Heater
To drive the fan, an ME-255 direct current electric motor with excitation from permanent magnets is used. When an additional resistor is included in the power supply circuit of the electric motor, the armature shaft rotates at a reduced frequency. The resistor is secured with two spring washers in the heater fan housing. The resistance value of the resistor is 1.5 ohms at 20°C.
It is recommended to replace a defective electric motor with a new one. The only possible repair is cleaning the collector. To disassemble the motor, unscrew the screws securing the cover and remove it. Then the lock washer is removed from the armature shaft and the armature is removed from the housing. Assembly is carried out in reverse order.
The condition check is the same as described above for the windshield wiper motor.
Brief technical characteristics of the electric motor:
- Shaft speed when the motor is loaded with an impeller at a voltage of 12 V and temperature (25±10) °C, min-1 — 3000±150
- Current consumption at the specified load and speed, A, no more than - 4.5
Possible malfunctions of the heater fan motor, their causes and remedies are given in Table. 27.
Engine cooling system
To drive the fan of the engine cooling system, electric motors of domestic production of the ME-272 type or similar ones of Yugoslav production are installed. These are DC motors with excitation from permanent magnets. The scheme of inclusion of the electric motor is shown in fig. 165. The electric motor is turned on by sensor 4 of the TM-108 type, which is wrapped in the right radiator tank. Sensor contact closure temperature (99±3) °С, and opening (94±3) °C. Auxiliary relay 3 is installed under the instrument panel on the left side. The characteristic of the relay is given in the subsection «Lighting and signaling». The electric motor does not require maintenance, and in the event of a malfunction, it must be replaced with a new one.
Pic. 165. Scheme of switching on the electric motor of the fan of the engine cooling system: 1 - ignition switch; 2 - fuse block; 3 - relay for turning on the electric motor; 4 — the sensor of inclusion of the electric motor; 5 - fan motor.
Brief technical characteristics of the electric motor:
- Rated shaft speed when the motor is loaded with an impeller, min-1 — 2600±100
- Consumed current at the specified load and speed, A, no more than — 14