Difference between revisions of "Connectors"
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===Retention=== | ===Retention=== | ||
| + | All connectors feature some sort of retention method. For most connections in a FS car, strong retention methods (locking or tight friction-fit) are required. Only a few applications (e.g. connection between ECU and computer for tuning) may benefit from connectors with weak retention. | ||
====Friction Fit==== | ====Friction Fit==== | ||
====Locking Tab==== | ====Locking Tab==== | ||
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===Connection Method=== | ===Connection Method=== | ||
====Crimp==== | ====Crimp==== | ||
| − | + | A crimp is a mechanical connection between wire and terminal. The terminal is deformed tightly around the wire conductors, often with additional points secured to the jacket for strain relief. When done properly, this can be an incredibly strong connection - sometimes stronger than the wire itself. For this reason, most professional motorsport wiring harnesses will only use crimped joints. To achieve a reliable crimp, terminals must be properly designed for the wire gauge being used. The correct tools are also necessary; using pliers or a vise will almost always result in a weak connection that is more likely to fail. | |
====Solder==== | ====Solder==== | ||
| − | Soldering is the process of joining two or more parts by melting solder around the connection. When the solder cools, it creates a good electrical connection and | + | Soldering is the process of joining two or more parts by melting solder around the connection. When the solder cools, it creates a good electrical connection and a weak mechanical connection. Solder joints are much more brittle than crimped joints, so they are unreliable in high-vibration environments. |
====Screw Down==== | ====Screw Down==== | ||
| − | + | Screw terminals use a screw to clamp onto wires. Unlike crimp and solder connections, screw terminals do not permanently or semi-permanently fasten wires, and therefore are good solutions for applications such as an engine dyno or test bench. | |
==Types== | ==Types== | ||
===Free Hanging=== | ===Free Hanging=== | ||
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Panel mount connectors are used to allow a circuit to interface with the rest of the car. In FSAE these will usually need to be resistant to the weather. They can either be soldered directly to a PCB, or they can be connected to a circuit via wires. | Panel mount connectors are used to allow a circuit to interface with the rest of the car. In FSAE these will usually need to be resistant to the weather. They can either be soldered directly to a PCB, or they can be connected to a circuit via wires. | ||
===PCB Mount=== | ===PCB Mount=== | ||
| − | These are connectors that are soldered to PCBs. They are usually not weather resistant, and are only used inside a housing - either to connect two PCBs, or to connect a PCB to a standalone panel mount connector | + | These are connectors that are soldered to PCBs. They are usually not weather resistant, and are only used inside a housing - either to connect two PCBs, or to connect a PCB to a standalone panel mount connector. |
| − | ===PCB to PCB | + | ===PCB to PCB=== |
PCBs can be directly connected together inside a housing without the use of wires. This is usually done for modularity (so that you can use a PCB for multiple functions), interfacing with a premade part (e.g., a microcontroller), or for packaging reasons. Care needs to be taken so that the solder joints on the connectors are not being overly stressed with the weight of a PCB. | PCBs can be directly connected together inside a housing without the use of wires. This is usually done for modularity (so that you can use a PCB for multiple functions), interfacing with a premade part (e.g., a microcontroller), or for packaging reasons. Care needs to be taken so that the solder joints on the connectors are not being overly stressed with the weight of a PCB. | ||
==OEM Connectors== | ==OEM Connectors== | ||
| − | + | Many off-the-shelf parts either come with a pre-attached connector, or have a connector integral to the part itself. Some parts include a mating connector, while others will require one to be sourced. | |
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==Standard Connectors== | ==Standard Connectors== | ||
Revision as of 23:44, 18 May 2020
Connector choice is a key part of wiring harness design. Badly chosen or badly assembled connectors can often be the source of electrical issues that are annoying to fix while testing the car, so care should be taken to choose the right connector and the right tools to assemble and disassemble it.
Contents
Housing
Material
Durability
Chemical Resistance
Weather Sealing
Connectors are usually rated with an IP code. Connectors that are open to the elements (which is most of them on a formula car) will need to be rated accordingly.
Retention
All connectors feature some sort of retention method. For most connections in a FS car, strong retention methods (locking or tight friction-fit) are required. Only a few applications (e.g. connection between ECU and computer for tuning) may benefit from connectors with weak retention.
Friction Fit
Locking Tab
Screw Lock
Twist Lock
Cam Lock
Push-Pull
Contacts
Material
Corrosion Resistance
Wear Characteristics
Sizing
Ampacity
Resistance
Removable
Connection Method
Crimp
A crimp is a mechanical connection between wire and terminal. The terminal is deformed tightly around the wire conductors, often with additional points secured to the jacket for strain relief. When done properly, this can be an incredibly strong connection - sometimes stronger than the wire itself. For this reason, most professional motorsport wiring harnesses will only use crimped joints. To achieve a reliable crimp, terminals must be properly designed for the wire gauge being used. The correct tools are also necessary; using pliers or a vise will almost always result in a weak connection that is more likely to fail.
Solder
Soldering is the process of joining two or more parts by melting solder around the connection. When the solder cools, it creates a good electrical connection and a weak mechanical connection. Solder joints are much more brittle than crimped joints, so they are unreliable in high-vibration environments.
Screw Down
Screw terminals use a screw to clamp onto wires. Unlike crimp and solder connections, screw terminals do not permanently or semi-permanently fasten wires, and therefore are good solutions for applications such as an engine dyno or test bench.
Types
Free Hanging
This is probably the most common type of connector on an FSAE car. These connect wires to other wires, and can interface either with other free hanging connectors or with panel mount connectors. In FSAE these will usually need to be weather resistant. The Deutsch DT and DTM series are popular in FSAE, although many varieties exist.
Panel Mount
Panel mount connectors are used to allow a circuit to interface with the rest of the car. In FSAE these will usually need to be resistant to the weather. They can either be soldered directly to a PCB, or they can be connected to a circuit via wires.
PCB Mount
These are connectors that are soldered to PCBs. They are usually not weather resistant, and are only used inside a housing - either to connect two PCBs, or to connect a PCB to a standalone panel mount connector.
PCB to PCB
PCBs can be directly connected together inside a housing without the use of wires. This is usually done for modularity (so that you can use a PCB for multiple functions), interfacing with a premade part (e.g., a microcontroller), or for packaging reasons. Care needs to be taken so that the solder joints on the connectors are not being overly stressed with the weight of a PCB.
OEM Connectors
Many off-the-shelf parts either come with a pre-attached connector, or have a connector integral to the part itself. Some parts include a mating connector, while others will require one to be sourced.
Standard Connectors
USB
RJ45
D-Subminiature
RF Connectors
BNC
SMA
TNC
N Connector
u.FL
MCX
Considerations
Density
Connectors can vary greatly in how close together the pins are. A connector with a higher density will usually be lighter, but they can be harder to assemble.
Connect/Disconnect Cycle Rating
As connectors are connected and disconnected, the contacts and components will deteriorate. The cycle rating is how many times this can happen while still meeting the specifications for maximum resistance and pull force. Many connectors (like board to board connectors) are only rated to tens of cycles, while some (like USB connectors) are rated for thousands of insertions.
