
Motor starters can be either?
Across the line starters or
Reduce full voltage starters
Full voltage starters typically produce a starting current that is?
500% - 600% of full load current and
Starting torque that is 150% of full load torque
Across the line starters can be?
Manual or magnetic starter design
Manual motor starters use a?
Manual open close switch
Magnetic starter uses?
Electrically operated switch
What are these symbols?
TDOE - time delay on energization
What are these symbols
TDOD
Timed delay on de energization
What kind of taps can an auto transformer have?
80, 65, or 50% taps
The starting currents % to the starter are?
64, 42 and 25% of full voltage starting current
Auto transformer starters can be?
Open or closed transition starters
Wye delta starting requires a Delta motor that has ____ terminal leads?
- T1- t6
Connected in wye for starting and reconnected in delta for running
When a motor is connected in wye to start, the in rush current and torque can be reduced to?
33 1/3%
For an open transition wye delta start the overload settings are based on?
57.7% of full load current
Which starter can be used as a disconnecting means by the CEC?
Manual
A six lead motor has T1 T2 T3 T7 T8 and T9. what type of motor is it?
Wye
How many conductors must be run between a part winding motor and starter?
6
The line starting current of an auto transformer starter is?
Less than the motor starting current
What is the main intent of using reduced voltage starters
Reduces in rush starting current
What is meant by current limit starting when provided by a soft starter?
Current limit starting restricts the starting current to a max value
What’s the best choice of starter if you required the gradual acceleration of a constant torque load?
Soft starter
Is 3 phase power always available?
No
Phase converters have several applications in industries that have a single phase service including?
Farms
Small industrial plants
Woodworking shops
Metal fabrication shops
Which motor is more complicated?
Single phase motors
Single phase motor attributes are?
Have more parts
Are noisier
Are larger
Require more maintenance
3 phase motor attributes are?
Less expensive
More readibly available
Smaller
Quieter
What is a phase converter?
Controllers that allow one or more 3 phase motors to run on Single phase system
What are 2 types of phase converters?
Rotary and static phase converter
Which phase converter produces better output?
Rotary because it uses the a motor generator
What is the main component of a rotary phase converter?
Induction motor generator
What are two power ratings of a rotary phase converter?
Max hp run, max hp start
If more than one phase converter motor is started which one should be stated first?
The largest
What type of capacitor does a phase converter need for starting?
Electrolytic
What type of capacitor does a phase converter need for running?
Film or pull filled
What does an auto transformer do?
Adjusts the voltages to the 3rd line using taps?
Which line of a phase converter has consists current regardless of the load?
L3
Part winding starter has ___ leads?
Six
Soft starters have two acceleration modes. What are they?
Ramp starting
Current limit starting
Single phase motors are not available above ___ hp?
15
Single phase motors are not common above ___ hp?
5
A _____motor starter is the best choice for motor control?
Magnetic
A small machine shop installed a 3 phase exhaust fan. What type of phase converter should be used?
Static
On a farm or wood shop what is the best phase converter to use?
Rotary
