Relays - Kubota u15-3 Workshop Manual

t. Relay
1. Relays location
(A) Starter lock relay
(B) Auto release relay
(C) Auto release stabilizer relay
(D) ESS relay
(E) Lever lock relay
(F) Cab relay
(G) First self hold relay
(H) Reverse relay
2. Purpose of relays
Electrical devices on the load side - heater, glow plug,
cab instruments, for example - tend to require large
current. This means that the wire harnesses running
the power source up to the switches and loads must involve thick, large-capacity cables. This is disad-
vantageous in costs, weight and safety. What's worse, turning on and off a large-current circuit with a
manual switch may cause a spark and get the switch in trouble.
Here come the relays in the switching circuits. The relays can be on/off-controlled using fine, small-cur-
rent cables, and the switches can last longer. These switches may also be conveniently located.
A large-capacity harness may be connected from the power source via the relay to the load. In this
design, the harness is made shorter, less expensive, and safer.
1) Switch OFF
Normal open relay (a-type)
Contacts marked with white dots
No current flowing
Current flowing
(I) Second self hold relay
(J) Self hold release relay
(K) Travel high relay
(L) Horn relay
(M) Auto release controller
(N) Auto glow controller
(D)·(E) Anti theft version only
Relay
Load
Type of relay
Normal close relay (b-type)
Contacts marked with black dots
No current flowing
(M)
2) Switch ON
sw
Current flowing
II-171
WSM U15-3
(N) (G) (H) (I) (J) (K) (L)
(A) (B) (C) (D) (E)
Relay
Load
Combined relay
Current flowing
No current flowing
No current flowing
Current flow
(F)
sw