How does the ST-3/XT3 work?
ST-3/XT3 : Transformer Rated Wireless Site Tester
This unit is a socket type tester, that obtains the reading directly from the secondary of the current and potential transformers.
- It does not require any external load to perform tests and it is powered up by the installation.
- The back of the unit is easily configurable to accommodate the different meter installations using removable twist-tabs that does not require any tool to install.
- A form selector switch can be toggled to select the proper form of the installation. The unit is lightweight for ease of configuration and operation.
- The accessories are plugged in the front of the unit with a 12-pin port connectors. The unit can perform tests on all three phases simultaneously. The accessories have an electronically compensated interface linked to 3 Rogowski cables (figure 1) for CT testing or 3 banana plug (figure 2) end cables and alligator clamps for PT testing.
- The accessories can be plugged in the front of the unit prior to installing the tester in the meter socket.
- Once the tester installed, the only manipulation left is to hook the Rogowski cables around the CTs and the clamps to be clamped to the PTs.
The tester can be controlled from a safe distance using a device such as smart phone, tablet, or laptop.
For overhead installations, another accessory is available that acts as an interface between the HV Probes (Sensorlink) and the tester.
Cables extensions (50 feet and 100 feet) are also available for use with the CT and PT accessories when CT and PT are further than 15 feet away from the meter socket.
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