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[barkerb]

Afternoon.

I have been playing around with some X10 appliance modules, that fit behind my switches. The datasheet states that they use <1W. I have a whole house energy consumption meter, which measures apparent power (VA) - ie it assumes unity power factor. According to this, each device is using approx 15VA.

The devices are not getting warm, so there is no way they are disipating 15W of real power, so if the datasheet is correct and there is approx. 1W of real power being disipated, the power factor of each device must be almost zero - almost a pure capacitative load.

Does anyone know hoe likely this is, or what the actual electrical characteristics of these devices is?

Cheers,

Ben

[Brian H]

You didn't give the model of the modules in question but a general finding for most X10 modules.
They have power line derived power supplies with a capacitor in series with the line or neutral depending on exact model. Used as a voltage dropping element many times clamped by a Zener Diode and sometimes a reverse diode to clamp off the other 1/2 of the cycle. Sometmes a small value resistor is in series to slow down surges.

Also many have the AC Line Pin as the Common. Resulting in a big flash if you are testing them and your equipment get a earth reference. 

My Kill-A-Watt meter on a older Lamp Module is showing a PF that varies between 0.09 and 0.25. An X10Pro XPFM Fixture Module; was around 0.25 to 0.29 for a PF

I believe there are still some schematics of some modules on this web site if you are interested.
http://www.idobartana.com/hakb/index.htm
Note. The new X10 Lamp Modules and CFL rated Appliance Modules do not match any schematics I have seen posted.

[barkerb]

These are the units I have been using:

http://x10-hk.com/store/product_info.php?cPath=21_29&products_id=45

If we assume they dissipate 1W real power, 14VA, then that would give a power factor 0f ~0.07 when Idle, which from what you are saying may be a reasonable estimate.

Cheers,

Ben

[Brian H]

I downloaded the manual you linked to and will give it a look.
I am fairly sure the EU devices are similar when it comes to power supplies.