MTZ 1220.1, Operator'S Manual

Page: 68 / 244

MTZ 1220.1/1220.3 Section D. Construction and Operation
D20
Engine Starting Interlock
As a precautionary measure against the
engine starting when the range is
switched on, the tractor is equipped with a
special interlock device (Fig. E-15.7). The
interlock consists of a switch (8) located in
the transmission gearbox casing on the
left side, balls (6) and pins (7, 7
а
).
On switching the range on, the interlock
mechanism opens the switch contacts and
breaks the circuit of the starter intermedi-
ate relay (1).
The shims (9) are provided to adjust the
instant of contact opening (9).
ATTENTION! Before proceeding to
starting the engine, set the transmission
gearbox speed-range change-over lever
to its neutral position!
Fig. D -15.7. Diagram of interlocking the engine starting:
1 – starter; 2 – alternator; 3 – interlock relay; 4 – starter switch; 5 – starter relay; 6 – interlock mechanism
balls; 7 – pin; 7a – lock; 8 – unlock switch; 9 – adjusting shims; 10 – range switch-over dogs