D. Preglow System With Preglow Indicator Lamp (Model 123.1)
Operation of Preglow SystemD. Preglow system with preglow indicator lamp engine 615, 616 in model 123.1
Operation
The preglow system is switched on by pulling preglow starter switch into position I. The preglow indicator lamp lights up as long as preglowing continues.
The glow plugs are connected in series and protected by a 50 amps fuse.
The preglowing current of approx. 50-60 amps is determined by the firm resistances of the glow plugs, as well as by the resistance conductors.
Too high a preglowing current is the result of a ground connection or short-circuit in preglow system, e.g. a defective glow plug.
Too low a preglowing current is the result of transition resistance caused e. g. by a loose glow plug connection or by an insufficiently charged battery.
The preglowing time depends on the ambient temperature and the coolant temperature and can be set at will. For the cold engine, the following preglowing periods are reference values:
Ambient temperature +20 °C approx. 10 seconds
Ambient temperature 0 °C approx. 20 seconds
Ambient temperature - 5 °C approx. 30 seconds
At lower temperatures pertinently longer up to max 1 minute.
The preglow indicator lamp lights up as long as the preglow system is actuated. It is contacted with plus by means of the reed contact located in parallel with fuse. The reed contact is closed if the available glow current is adequate. Minus of indicator lamp is continuously connected to ground.
The engine is stopped by pushing preglow starter switch down.
Mechanical speed increase is effected by turning knob on preglow starter switch.
Turning counterclockwise = higher speed
Turning clockwise = lower speed