Starter Auto Release Control - Kubota KX91-3a Workshop Manual

WSM Minor Change

3-20 Starter auto release control

1. Outline
1) If the key freezed in the start position, the auto release relay is turned OFF to prevent damage to the
starter motor. At the same time, the glow relay will be turned OFF forcibly to prevent damage to the
glow plug. (Prevention of startor motor from key freezing)
2) The start of the engine is judged from the engine revolution sensor signal to turn OFF the auto
release relay. (Starter auto release)
3) If the key is turned OFF once and reset to the start position immediately while the engine is starting,
the pinion gear will engage while the ring gear rotates, which deteriorates the durability of the gears.
Therefore, the mechanism is designed to prevent of the engine from starting in two seconds after the
key is turned OFF. (Reentry prevention control)
4) The engine on the KX41-3 does not start at low temperature unless the revolution rises approxi-
mately 800 rpm. Therefore, the start of the engine is judged at 1,000 rpm.
(The judgment of the release of the starter has been raised by 200 rpm.)
As for the other models except KX41-3, the start of the engine is judged at 800 rpm.
5) If the key freezes while there is a failure in the engine revolution sensor, the auto release relay will be
automatically turned OFF in 30 seconds and power supply to the starter will be stopped. (Prevention
of starter burnout damage)
The reason the above period is set to 30 seconds is that it will be possible to start the engine by
energizing the starter three times for 10 seconds after auto glowing even in winter at a temperature
as low as -17 °C.
6) As shown in the diagram, if the meter panel is damaged or the or the couplers of the meter panel are
disconnected, then engine won't start.
Just because the auto release relay is Normally Open type and so battery current won't be supplied
to the strater moter. This is also for the safety.
OFF
START
AC(ON)
SAFETY SW
R&L
5V
rpm
Meter panel (CONTROL UNIT)
AUTO RELEASE RELAY (NO)
II-141
II Service Engineering Section
STARTER
MOTOR