week 2 (chapters 4-5) Flashcards
provides information on how to store, transport, install, maintain, and inventory the unit?
nameplate
lineman use the nameplate to ensure?
primary voltage is chosen
secondary is chosen
impedence is within +/- 10%
weight
where is the nameplate typically found?
overhead: on or near lower mounting bracket
underground: inside door on the face
a nameplate with a primary coil voltage printed last and H1A H1B bushings in the schematic is what type of transformer?
underground
the primary coil voltage is always ________ of the two voltages?
smaller
most useful information on the nameplate?
voltage ratings
KVA
serial
polarity
impedance
schematic
always check the _________ to determine proper ________ before installing
nameplate/voltages
always verify the __________ _______ with an approved voltmeter before connecting the customer’s load.
secondary voltage
transformer manufactures comply with _____ standard C57.12.00 when designating winding voltage ratings?
ANSI
what are the three ways transformers can be purchased according to their primary voltage designations?
phase to phase only
phase to ground only
phase to phase / phase to ground
a nameplate with only one number listed for the primary voltage is a ______ connection.
Delta
phase to phase is synonymous with what connection type?
Delta
when using a transformer for both delta and wye connections, no matter what connection type is used, the primary voltage is still going to be?
the smaller of the two voltages
when ever you see GRDY on a nameplate, it is automatically a _____ connection
Wye
duel rated transformers have what function?
two primary coil ratings
an external no-load switch is found on a ___________ transformer?
dual-rated
the duel voltage switch must only be operated when?
when the transformer is de-energized
tap changing transformers only effect the voltages to the?
customers
provides the same secondary voltage at different points on the system where primary voltage may not be the same?
tap changers
depending on the manufacturer, each tap raises or lowers the secondary voltage by ?
2.5 or 4.5 %
is the tap changer connected to the primary or secondary coil?
primary
an audible sound should not be heard between the ______ and _______ windings when conducting a continuity test.
primary/secondary
what is used to test insulation of a transformer?
megger
what test is done with the low input voltage connected to the high voltage winding?
turns ration testing
a transformer with only one primary bushing would be a ______ connection?
Wye
H1 to phase/H2 to phase is a _______ connection?
Delta
a nameplate has 7200/12470Y for primary voltages and the system voltage is 4160/7200. is this a delta or wye connection?
Delta (small to large primary)
a transformer has “7200” as the primary winding rating. is it delta or wye connection?
Delta (phase to phase)
