71
rated interrupting capacity, also called breaking capacity, which is the
maximum current the fuse can safely interrupt.
Compose questions to the description of fuses. Practice asking and
answering questions about fuses
TEXT C. RELAY
Look at the text below. Guess what the text is going to be about.
What kind of text is it? Where can it be published?
Read the article and highlight the main idea
What is a Relay and How it Works?
July 3, 2020 by Madhu
Relays
are electrically operated devices that can open or close the
contacts electrically. It can be used to turn ON or OFF (make or break) the
circuits or where several circuits 1. _________or high-power circuits that can
be controlled by low power signals.
A protective relay is a device that 2. ________and initiates the operation
of the circuit breaker to isolate the faulty element from the rest of the healthy
power system.
The relay construction comprises of various mechanical parts that are
located inside the outer casing. The mechanical parts of the relay 3. _________.
The relay has two circuits namely control
circuit
and load circuit which are
physically isolated. The control circuit has an
fixed switch
contacts, and the load circuit has movable switch contacts, movable armature,
spring and the load (bulb) to be actuated. The most important part of the relay is
the electromagnet. It is a soft iron core wounded by a coil. It can acquire the
properties of a magnet when a voltage 4. ________ . Because when a voltage is
applied to a metal winded with copper wire, it can act as a magnet. The
movable armature can make or break the contacts. The spring can keep the
contacts separated until the electromagnet is energized.
The relay operating principle is, when a
is applied to the
electromagnetic coil, it magnetizes the iron core and 5. ________which attracts
the armature towards it. This makes the contact to close (closing the load
circuit) or open in case if it is normally closed relay (depends upon the
construction).
When the voltage is removed, the spring 6. _____, which breaks the load
circuit.
