6.0 Alternator output cycle?

[suprdtydvr]

Does anyone know for sure(proof?) if the alternator has a delay time associated with engine start-up(either diode gate or relay). I read somewhere that the glow plug cycle was taken out of the battery on start-up due to the large current draw then the alternator was placed on line after the glow plug cycle was complete. Looking back I am unable to find technical reference and am left with personal observation of my truck on start-up.

 

[blacksnapon]

from the 05 workshop manual

The charging system is a negative ground system consisting of the following:

generator(s)
internal voltage regulator
charging system warning indicator
storage battery
necessary wiring and cables
Generator

The generator is belt-driven by the engine accessory drive system.

The single generator system consists of the generator mounted on the top right of the engine (diesel) or top center of the engine (gas). The gas engines use a 3G 115-amp generator with a 2.71:1 pulley ratio. The 6.0L diesel engine uses a 6G 110-amp generator with a 2.79:1 pulley ratio.

The dual generator package consists of an upper/lower dual generator system. The 6.0L upper generator is a VR42 140-amp generator with a 2.79:1 pulley ratio. The 6.0L lower generator is a 4G 120-amp generator with a 3.00:1 pulley ratio. The upper and lower generators are not interchangeable.

In the single generator system, with the key in the ON position, voltage is supplied through the instrument cluster warning indicator I circuit to the voltage regulator. The regulator grounds this circuit and the charging system warning indicator is illuminated. When the engine is started, the regulator removes the ground on this circuit and the warning indicator turns off.

On the dual generator system, the PCM controls the charging system warning indicator and commands the lamp on if the PCM detects a concern on the monitored circuits.

The dual generator system is also monitored and controlled by the PCM. The PCM monitors both the upper and lower generator I circuits to determine the output of both generators and sets possible diagnostic trouble codes (DTCs). The PCM controls the lower generator by turning it off when the glow plug system is commanded on by the PCM to avoid possible damage (excessive voltage) to the glow plugs. As soon as the glow plug system stops cycling, the PCM powers up the lower generator.

The dual generators operate independently of each other. The control is through the internal voltage regulators. If one generator fails, the other generator can maintain system performance under light load conditions. Under a heavy load, the PCM detects a concern, sets a DTC, and illuminates the warning indicator.

The set voltage varies with temperature and is typically higher in cold temperatures than in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.

Battery

The battery is a 12-volt direct current source connected in a negative ground system. The battery case is sealed and includes 2 vent holes to release gases. The battery has 3 major functions:

engine cranking power source
voltage stabilizer for the electrical system
temporary power when electrical loads exceed the generator output current

 

[suprdtydvr]

here is what I get outta that.

Soooo... it looks like on s/u the glow plug demand just exceeds the ability of the voltage regulator to boost the field strength to maintain ~13.5 volts hence the lower system voltage during the glow plug cycle(given that the PCM only controls the lower alternator on a dual system and presumably has nothing to do with a single alternator system?).

 

[Beachbumcook]

Who's on first?

What's on second?

And I still don't know what the heck Vince was talking about!!!!