WORKSHOP MANUAL
ZT 5132 T
Chapter
7 - ELECTRICAL SYSTEM
EDITION
2017
PAGE
47 /
57
7.2.4 Ignition switch
NOTE
-
Refer to the wiring diagram of the machine (continuity diagram) to determine switch func-
tions and test using the methods described.
The ignition switch incorporates a number of functions, although not all functions are used on all
machines. It is a three-position switch: OFF, RUN, START with momentary contact.
Use an ohmmeter to check for continuity in each position.
• «OFF» Position -
There must be continuity between contacts G, L and M. These connections
ground the engine magnet and stop the engine in the OFF position.
• «RUN» Position -
There must be continuity between contacts B and L. These connections pro-
vide power to the rest of the wiring. Connections G and M open reciprocally.
• «START» Position -
Hold the switch in the START position while testing. There must be conti-
nuity between contacts B, L and S. These connections apply power to close the solenoid con-
tacts and engage the starter motor.
In addition to the tests above, set the switch to the «RUN» position and check between each con-
tact and the ground (metal part) to ensure that no terminals are grounded. If the switch is function-
ing properly, there will be no continuity between the contacts other than that described.
7.2.5 Relays and Solenoids
Solenoid and relays are both magnetically operated devices. Both devices operate on the principle
that passing a current of electricity through a coil of wire will create a magnetic field strong enough
to attract a piece of iron or steel. Each device uses this principle in a slightly different manner.
•
Relay
- A basic relay consists of a coil of wire wound around a soft iron (magnetic) core. When
current is passed through the coil, the core is magnetized and pulls down on a magnetic lever.
The lever in turn is attached to several switch contacts which open or close other electrical
circuits. In this fashion, a small current can control one or more larger electrical currents and
actuate several other devices. In most cases a relay contact moves only a fraction of an inch
and the magnetic pull is low.
• Solenoids
- A basic solenoid consists of a coil of wire wound around a hollow tube. A magnetic
core slides inside the tube. When current is passed through the coil, the core is pulled into the
solenoid with considerable force. With proper design, a solenoid can exert considerable force
over a distance of several inches. A solenoid can therefore, pull a lever, close a heavy contact,
or perform other jobs that require a straight line pull.
