Baroness LM551, Service Manual, Page: 127 / 213

Relay 4/Starter
Operates with other relays when specific
conditions are met, to ensure safety.
Connected to the starter, and controls the
electrical circuit to the starter depending on
the relay operating conditions.
Relay 5/Neutral
Operates in coordination with the proximity
switch/neutral, and is one of the parts that
controls engine start, driving and stop, and
the alarm buzzer.
Relay 6/Brake switch
Operates in coordination with the proximity
switch/parking brake, and is one of the
parts that controls engine start, driving and
stop, and the alarm buzzer.
Relay 7/Maintenance
Operates in coordination with the reel
forward/reverse switch, and is one of the
parts that controls engine driving and stop.
Relay 8/unit position detection
Related to rotation of the front mower unit
reel cutter.
It is installed to operate the reel cutter after
detecting that all front mower units are
down, to ensure safety.
Relay 9/Overload detection
It is installed to activate the alarm buzzer
and prevent overloading the engine and
piston pump by detecting that the traveling
pedal is pressed with the front mower reel
cutter rotated.
Relay 10/#4 down detection
Related to the #2, #3 mower unit delay
when lowering the mower units.
It is installed to operate the rear mower unit
down after detecting that the front mower
unit has been lowered.
Relay 11/#2, 3 up/down SOL
Related to #2, #3 mower unit up/down.
It operates the #2, #3 mower up/down
solenoid in coordination with the operation
of the on delay timer. 4.
5.
6.
7.
8.
9.
10.
11.
Inspection of Relay (MR5A411A1K)
Remove the relay.
The normal measured resistance between
relay terminals 1 and 2 is about 75 Ω.
2
1
5
3
7
6
2 7
1 6
5
3
38jyg3-007
Inspection of Relay (MR5A411A1K)_001
Normal operation is when there is no
conduction between relay terminals 3 and
5, and 6 and 7.
2
1
5
3
7
6
2 7
1 6
5
3
38jyg3-008
Inspection of Relay (MR5A411A1K)_002
Normal operation is when there is
conduction between relay terminals 3 and
5, and 6 and 7 with battery voltage applied
between relay terminals 1 and 2.
2
1
5
3
7
6
2 7
1 6
5
3
38jyg3-009
Inspection of Relay (MR5A411A1K)_003
1.
2.
3.
4.
Electrical System
LM551
Electrical System
Page 5-41
About The Electrical Components