5504CMU Measurement Unit

Hello!

Does this unit have up-to-date installation instructions as any other c-bus product? Where may it be downloaded from?
Consider this unit to be included in c-bus installation. Does it supports 3-phase connection (3P + N) and proper power calculations? How the wiring should be done in this situation?

 

The Installation Instructions aren't on the web anywhere however the product brochure, which includes a wiring diagram, is available here.

The unit can measure current in up to 4 circuits and connections are by 4 separate split-core current transformers.

The unit is a Current Measurement Unit, not a full-house power measurement unit. It does not have a voltage connection and can therefore not make a measurement of absolute power or power factor. It can be configured to broadcast power readings instead of current by specifying a nominal line voltage in the set-up of the unit.

There is another thread that gives more details about the units operation here. I also suggest that you have a look at the UI in Toolkit to familiarize yourself with the unit.

 

C-Bus 5504CMU & 5100CT80 Installation Manuals.

You can download the installation instructions for the Clipsal C-Bus 5504CMU Current Measurement Unit, and also the 5100CT80 Current Transformer, from the following pages:

http://www.cleverhome.com.au/save-energy-efficiency-home-automation.shtml
http://www.cleverhome.com.au/products/manuals.html

 

Thanks. As I understood for the 3-phase connection I need 3 current trasformers installed on the 3 phase wires each. After that I can sum the 3 broadcasted values (current or mathematically calculated power) in software, and this will be the total consumption. Am I right?

 

So what about my suggestions? Is the current unit suitable for the 3-phase connection?

 

If you have a device in your network that can calculate the 3-phase power from the 3 individual current readings and you make some assumptions about the line-to-line voltage and power factor, then in theory you can use the CMU to measure 3-phase power. The 3-phase total current is not simply the sum of the three line currents. A calculation is required.

 

That's why there is the question. Assume I have 3 CTs installed on 3 phase lines plus CT on the neutral. In software I can get 3 phase currents and calculate each phase power independently with theoretical voltage and power factor. By the way, can I do that?
Then I can sum these 3 calculated values of phase power to get the total power of a 3-phase system. I calculate sum of scalar values (power), not the vector ones (currents).
Does the power widget itself support such calculations? Or at least I will get 3 graphs with 3 phase power values separately.

 

Well, it depends.

If these 3 circuits are wired as three independent circuits that just happen to be on different phases, and they are metered independently, then you can treat them independently. If, however, they are wired to a 3-phase load then you need to consider them as a whole.

In general, you cannot calculate the power in each phase independently and add them up because for perfectly balanced loads there is no current flowing through the neutral, whereas for a single phase circuits the full load current flows through the neutral. Unbalanced 3 phase loads also result in some current flowing through the neutral, the amount of which is related to the degree of imbalance between the phases.

The Wiser widget does not support these calculations. You can monitor them separately in 3 widgets. A better approach would be to calculate your 3-phase power and re-broadcast the result back on the Meausrement application as a kind of virtual power meter. Then configure your Wiser widget to look at this virtual power meter data and not directly from the broadcasts coming from the current measurement unit.

bmerrick posted about how to do this, combining the data coming from 2 measurements into a single measurement.

 

Thanks for the virtual meter idea. Will try that.

 

Is this UL'd and available in the US? If not, any such plans?