A frequently underappreciated aspect of an appliance is its connectors. In some instances, the basic connector design has not changed in 25 years or more, even though the manufacturers are developing internet-connected and automatically controlled equipment for the appliance itself.
Consequently, appliance makers strive to provide solutions offering increased reliability and
functionality, security, and ease of use. TE Connectivity’s new Power Triple Lock (PTL) connector solution offers a range of interconnections for advance technology appliance, industrial control and other applications, including free-hanging cables, panel-mounted interconnects and PCB connections.
Reliability is a primary concern in appliance designs. Designers request connectors with improved contact retention and verification of proper seating of contacts within connector housings. They also look for improved connector mating and latching as well as verification of latch engagement, the mating connector position assurance and ease of repeatable operation, ergonomic features, and sufficient durability. Connectors need to avoid the common problem of snagging of the cable by the latching mechanism.
Pulling on the snagged wires can result in the latch being broken, allowing the connector to come loose, especially under high vibration in the application. Another issue is the amount of force needed to mate connectors with increasingly larger numbers of power and signal pins.
Power is the other primary design concern. The same connector in the appliance is frequently used for power and/or signal lines, which means that consolidating the power and signal connection is needed to simplify connectivity and machine assembly. While dealing with the signal aspects is rather straightforward, the bigger challenge is power delivery, since power for pumps and motors requires carrying higher amperage than other system components.
TE Connectivity used input from appliance manufacturers and appliance subcontractors when designing their new PTL solution. This iterative process drew upon customer feedback on design proposals. As its name suggests, the PTL has three integral mechanisms to ensure reliable connections. Additionally, several features designed into the connector family offer significant benefits compared to more traditional connectors. Figure 1 shows the PTL components of a 12-terminal connector.
Improving upon current designs, the PTL’s built-in latching capability comes from reducing two latches to a single, robust latch that makes it easier to connect and improves connector reliability. The optional Connector Position Assurance (CPA) device helps to ensure full mating of the connector and keeps the connector mated during shipment, installation or when the appliance is in use.
A second optional mechanism, the Terminal Position Assurance (TPA) device, provides secondary locking of the contact into the connector housing, providing a minimum of 15lbs. of contact retention.
The audible latch of the PTL connector provides a ‘click’ that lets assemblers know the connector halves have been fully mated.
To address the problem of snagging wires under the latch, the PTL is designed with protective ribs flanking the latch, so wires are less likely to become entangled.
The PTL connector employs a flat tab and receptacle contact design that helps to allow for low mating forces and improved ease of assembly. The connectors have a maximum mating force of 1.50lbs per contact. The contacts are free of locking lances and other delicate features that could become damaged during handling prior to insertion into the connector housing. The maximum insertion force of the contact into the housing is 3.0lbs. In addition, the PTL tab and receptacle contacts are polarized to the circuit cavities in the housing, assuring proper orientation when inserting the contacts into the housings.
Figure 2 shows a closer look at the CPA and TPA devices. The CPA’s red colour makes it easy to distinguish its presence and location in the connector assembly. The TPA has both single- and double-row configurations.
One aspect of the PTL’s versatility comes from the number of product offerings. Figure 3 shows a small sample of over 450 available PTL configurations. The line includes an extensive selection in free-hanging, panel-mount and PCB header configurations. The very broad PTL product line’s single, double and matrix position configurations with Pin 1 indication have four keying and colour options to enable visual verification during assembly.
Polarization slots and keys designed into the cap and plug housings of the PTL eliminate the possibility of mismating. Together, they prevent offset positioning to both the right and left sides, 90° rotation, reverse, offset down and reverse, offset down to corner and offset to corner and reverse possibilities.
Four key positions with different colours are available for visual verification of the correctly keyed plugs and caps. In addition, the different colour of the TPA makes it easy to verify that it is or is not on a connector. Figure 4 shows the key and polarization slot positions.
One of the important aspects of the PTL product offering is the breadth of connector plug and cap materials which are all V0-rated materials offered in four levels:
- The standard material is polybutylene terephthalate (PBT), a thermoplastic engineering polymer, instead of nylon, that provides improved service for a broad range of appliances.
- The second level is a Glow Wire (GWT, V0, NF 750C) option that conforms to the flammability requirements of IEC 60335-1 for unattended appliances with connections carrying current of greater than 0.2A.
- The third level allows high-temperature applications, such as cooking appliances, to be addressed with a true 150°C, high-temperature solution. The housing and the contacts are rated at 150°C instead of 105°C.
- The fourth level is a How Wire Ignition (HWI) option.
Since they are used in all three material levels, the TPA and CPA are both 150°C high-temperature materials. Colour coding allows a quick visual check to ensure that the right material is used in a specific application.
Developed for power/signal applications, the PTL’s product line has seven terminals that address wire size ranging from 22 to 12AWG plus double 18AWG, double 20AWG with a maximum current rating of 20A on two circuits. The 20A capability allows high-current applications to be addressed with 12AWG wire.
With improved reliability from many integral design aspects and the flexibility to address almost any standard or higher level industry requirement, the ergonomically designed Power Triple Lock platform is free from sharp corners and edges, making it a friendly choice for workers on the assembly line, while offering appliance designers a new approach for exceptional connectivity.
To make it easy for customers to implement the new PTL design methodology, high-speed termination tooling, hand tools and contact extraction tools are available. The tools support crimping prototypes in small volumes, with hand tools up to and including HDE/Ocean applicators for semiautomatic and automatic tooling for high-speed termination of contacts onto wires.
In addition to the tools required to make the transition to the newest appliance connector system, 3D customer view models provide outside shell dimensions for laying-out harness and machine designs.
TE Connectivity’s PTL connector platform provides customers with selectable options which offer a standardised approach that adds to the inherent reliability of the terminal position assurance, connector position assurance and audible latching mechanisms.