Electrical level 3 Module 7

Which force allows the transfer of power from one circuit to another or creates a new service

Mutal induction

What are the three parts of a basic transformer

Two coils and a single magnetic core

Why are transformers grounded

To stabilize voltage, remove static electricity, ground case in case of contact

Transformers are rated in

Kilovaltampres (KVA)

Name the advantages and disadvantages of auto transformers

Lower purchase price, better voltage regulation, lower sound levels and smaller size

To ensure maximum safety in a control transformer the secondary control circuit is

Isolated from the primary line circuit

In a step down transformer with a turn ratio of 8:1 what will be the voltage on the secondary if the primary voltage is 4160

520v

Which type of transformers can be ventilated , air cooled, or sealed

Dry-type

When a field from one coil cuts through the turns or a second coil, what actions occur

Induction

What is the voltage of the secondary in a transformer with 200 turns in the primary , 20 turns in the secondary and an input of 4400v

440

Three types of transformer core construction are

Butt,wound, and mitered cores

The installation of resistors and reactors are covered in nec article

470

What is the reactance

Opposition to AC due to capacitance and /or inductance

In a step down transformer what happens to the current in the same circuit

It is stepped up

Which forces are always present in an AC circuit

Inductance and true power

Which test instrument is used to verify the turns in a coil

Transformer turn ratio tester (TTR)

Most control transformers are

Dry type , step down

The power factor of a circuit can be improved by increasing the what of the circuit

Capacitor

Conductors connected to the high leg of a four- wires delta system be color coded with what color of insulation or tape

Orange

The what winding of a transformer is connected to the load

Secondary

The instillation and application of capacitors are covered in article

460

Magnetic leakage in a transformer causes a decrease in what when the transformer is loaded

Secondary voltage

What components are installed to increase the power factor and decrease the cost of electricity caused by large inductive loads

Capacitors

The insulating oil I'm a liquid filled transformer should be regularly test for

Dielectric strength