Horn Circuit - Kubota u15-3 Workshop Manual

WSM U15-3
r. Horn circuit
1. Structure
(1) Diaphram (5) Stop screw
(2) Point (6) Stay
(3) Horn coil (7) Air gap
(4) Nut
The horn consists of acoustic diaphragm, point, horn coil and other parts. It comes in spiral, flat and
other types in construction.
Currently, the flat type is most widely used. A typical flat horn is shown at right.
(3)
(1)
(2)
2. Function
Shown above is the horn drive circuit. When the horn switch is pressed, current flows to the horn relay to
get its contact P1 closed. The current from the battery now flows directly through the horn coil and the
contact P2, which magnetizes the core and attracts the moving plate. Then the contact P2 opens itself
and the current is interrupted. The magnetic force then disappears and the spring-loaded diaphragm
comes back to the original position. The contact P2 closes itself, and the current flows again through the
coil to attract the moving plate. The above series of actions are repeated to keep the diaphragm vibrat-
ing, producing sound.
(8)
(9)
(6)
(5)
(7)
(4)
II-164
(1)
(2)
(3)
(4)
(5)
(1) Battery
(2) Horn switch
(3) Horn relay
(4) Diaphram
(5) Core
(6) Coil
(7) Moving bolt
(8) Adjust nut
(9) Moving plate
(6)
(7)