Electrical System; Starter Auto Reduction Unit; General; Basic Circuit - Kubota D1503-M-DI Workshop Manual

03-M-DI Series, WSM

4. ELECTRICAL SYSTEM

[1] STARTER AUTO REDUCTION UNIT

(1) General

The starter auto reduction unit (7) is designed to start the machine equipped with engine more reliably. This unit
has the following function by integrating an alternator (1) that puts out rpm-proportional pulses.
1. Fail-Safe Functions
a) Preventing the starter pinion from getting in mesh while the engine is runnning.
With the engine running, pulses from the alternator terminal P are constantly detected. Even if key switch (2) is
wrongly operated or the wiring gets short-circuited, the starter (5) can stay off, the starter (5) and flywheel ring gear
are effectively protected.
b) Starter auto reduction at a start of the engine.
When the engine has got started and the alternator (1) has reached the specified rpm, the electical current to the
starter (5) is automatically cut off, even if the key switch (2) is at the START position.
c) Safety mechanism in case of engine stall.
If the engine stalls with the key switch (2) at AC or START position, the key must be set once to OFF position for added
safety. The starter (5) is thus kept from turning on unexpectedly.
2. Other Features and Functions
a) Simplified wiring with built-in power relay.
The unit is internally provided with a power relay to get simpler wiring than ever before. If the key switch terminal AC,
ground cable or any other parts is wrongly connected, the starter (5) stays off. This helps identify wrong wiring more
easily.
b) With the output terminal for confirming engine start (Relay drive possible).
The unit has an external output terminal in order to confirm an engine start. An external relay (6) may also be
connected to this terminal. (Output current : below 200 mA)

(2) Basic Circuit

M-6
DIESEL ENGINE
(1) Alternator
(2) Key Switch
(3) Slow Blow Fuse
(4) Battery
(5) Starter
(6) External Relay
(7) Starter Auto Reduction Unit
W1014160
KiSC issued 10, 2009 A