Points of attention
Installation of the current transformer, P1 side towards the power supply.
Attach the transformer with colson straps.
Connect white wire/S1 from the transformer to the positive terminal of the energy meter.
Connect black wire/S2 from the transformer to the negative terminal of the energy meter.
Correct in case of an incorrect connection by means of energy meter settings.
Check the connection of the RJ12 cable to a three-phase transformer properly, must click 2 times. See also the RJ12 cable connection section in Section 3 of this manual.
Tighten the cables that run through the transformer with cable spacers.
Types
Calculus offers the following Eastron meters:
SDM120MOD Energymeter 45A - 1F - ModBus - MID
SDM230MOD Energymeter 100A - 1F - ModBus - MID
SDM630MCT - Modbus - MID - V2 - 3F/100A
SDM630MCT - ML - 1L - MID - 3F - ModBus - 1xRJ12CT
SDM630MCT - ML - 2L - MID - 3F - ModBus - 2xRJ12CT
SDM630MCT - ML - 4L - MID - 3F - ModBus - 4xRJ12CT
SDM630MCT - MODBUS - MID - 3F - CT
SDM630MCT-RC - ModBus - Rogowski Coil - MID
Eastron SDM72D-M-2-MID Energymeter - 3F - ModBus - MID
The type of the energy meter is indicated above the screen of the energy meter.
Information about the specifications such as: 3x230/400V can be found under the screen (see image above).
Current transformers
Current transformers reduce high voltage currents to a much lower value, providing a safe and convenient way to monitor the actual electrical current flowing in an AC transmission. CTs work by converting the primary current into secondary current through a magnetic medium. They make it possible for energy meters to measure current on circuits that, if they measured current directly, would overload the meters. In general, most meters can measure up to a maximum of 100 A current before they need CTs to read higher values.
CTs are available for both single-phase and three-phase installations.
Types of current transformers
Solid core
Solid core CTs form a fully closed core. To install a CT with a stable core, the conductor must be disconnected to get it through the CT core.
Split core
Split core CTs have a "split" in the core that allows the CTs to be opened and placed around the conductor without the need to disconnect the conductor or interrupt the wiring. Simply detach the coil, wrap it around the load you are measuring, and reattach it!
Split cores are only used with the 630MCT-MOD-MID energy meter.
Split cores go from the T24/T36. This is the diameter of the opening, when the split core is attached, through which the power cable passes. So 24 mm or 36 mm.
Information about the type and specifications can be found on the CT itself.
Current direction in a current transformer
The primary current enters the current transformer on the side indicated by P1. The load must be installed on the side indicated by P2.
If the primary current enters the P2 (in the event of an incorrect connection), it is possible that the current is displayed as produced power instead of consumed electricity.
However, you can adjust the settings via the energy meter so that, for example, the P2 is detected as the input of the primary current. To do this, you need to go to the Set System Continued menu in the settings of the energy meter.
| Use Press and hold the button |
| This screen is displayed, you can change "Forward" to "Reverse" for each individual CT connection. |
| Press and hold the button |
and
to select the menu option.
to display the submenu.
Installation of a current transformer
Single-phase
Pull the power cable through the current transformer if the transformer is solid.
If it is of the split core type, you can click it onto the power cable without having to disconnect it.
Use colson straps to securely fasten the transformer.
To wire the amp meter correctly, connect the positive coil (white wire/S1) of the CT to the positive terminal of the amp meter, and the negative terminal of the CT to the negative terminals (black wire/S2) of the amp meter.
Make sure that the cables are connected correctly!
If connected incorrectly, it is possible that the current is measured incorrectly, for example when you connect the black wire to the positive terminal of the amp meter.
Also observe the connection of the N (neutral) and the GND (ground).
Three-phase
Example of a wiring diagram of a gateway + energy meter:
The energy meter passes power to the mean well HDR-15-24 power supply via the auxiliary supply ports 5 and 6, port 7 is connected to the L and port 8 to the N.
Then the gateway is connected to the power supply.
Example of a wiring diagram of the energy meter SDM630MCT-ML:
RJ12 cable connection
When connecting the RJ12 cable, make sure it is securely attached!
When you push the cable in, you will hear a first click. The connection then looks like this
After this, push the cable connection further and you will hear a second click.
If the connection is made incorrectly, the current may not be measured correctly.
For example: connect the S1 of phase L1 to the negative terminal of the ammeter.
The cables that run through the CT can be tightened using cable spacers. These are shown in the image below.
