Have you switched to plugs in PTD yet?

Jon Lawson

Are you still using screw terminations, or have you switched to plugs yet? Oliver Semling encourages engineers to make the right choice

In the power transmission and distribution (PTD) sector, a comparison of screw terminations and plug-in connectors shows the clear advantages of the latter, especially in terms of installation speed and reliability. Every minute counts for energy system operators, so they are very interested in keeping shut-off times during maintenance as short as possible. However, screw terminations are still all too common in the PTD sector.

Consider the range of plug-in connectors for PTD applications offered by Stäubli Electrical Connectors. The firm has been a technology partner for companies that handle the transmission and switching of high electric power for 60 years. With standard fork plugs for busbars, Stäubli covers the performance range up to 2,000 A. Possible applications exist in AC-DC and DC-AC converters, filters, power modules, power supplies, DC-DC converters, frequency converters and other equipment in racks. The devices are usually mounted on rails, but the plug-in connectors allow them to be replaced quickly and easily. The uses of fork plugs for busbars also include data centres and manufacturers of energy storage systems. Plug-in connectors simplify installation and maintenance, save time, and guarantee constant electrical connection values over many decades.

Obvious advantages

The advantages of plug-in connectors are evident, even just for saving space and time. With screw terminations, space must be provided for technicians to screw the module connections to the busbars. The work requires concentration, since falling screws, washers or nuts can cause dangerous short circuits. In contrast, if plug-in connectors are used, the connection is established automatically when the module is inserted into its operating position. No one needs to access the back side. This allows for saving valuable space in the frame as well as for significant reduction of downtimes.

The GSR5 series fork plugs from Stäubli are suitable for connecting rack mounts to 5mm thick busbars. For the North American market, the company offers fork plugs to the respective standards. The actual contact element in the fork plugs is the Multilam technology. This proven contact technology provides the high performance, low contact heating and guarantees reliability throught the entire lifespan of the plug. The fork plugs are designed for operating temperatures up to 150°C. The plugs can handle loads up to 400 A. Power is supplied through either a crimp or screw termination. They are available both uninsulated and with insulating housing.

The GSRD double fork plug range is suitable for connecting busbars to each other, but can also connect power modules to bars. The solid aluminum spring contact plates are also equipped with silver-plated Multilam contact technology. These plugs are available in different standard widths for busbar thicknesses of 5, 6.35 and 10mm, which have rated currents up to about 1,490 A. For connection with 15mm thick busbars, Stäubli has introduced the HP-GSRD series for currents up to 2,000 A with a width of 130mm. However, the current values indicated require that the busbar contact points are silver-plated.

Fork plugs with Multilam guarantee consistent contact quality, even through numerous mating cycles. The GSRD series, for instance, is designed for more than 1,000 mating cycles. 

Oliver Semling is with Stäubli Electrical Connectors

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