Battery Description and Operation
| CAUTION | Batteries produce explosive gases, contain corrosive acid, and supply levels of electrical current high enough to cause burns. Therefore, to reduce the risk of personal injury when working near a battery: Always shield your eyes and avoid leaning over the battery whenever possible. Do not expose the battery to open flames or sparks. Do not allow the battery electrolyte to contact the eyes or the skin. Flush immediately and thoroughly any contacted areas with water and get medical help. Follow each step of the jump starting procedure in order. Treat both the booster and the discharged batteries carefully when using the jumper cables. |
Scheme 1
The maintenance-free battery is the standard original equipment battery. There are no vent plugs in the cover. The maintenance-free battery is completely sealed except for two small vent holes in the side. These vent holes release the small amount of gas that is produced in the battery.
The battery has three functions as a major source of energy
- Engine cranking
- Voltage stabilization
- An alternate source of energy with a generator overload.
The battery specification label contains the following
- The test ratings
- The original equipment catalog number
- The recommended replacement model number
Scheme 2
Starting System Description and Operation
The PG-260M and Hitachi-S14-100B are non-repairable starter motors. It has pole pieces that are arranged around the armature within the starter housing. When the solenoid windings are energized, the pull-in winding circuit is completed to ground through the starter motor. The hold-in winding circuit is completed to ground through the solenoid. The windings work together magnetically to pull in and hold in the plunger. The plunger moves the shift lever. This action causes the starter drive assembly to rotate on the armature shaft spline as it engages with the flywheel ring gear on the engine. At the same time, the plunger closes the solenoid switch contacts in the starter solenoid. Full battery voltage is then applied directly to the starter motor and it cranks the engine.
As soon as the solenoid switch contacts close, current stops flowing thorough the pull-in winding as battery voltage is now applied to both ends of the windings. The hold-in winding remains energized; its magnetic field is strong enough to hold the plunger, shift lever, starter drive assembly, and solenoid switch contacts in place to continue cranking the engine. When the engine starts, the pinion gear overrun sprag protects the armature from excessive speed until the switch is opened.
When the ignition switch is released from the CRANK position, voltage is removed from the starter solenoid S terminal. Current flows from the motor contacts through both windings to ground at the end of the hold-in winding. However, the direction of the current flow through the pull-in winding is now in the opposite direction of the current flow when the winding was first energized.
The magnetic fields of the pull-in and hold-in windings now oppose one another. This action of the windings, along with the help of the return spring, cause the starter drive assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter motor is turned off.
Starter/Generator Control Module (SGCM) Description and Operation
The starter generator control module (SGCM) controls the flow of torque/energy into and out of the starter/generator. Overall, the SGCM controls the starter generator's engine cranking, torque control, speed control and torque smoothing/active damping functions. The SGCM also controls the four types of power
- Perform bi-directional 36-volt DC to 12-volt DC electrical energy conversion between the 36-volt DC bus and the 12-volt DC bus for system energy management.
- Perform bi-directional DC/AC electrical energy conversion between the 36-volt DC bus and the 3-phase asynchronous machine
- Provide 120-volt 60Hz AC energy for on and off board electrical equipment.
- 28-volt AC for the starting function.
In the basic, 3-phase inversion/conversion process, 42-volt DC is converted to AC for starting, and, conversely, AC is converted to 42-volt DC for recharging. In addition, 14-volt power is converted to 42-volt for jump-starting, 42-volt power is converted to 14-volt for the battery charging function, and 42-volt power is converted to 120 volts AC for powering the auxiliary power outlets.
The SGCM has two discrete crank signal circuits inputs to calculate engine position. One is hard wired and one is a signal on the GMLAN bus. This acts as a back-up system in the event that one signal is interrupted the engine will be able to start and run although a DTC will set.