Relay And Fuse Operating Faults; Diodes And Rectifiers - Stiga MPV 320W Workshop Manual

WORKSHOP MANUAL
MPV 320W / 520W

7.2.7 Relay and Fuse operating faults

The machine has several fuses and relays, col-
lected in a box, accessible by tilting the driver's
seat.
The table shows the functions of
each component and the effects
resulting from an anomaly with re-
spect to the contacts of the relays
shown below.
Component
F1 - Fuse 20 A - General
F2 - Fuse 20 A - PTO Clutch
R1 -Ignition consent relay from PTO
R2 -PTO safety switch relay
R3 - Ignition consent relay from safety
switches
R4 -Engine switch off relay with key
R5 - Hour counter relay
R6 -PTO relay
R1 -Engine switch off relay from the seat
R3 - Engine switch off relay from safety de-
vices

7.2.8 Diodes and Rectifiers

Diodes are solid state, semiconductor devices. They contain no moving parts and conduct current
better in one direction than the other.
• Diodes - Diodes allow current to flow through one circuit without "backing up" into another. In
engine alternator circuits, a diode is used to convert current which flows back and forth (AC) in
a circuit to current which flows only in one direction (DC). A device which converts alternating
current to a direct current is called a RECTIFIER. A diode is one type of rectifier.
Chapter
7 - ELECTRICAL SYSTEM
R1
R4
F1
F2
Effect generated by an anomaly
Nothing works
The clutch does not work and the blades do not engage
• If contact 30 remains stuck to contact 87, the engine will not start
• If contact 30 remains stuck to contact 87A, the engine will start with
PTO ON
• If contact 30 remains stuck to contact 87, the PTO is always ON
• If contact 30 remains stuck to contact 87A, the PTO does not work
and if engaged it switches OFF the engine
• If contact 30 remains stuck to contact 87, the engine will not start
• If contact 30 remains stuck to contact 87A, the engine will start with
the operator on the ground
• If contact 30 remains stuck to contact 87, the engine will not switch
off using the key
• If contact 30 remains stuck to contact 87A, the engine will not start
• If contact 30 remains stuck to contact 87, the hour counter will not
work
• If contact 30 remains stuck to contact 87A, the hour counter will
always work
• If contact 30 remains stuck to contact 87, the PTO is always ON
• If contact 30 remains stuck to contact 87A, the PTO will not work
• If contact 30 remains stuck to contact 87, the engine will start with
the operator on the ground
• If contact 30 remains stuck to contact 87A, the engine will not start
• If contact 30 remains stuck to contact 87, the engine will not start
• If contact 30 remains stuck to contact 87A with the PTO ON, the mo-
ment the engine basket is opened it does not switch off
EDITION
R5 R2
PAGE
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64
R3
R6
R3
R1