Zetor Proxima Plus Series Operator's Manual page 13

ELECTRIC INSTALLATION
50. No additional modifications of electric installation of the tractor shall be carried out (such as connection of other elec-
tric appliances) due to its possible overloading!
51. Values of electric installation:
Nominal voltage
Grounded minus
Use of starting trucks or other auxiliary sources with a different voltage or polarity may cause serious damages to the tractor.
52. When manipulating with the battery pay special attention and avoid short circuits. The tractors are equipped with a battery
disconnector that shall be switched off before any manipulation with the battery.
53. The tractors cannot be operated with disconnected battery; this may cause serious damages to the tractor.
SAFETY INSTRUCTIONS FOR THE USERS
12 V =
( - ) pole
12