jcb EcoMAX - Battery Isolators; Starter Motor; Starter Motor Earthing Requirements; Alternator

JCB EcoMAX Engine Installation Manual
Page 34 of 64 320/A9164-1 © JCB Power Systems Ltd.
12.6.3 Battery Isolators
The use of a battery isolator allows you to completely isolate the electrical system from the
equipment battery, or batteries. You must make sure that the battery isolator hardware is
sized in accordance with the expected current demand and that it has good environmental
protection. You must make sure that the contacts in the isolator are of a good, robust design
and offer minimal resistance. You must install the isolator as close as possible to the battery
and make sure that the operator can access the isolator easily.
N NOTE: The battery isolator must not be used to shut down the machine.
12.7 Starter Motor
The geared motor on the JCB EcoMAX engine is rated at 4.2 kW for the 12 V and 24 V
systems.
The starter motor’s cranking speed varies depending on a range of different conditions such
as ambient temperature, parasitic loads and available battery charge. To ensure a reliable
start in cold climate conditions tests have shown that particular cranking speeds must be
attained (see Table 2). For successful operation below -30ºC, you need full winterisation.
12.7.1 Starter Motor Earthing Requirements
Route the battery negative cable directly from the switched terminal of the isolator (or directly
from battery negative if no isolator fitted) to the earth stud on the rear casing of the starter
motor. This keeps the voltage drop at the starter motor to a minimum and makes sure that a
high integrity earth connection is maintained throughout the equipment’s life.
A separate earth cable is also needed to earth the equipment chassis. You must connect the
earth cable from the starter motor earth stud or the switched side of the isolator (if fitted) to
the chassis. Use an appropriate fastener where all paint has been removed at the point of
connection. The minimum recommended cable cross-section is 95 mm
2
.
12.8 Alternator
The alternator is direct mounted to the engine and is driven by the FEAD system. You do not
need to adjust the alternator belt as a sprung tensioner is included in the FEAD system.
The alternator rating must be at least 25% greater than the maximum continuous electrical
machine load. Check the relevant specific product technical data sheet for the exact
alternator fitted and refer to JCB Applications department for alternative options available.
The alternator charging lamp must be of a 3 watt rating to give the correct level of excitation
to the alternator upon initial start-up.
It is recommended that the engine speed signal is taken from the CAN bus however a W
terminal is provided on the alternator for engine speed indication. The frequency is 6 pulses
per alternator revolution. The alternator speed is dependent on the effective alternator pulley
diameter. Table 5 shows the speed ratios. This signal incorporates a filter network to enable
a stable tachometer response, which limits voltage output from the terminal to 1.5 Volts.
Table 5: Alternator speed ratios
Effective Diameter (mm)
Alternator: Engine speed ratio
50
3.113:1
56.2
2.787:1