How do auto relays work?
Although there are various relay designs, the ones most commonly found in low voltage auto and marine applications are electro-mechanical relays that work by activating an electromagnet to pull a set of contacts to make or break a circuit. These are used extensively throughout vehicle electrical systems.
How do I choose an automotive relay?
In order to meet the requirements of low operating voltage (60% rated voltage), automotive relays are generally designed with a voltage value with high power consumption, generally be less than 120% of the rated voltage.
What does 85 and 86 mean on a relay?
Output for a Relay. Realizing that 85 and 86 are the coil pins, these pins will be transferring the current through the coil. 85 will be used to ground your relay, while 86 will be connected to the switchable power.
What does 30 mean on a relay?
Understanding Relays, part 2: DIN numbers and different types of relay
| Terminal | Which Circuit? | Definition |
|---|---|---|
| 86 | Low current (control) | Relay coil + (power input) |
| 85 | Low current (control) | Relay coil – (ground) |
| 30 | High current (load) | From battery + |
| 87 | High current (load) | Output to device, normally open, pulled closed when coil is energized |
How does a relay work for dummies?
A relay is an electrically operated switch. They commonly use an electromagnet (coil) to operate their internal mechanical switching mechanism (contacts). When a relay contact is open, this will switch power ON for a circuit when the coil is activated.
Are all automotive relays the same?
The problem is, not all relays are the same. Many relays, if installed for the wrong application, could and will cause a short (Internal Relay Circuit) and most likely cause functionality issues or even damage to the vehicle computer systems.
What does 31 mean on a wiring diagram?
DIN 72552
| Contact | Meaning | Old terminal designation |
|---|---|---|
| Ignition system | ||
| 31 | return to battery- or direct to ground | |
| 31a | return to battery- 12/24 V relay | |
| 31b | return to battery- or ground through switch | 85d |
How many amps does a 120v relay coil draw?
The inrush current for a size 2 contactor with a 120 volt coil is 1.8 A and the seal-in current for the same coil is 0.25 A.
What is an auto relay?
The use of an auto relay means you can limit the installation of high current circuitry to those parts of the system to which it is essential. Then my installing relays at critical points the remainder of the circuit can be completed with more inexpensive low current components. This helps drive costs down. Everybody’s happy! How Does a Relay Work?
How many relays are there in a car?
Relays in Cars: A typical car can contain up to twenty automotive relays and they can be located throughout the vehicle. However common locations for their installation are in the engine compartment behind the kick panels and underneath the dash.
How do two contacts work in an automotive relay?
In an automotive relay with two contacts this would mean that one contact is opened while the other is closed. Different relays may have a greater/ fewer number of contacts depending on design. When an electric current is delivered to the solenoid a magnetic field is generated.
What is the basic principle of a relay?
All relays operate using the same basic principle. Our example will use a commonly used 4 – pin relay. Relays have two circuits: A control circuit (shown in GREEN) and a load circuit (shown in RED). The control circuit has a small control coil while the load circuit has a switch.