Electrical energy meters have various sizes, shapes and terminal connections. Is it possible to have a universal quick connector for connection of all kind of meters?
Before electronic meters came to the market the meter connections had much less variants. Each terminal was made from brass with two screws to fix the conductor. The picture shows the view from the meter terminal bottom. Depending on the pin-design the quick connector touches either the screw or the screw and the inside of the brass terminal with a certain force (about 30 N for a maximum current of 60 A). The DIN 43857 gives a hole diameter of 6.5 mm for 60 A meters.
For higher currents you can find terminals with diameters of 8.5 mm or 10.5 mm. For CT- and CT/PT connected meters you have diameters around 4 mm.
So, to cover direct connected meters and transformer operated meters with one quick connector is not possible. The connector pin diameter must match with the maximum current. Otherwise the heat (coming from the resistance) will destroy either the terminal block or the quick connector.
For this reason a test bench used to have:
- a set of quick connectors with 6 mm pins to cover 60 A long duration or 100 A for short duration (< 2 minutes, 20 % duty cycle)
- a set of quick connectors with 4 mm pins for transformer operated meters
- a set of wires for direct connected meters > 60 A
Since electronic energy meters are in the market, we have also to deal with cage lifting terminals. The photo shows the view from the meter bottom.
Cage lifting terminals have neither a screw to touch, nor conducting material at the bottom. Therefor a round pin has no touching point to connect the current.
For all kind of ANSI socket type meters are also different adapters or quick connectors required.
What about universal quick connectors for voltage?
If the voltage is supplied via the secondary side of Insulated Current Transformers there is no need for a separate voltage quick connector. This applies for direct connected polyphase meters. For direct connected singlephase meters with Multi Secondary Voltage Transformers is also no need for a voltage quick connector.
For CT- and CT/PT meters a universal quick connector would require pins which can be moved and fixed in all 3 axes.
We can do all kind of quick connectors, including voltage, auxiliary circuits, pulse outputs and communication. But we can’t combine everything in one quick connector.
We would really like to solve your meter testing problems, especially for huge meter quantities. With our high degree of automation or with manual operated test benches we can cover the real needs.
Please ask us for more information or let us know your comments.