HOW TO DIAGNOSE
8-31
16A0253
:
1,
1
1
2 3’
~
,4
5 6
~
,,
,,
16W898
Coil .
Iron
piece,
Cover
Spring
Iron
core
Contact
1680231
Power supply
I I
Relay
Fuse
t
1
Light
=
=
16A0254
Normal open (NO) type
3.
The relays may be classified into the normal open type and
Deenergized state
Energized state
the normal close type by their contact construction.
I
NOTE
2. SWITCH CONNECTION
This figure illustrates a complex switch. The continuity
between terminals at each position is as indicated in the
table below.
1 st stage
NOTE
O-O denotes continuity between terminals.
CHECKING RELAYS
1.
When current flows through the coil of a relay, its core is
magnetized to attract the iron piece, closing (ON) the
contact at the tip of the iron piece. When the coil current is
turned off, the iron piece is made to return to its original
position by a spring, opening the contact (OFF).
2.
By using a relay, a heavy current can be turned on and off by
a switch of small capacity. For example, in the circuit shown
here, when the switch is turned on (closed), current flows
to the coil of the relay. Then, its contact is turned on
(closed) and the light comes on. The current flowing at this
time to the switch is the relay coil current only and is very
small.
The deenergized state means that no current is flowing
through the coil and the energized state means that current
is flowing through the coil.
Current does not flow
Current flows
16A0256