Transformer Theory
Transformer Formula
Electrical Code
OVERCURRENT PROTECTION
Random
100
The amperage of a single phase transformer is found by dividing the KVA rating of transformer by the primary or what voltage
What is secondary voltage
100
No matter the formula regarding transformers, this value always remains the same.
What is POWER? (kVA, kW)
100
WHAT TABLE IN THE 2014 ELECTRICAL CODE BOOK IS USED FOR TRANSFORMER OCPD OVER 1000 VOLTS
What is TABLE 450.3 (A)
100
This is the NEC Article that covers "Over-current Protection"
What is Article 240
100
This is the ONLY thing you should quote over the phone without seeing a job.
What is "hourly rate plus material"?
200
The windings of a open-delta connected system only pull what percentage of the line current
What is 57-58%
200
WHAT IS THE SQUARE ROOT OF 3
What is 1.732
200
WHAT NEC ARTICLE IS USED TO KNOW THE NEXT SIZE OCPD?
What is SECTION 240.6 (A)
200
This type of fuse is used when a high in-rush current is expected at start-up.
What is a "dual-element time-delay fuse?
200
This is an estimator's most useful resource?
What is "HISTORICAL DATA"?
300
How many volts across phase to phase in a 277/480 VOLT system
What is 480 volts
300
What IS 480 DIVIDED BY 277
What is 1.732
300
what NEC article COVERS MOTORS
What is Article 430
300
AT CURRENTS GREATER THAN 9 AMPS,THE PRIMARY OCPD FOR A 30 KVA TRANSFORMER 480 VOLTS 3 PHASE?
What is A 50 AMP OCPD
300
The transfer of electrical energy from one circuit to another without the aid of electric connections is known as?
What is Mutual Induction?
400
This transformer configuration produces these secondary voltages phase to ground, 120, 120, 208.
What is a "Delta".
400
what is the ratio of a 7200 to 240/120 VOLTS
What is 30:1?
400
This NEC Article covers work space about equipment.
What is Article 110
400
IS THE MAXIMUM NUMBER OF SERVICE DISCONNECTS GROUPED TOGETHER WITHOUT REQUIRING A "MAIN" DISCONNECT
What is 6?
400
For all practical purposes, there are ____ number of categories of electrical hazard?
What is "4"? (CAT I, CAT II, CAT III, CAT IV)
500
If the transformer voltage is increased the current will do this.
What is DECREASE
500
Assuming a pf of 1.0, a 10kVA transformer will service a load of _____amps @ 240V
What is 42 Amps?
500
this NEC Article covers "Capacitors"
What is NEC Article 460?
500
TRANSFORMERS RATED OVER WHAT VOLTAGE SHALL BE INSTALLED IN A VAULT?
What is 35,000VOLTS? (35 kV)
500
A transformer's apparent power is rated in kVA while it's TRUE power is rated in kW determined by ______.
What is pf or power factor?
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