EMC Chapter 11 Flashcards
Transformers are used to increase generated ___ to a high level for transmutation across the country and then decrease it to a low level for use by electrical loads.
voltage
The ___ winding is the coil of a transformer that draws power from the source.
primary
If the turns ratio is 2:1, the transformer is a ___ transformer.
step-down
Because iron is a fair conductor of electricity, the varying magnetic field that induces a voltage in the secondary of a transformer also induces small voltages in the iron core of the transformer. These small voltages product ___.
eddy currents
___-phase connections are found in commercial and industrial applications.
Three
Low voltage transformer windings are marked with an ___.
X
A service ___ is an electrical service in which service-entrance conductors are run underground from the utility system to the service point.
lateral
A ___ is a connection brought out of a winding at a point between its endpoints to allow the voltage or current ration to be changed.
tap
___ VAC power is used to supply devices in a residence that require a large amount of operating power, such as a central air conditioner, water heater, clothes dryer, and cooking range.
240
To obtain a control voltage of 120 VAC from a line voltage of 480 VAC, the two primary coils must be connected in ___.
series
A transformer that is selected for an application must have a higher ___ rating than necessary for the application.
volt/amperage
The most important guideline when sizing a transformer is to select a transformer that safely and efficiently provides the maximum ___ that can be drawn by a load.
current
When selecting a transformer, it a machine does not have devices with high inrush characteristics, inrush current is not as much of a consideration. In this case, the ___ current is more important.
steady-state
One method that can be used to determine whether a transformer has failed is to measure the input and output ___.
voltages
A DMM set to measure ___ can be used to check for open circuits in the coils, short circuits between the primary and secondary coils, or coils shorted to the core without power applied to the transformer.
resistance
