Technical report on switches.

05-09-2019 - Reports

Technical report on switches.
 

Switches

 
A switch is defined as an electrical or mechanical device that allows an on/off function to be performed. Its function is centered on letting the current pass through a given circuit.
 
1. What types of switches are there?
1.1. Pressure switches and oil pressure transmitters
1.2. Stop light switches
                1.2.1. Mechanical stop switches
                1.2.2 Hydraulic stop switches
                1.2.3. Pneumatic stop switches
2. Clutch pedal switches
3. Resistance thermometers
                3.1. NTC (Negative Temperature Coefficient)
4. Temperature switches
                4.1. Alarm temperature switch (temperature)
                4.2. Fan temperature switch (radiator)
5. What are the most common temperature switch malfunctions?
6. Reverse light switches
7. How are FAE switches manufactured?
8. What are the most common switch malfunctions?

 
 
1. WHAT TYPES OF SWITCHES ARE THERE?

Within the switch designation, FAE groups different families, which behave very differently and have opposite functions.
 
Segmentation of switches by families.


All these references can be found in the Ci2 catalogue. All in all, FAE makes more than 900 references available to the customer.

 
1.1. PRESSURE SWITCHES AND OIL PRESSURE TRANSMITTERS

Its function is to indicate the existence of oil pressure in the engine. As soon as the pressure switch reads the minimum oil pressure level or the absence of it, it activates its circuit by means of a pilot light
 
 

FAE Pressure switches and oil pressure transmitters.
 
Each of these devices is calibrated to a specific actuation pressure. This calibration pressure is regulated by an internal spring in the device.
 

1.2. STOP LIGHT SWITCHES

Its function is to turn on the taillights of the vehicle when required. In this case, when the brake pedal is activated. Within this family we can find 3 types:
 
1.2.1.  MECHANICAL STOP LIGHT SWITCH
 







FAE Mechanical stop light switch

They work on the basis of pressure on a push-button that produces a contact which lets the electric current to pass.


 



1.2.2. HYDRAULIC STOP LIGHT SWITCH
 

FAE Hydraulic stop switch

Its function is similar to that of a pressure switch with the difference that this device is installed inside a hydraulic circuit (inside the brakes) and its mission is to warn at a certain pressure level. If the pressure falls below the minimum value, a pilot is activated.



 



1.2.3 PNEUMATIC STOP LIGHT SWITCH
 
FAE pneumatic stop switches

The operation is identical to a hydraulic switch but, in this case, the circuit in which it operates is pneumatic.



 



 
2. CLUTCH PEDAL SWITCHES

 

FAE clutch pedal switch
The clutch pedal switch makes a mechanical contact as soon as it senses the pressure when the pedal is pressed down. Some of them are also used to switch off the speed control.


 
3. RESISTANCE THERMOMETERS

The resistance thermometer uses the heat of the coolant as an electrical signal. There are two types:
 
3.1. NTC (Negative Temperature Coefficient)

 

FAE NTC resistance thermometer
The higher the temperature, the lower the resistance.

 
4. TEMPERATURE SWITCHES

This type of switch is installed in the refrigeration circuit, usually in or near the radiator. As soon as it registers a temperature variation, it is activated. There are two types:
 

4.1 ALARM TEMPERATURE SWITCH
 

FAE 
Alarm temperature switch (temperature)
 

It is a system that carries out a control of the temperature of the engine. It informs the driver of an abnormal state of the engine temperature by activating a light signal on the instrument panel when the engine exceeds the calibration temperature.




4.2. FAN TEMPERATURE SWITCH (RADIATOR)
 

FAE Alarm temperature switch (radiator)
The function of a temperature switch is to maintain the temperature at certain levels through the use of the radiator fan. This keeps the engine at an optimum operating point.



 
5. WHAT ARE THE MOST COMMON TEMPERATURE SWITCH MALFUNCTIONS?

In case of the temperature switches, the most common malfunction symptoms are the following:
  • High fuel consumption.
  • Power loss.
  • Overheating.
  • Check Engine light indicator is on.
  • Difficulties in starting.
  • Increase in pollutant emissions.
6. REVERSE LIGHT SWITCHES

 

FAE Reverse light switches
The reverse switch makes an electrical contact which, when engaging reverse gear, opens the current flow so that the taillights can be switched on. These switches are located in the gearbox.​
 


 
7. HOW ARE FAE SWITCHES MANUFACTURED?
 
FAE has been manufacturing switches since 1972, so it has enough experience to provide the customer with a quality product that meets all the requirements of the automotive industry.
 
These devices are manufactured at FAE's facility in Cervera. To be able to produce these devices, FAE has injection machines with inserts at its disposal. During the manufacturing of the switches, several molds are used, in some cases up to 5.
 
As this is a delicate stage in the manufacturing process, FAE has a team of more than 30 engineers who develop the different types of switches.
 
In order to meet the stringent requirements within the automotive industry, FAE uses the same components and materials as OEM products.
 
These switches are tested at the Barcelona facility. FAE verifies 100% of its switches to ensure the correct operation inside the vehicle.
 

8. WHAT ARE THE MOST COMMON SWITCH MALFUNCTIONS?

The main causes of a switch malfunction are the following:
  • Cracks or breaks. Tensions caused by mechanical tension.
  • Deformations and dents. Switch overheating.
  • Malfunction. Bad anchorage to the brake pedal support.
  • No signal. Cable breakage due to friction or excess vibration, short circuits, internal breakage of the switch due to mechanical or thermal stress.