Radiator cooling fan

RADIATOR COOLING FAN

The electric fan (1) is controlled by the two stage thermal switch (2) which, when contact (a) closes when the temperature of the coolant reaches 86° - 90°C, allows the current to pass from the battery to the electric fan (1) through the resistor (4), thereby creating the 1st fan operating speed (the lowest speed).

Contact (a) opens as the temperature decreases to 81° - 85°C, causing the electric fan to cut out.

When the temperature of the coolant reaches 90° - 94°C contact (b) of the thermal switch (2) also closes, placing the electric fan (1) circuit directly to earth thereby excluding the resistor and creating the 2nd fan operating speed (the highest speed).

When the temperature of the coolant goes down to 85° ÷ - 89°C the opening of contact (b) causes the resistor (4) to come on and the electric fan operates at the lowest speed.

Radiator cooling fan operating test at the bench

With a 12 V supply it should operate at 2700 ± 100 rpm and not absorb more than 13 A. Resistance value of resistor (4) for 1st radiator cooling fan operating speed : 0.23 ± 0.02Ω.

1. Radiator fan
2. Thermal switch
3. Radiator fan protective fuse
4. Additional resistor

HEATER FAN (type with permanent magnet inductor)

Heater fan operating test at the bench

Operating in the open air, with fan fitted, supply of 12 V:

• at 2600 ± 100 rpm it should not absorb more than 3,5 A

Near the electric fan there is a resistor to engage the second speed at a resistance value of 0,23Ω