Transformers Week 2 Questions Flashcards
A name plate reads- 7200/12470Y how do I connect this to a 7200/12470 system?
WYE- Phase to Ground
A name plate reads- 7200/12470Y how do I connect this to a 4160/7200 system?
Delta- Phase to Phase
If a name plate lists 2 primary numbers separated by a / which is the primary coil rating?
The smaller of the 2 numbers
A nameplate reads 12470GRDY/7200. How many primary bushings does this transformer have?
One, H1. the H2 is the tank ground and it’s a WYE only connection
Engineers can choose from 3 different primary voltage designations when buying transformers, what are they?
WYE Only, WYE and DELTA, DELTA only
If a transformer nameplate has only one number listed for a primary voltage rating, how should it be connected?
DELTA = Phase to Phase
What information would you typically reference the nameplate for?
Voltage Ratings, KVA, Serial Number, Polarity, Impedance, Weight
Why is it important to perform a continuity test on a transformer before installation?
To test for a faulty transformer
What must be done before connecting the customers load?
Check Secondary Voltage at meter socket
When you perform a continuity test on a transformer and you hear a beep when reading between H1 and X1, what does that mean?
It’s a Faulty Transformer, connection between high and low side means bad transformer
A nameplate reads 12470GRDY/7200 volts. How would it connect to a 4160/7200-volt system?
Can Not connect, can only connect transformer to WYE system
What is a tap changer used for on a transformer?
To Change the secondary voltage output by changing the windings on the primary coil. Do not operate energized, Raises or lowers secondary voltage by 2.5% or 4.5%
What is polarity?
The direction of power flow, Subtractive and Additive
What is impedance?
Total Opposition to current Flow, Efficiency of the transformer
What is a dual voltage switch and when can I operate it?
The transformer has two primary coil voltages example (7200/14400) do not operate energized (dual rated)
