Any electricians understand why Aeotec smart switch should not be used for fans or motors?


(Ron) #1

TheSmartestHouse lists the Aeotch Smart Switch Gen 6 as not being safe for fans or motors.

“Works with resistive loads only with 15 Watts on load minimum (don’t use with inductive loads like fans and motors!)”

I am using it on an extra refrigerator I have to turn it on once in a while to keep it fresh and functioning. Seems to have been working fine for months. Just curious what this warning is about. The plug is rated for 15amps. It’s plugged into a 15amp socket so if it tried to pull more it would trigger the breaker. Is there something more to consider about the load. I found this http://www.schneider-electric.us/en/faqs/FA111665/ but I can’t find anything from Aeotech themselves saying this is an issue. So not sure why this site says this and if it is any issue.


#2

Engineer, not electrician, but It’s the difference between resistive loads and inductive loads. They just have different physics. So even when the amperage is the same, you can burn out the switch or the motor or both.

That said, I’m wondering if @thesmartesthouse mixed up the product descriptions for the switch and the dimmer switch. The dimmer switch is not rated for inductive loads, but I believe the smart switch is. They give examples of appliances in use with it.


(Daniel Ionescu) #3

When you shut down power to an inductive load, motor still spins and generates voltage through induction. If the switch is electronic and not protected, it can be damaged by the uncontrolled transient voltage.


(Ron) #4

Interesting, in this post http://forum.micasaverde.com/index.php?topic=14974.0

someone proposes that for something you don’t typically shut off, like in my case a refrigerator, it might be OK to use. But I am wondering if the compressor and/or fans are turning on/off isn’t that the same issue?

In my use case I turn on the refrigerator 1 hr every day to keep it from getting stale and moldy inside. It’s been working great and I imagine it never reaches temp during the hr so it keeps working hard and then gets turned off by the switch cutting off power. Maybe my unique case is OK?


#5

That same post says:

Disclaimer: This is a theory only.

The guy’s theory is wrong. If it’s not rated for inductive loads, you shouldn’t use it with them. Because even a power outage can create the problem. :wink:


(Ron) #6

Yea, I noticed his disclaimer that is why I posted back here instead of taking his word :slight_smile:

I have another of these devices on a wine cooler that’s been running for a few years now but it is the older model.

This one

So now I have to replace both of them :frowning:

Dam, I have another of the newer Gen 6 on a Space Heater which are supposed to be OK but now I realize that the space heater has a build in Fan!

Anyone want to buy three of these switches haha


#7

I don’t see any warnings posted for the older energy monitoring switch, maybe @TheSmartestHouse knows if they’re rated for appliances or not.


( I hate Mondays) #8

Daniel’s right. There’s also the start up current that needs to be taken into account - physics says that static friction is stronger than the dynamic friction. When you push a piece of furniture, it takes a lot more effort to get it started than to keep it moving. Same applies to motors - it takes a lot more energy (read current) to get a motor to start than to keep it moving - which may well exceed the rated amperage of a switch - listen to your A/C starting for example, you’ll hear the slight buzz when it starts - that’s a current surge needed to get it started. Both starting and/or stopping an electrical motor can damage the switch.


( I hate Mondays) #9

Yeah, the compressor is technically a motor - and a very rough one too :slight_smile: his theory is completely off - you don’t need to turn the fridge on/off - it does it itself, many times a day… about 10-50 times a day…


(Ron) #10

That is what I was thinking. Now I just need to figure out if TheSmartestHouse is correct because Aeotec doesn’t mention this anywhere. I have contacted Aeotec support to see what they say.


(RH) #11

Of course you should check with the manufacturer, but the site specifically mentions refrigerators as acceptable. It also has protection designed in for the switch, the load and the source. That’s what it says anyway. Interesting for such a small device.

-from the site

Safety.
Turn your electronics off in the event of an emergency or a hazard. Smart Switch 6 lets you automatically turn off devices, such as leaking air conditioners and fridges, when they fail.


(Ron) #12

It looks like The Smartest House has it wrong this time. I contacted Aeotec support and received a reply right away. And that reply came from someone I worked a lot with in the past when I wrote a DH for one of their products. He assured me the new ZW096-A02 model works fine with inductive load. He wasn’t sure about the older DSC06106-ZWUS model but thought at worst it would make the unit fail and not be a fire hazard. I have been using this device on my wine cooler for almost 2 years so I think it is fine.

Here is the full reply…

Unfortunately i don’t know too much about the DSC06, but i know that it isn’t restricted to resistive loads, other load types should be accepted here. The document is a bit lacking for this older device.

But I am very sure that the ZW096 is universally compatible to all load types as long as it does not exceed the maximum current. I don’t know why they are listed as such by this vendor. I can currently say that I use a 400W fan on my Smart Switch 6 for over a year without any issues to automate the fan load.

A wine cooler shouldn’t be an issue, while it may depend on the total current required by the refrigerator, I have heard success by other users.

I can say it definitely is not a firehazard. At the very least, if the DSC06 is not compatible, the unit will stop working over time quickly.


#13

Our disclaimers come from servicing products under warranty and user feedback so based on our experience with the NEW Aeotec switches (Smart Switch 6), they don’t work well with motor loads. DSC06106 and even the 2nd gen DSC24 worked well with large appliances because they could accept high inrush current (something @ady624) mentioned. We received many complaints about failed Smart Switch 6 from customers who tried to use it the same way they did with DSC06106. This is how we figured that the new Smart Switch 6 had a different structure and would often fail when used with devices which draw more power at start-up (that’s why some users say it’s OK to use these with something that’s always on because then the power stays at more-less the same level they’re rated for as opposed to spiking up high when the motor starts).

One thing to remember is that there’s a difference in power drew by inductive loads / appliances at 220V (Europe or China) and 110V. We found that where most 220V Z-Wave plugs and switches work great with large appliances, they fail over time or right away when used with 110V. Since Aeotec and many others manufacture (and test) their devices in China, their findings will not always apply to US standards.

BUT because Aeotec doesn’t mention this limitation in their documentation, you should be able to get the unit replaced under warranty (if it fails within 12 months). As mentioned before, we put the disclaimer in the description after reviewing warranty service claims and user feedback within the U.S.

We also released the Zooz ZEN15 Power Switch based on the demand to control heavier inductive loads:


(Daniel Ionescu) #14

With 220V AC current is roughly half of the equivalent power for 110V AC. Inductive loads can have an inrush current of up to 300% of nominal. That’s what affect electronics. And the damage is not on startup, when current lags behind voltage, but on shut down when voltage lags behind current while most controls operate on voltage variation.


(Ron) #15

Thanks for clarifying, you folks should inform aeotec about these findings. They don’t seem to think there is any issue.


#16

We forward all feedback to the manufacturers and requested for the documentation to be updated numerous times, that’s why we finally put the disclaimer on our website since there were no changes made to the manual. The issue was never addressed in the device design itself (since the manufacturer never acknowledged the problem) so we had to develop our own alternative product :wink: