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Lights connected to Insteon switches flicker when running on generator power

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  • Lights connected to Insteon switches flicker when running on generator power

    I've seen this discussed on other forums, but I never found a solution or even a solid explanation I believe.

    I have 25 or more hard wires switches (dimmer and on/off) and a similar number of plug-in modules throughout my home. They are powering a combination of LED and Incandescent bulbs. I've had a couple hubs and a PLM attached to a PC protected by a UPS.
    I also have a Generac 20Kw whole-house generator with auto-transfer switch.

    I don't have power failures anymore, but since installing the majority of my switches , when I've lost power and run on the generator I notice the lights connected to Insteon devices flicker and flash (a longer flicker) periodically and seemingly randomly. I'm not the only one who has experienced this.

    I have turned on/off heavy loads and that doesn't appear to be a direct correlation.

    It was suggested on another forum that the lights flicker with Insteon traffic. They suggested turning on the traffic indicator and watching it flicker with the lights. While it does flicker with the lights, the traffic indicator also flashes when the lights are on steady. Turning lights on/off will generate traffic I can see on the indicator, but doesn't cause the lights to flicker. I think this proves there is no direct correlation between insteon traffic and the lights flickering.

    Others have suggested that it's the type of generator that is causing the problem - that a Honda Inverter generator resolves the issue. However, I can't believe that my whole-house generator is not producing a clean sine wave. I'm not sure how to communicate this issue to my generator dealer since he's not an Insteon user.

    Has anyone else had this problem? Has anyone else resolved the problem? This is really irritating during long outages and has suddenly made Insteon look like X10 to my wife... Which is not good.

    Thanks in advance.

  • #2
    You will want to understand the differences between the two types of generators first.

    A conventional generator is really just a motor hooked up to an alternator to produce a desired AC output and frequency. If the load increases the generator will rev up to accommodate the extra draw but will not do any smoothing of the sine wave. Its job is to simply provide current. This is good for traditional, robust electrical devices but not recommended with anything that uses a microprocessor, or chip, as operation could be impacted.

    And invertor generator, or invertor, or pure sine wave generator, starts off the same but then converts the AC to DC, smooth's out the sine wave and then converts/inverts it back to AC. The creates consistent power for electrical consumption. Its job is to provide clean and consistent power. This is good for any of todays electronics.


    A conventional generator will have some issues with Insteon. The first issue that most people experience is bad communication, or reliability. Insteon has a timing chip that measures the sine wave and places the control messages right at the zero crossing of that sine wave. As the conventional generator revs up, or down, that zero crossing is no longer in the same place and so the messages land in the wrong spot and get lost.

    Another issue is that most IoT devices are power stealing. Since the devices are taking AC power and converting it to DC any fluctuation the electrical current is going to impact operation.

    The pure sine wave generator fixes both issues by making sure that both the electrical current and frequency are delivered according to spec.

    You should be able to ask your dealer if what you bought is a true sine wave generator. If he cannot answer you may need a new dealer.


    • #3
      Honda Generators also cost about 10X more. I too have a GEnerac 20KW, but have not yet lost power (good thing). Of course the Generac is advertised as it has a clean output and good for sensitive electronics. it still has about 7% distortion compared to the Honda at less than 1%.


      • #4
        I have a 7kw portable generator (non-inverter) via transfer switch and was testing it after installing lots of insteon switches, etc... in my home.

        I am seeing the same issue. Whenever I hit an insteon light switch, LED lights throughout the house blink rapidly while the switch is transmitting state changes to other switches an my hub.

        This is really bad, if I need to run on generator I don't really care if linked switches are updated correctly or my hub or home automation works correctly, however I do care that the insteon switches are transmitting signals that could damage or reduce the lifetime of equipment in my home including other insteon switches, LED lights, appliances, electronics, computers, or the generator itself.

        I have not hooked up a scope to the AC lines to get a waveform for what is occurring during these transmissions, but I am concerned about damage to thousands of dollars of equipment that is powered by the generator.

        One thought would be to disable powerline communication and do only RF (not sure if that is even possible via config)?



        • #5
          I'll throw my 2 cents in here. Background: I was 40 years in public safety communications systems with very expensive and sensitive equipment in remote sites running off both backup battery power and automatic standby generators.

          Standby generators are basically constant speed (RPM governor regulated). The voltage is regulated by feedback to the field windings and yes if you hit it with a heavy load there my be a slight flicker brownout but it recovers in a cycle or 2. The engine RPM does not need to change, but the throttle will open to handle the additional load. The power frequency will vary slightly with the tolerance of the engine governor but should be with +/- 2hz.

          I went Googling and could not find a standby automatic inverter generator in the 20Kw plus range. Inverter generators are more in the RV / portable use low power bracket (typically 4Kw and under). The engine RPM is controlled so that the internal generator (or alternator) produces just enough power for load. An internal inverter takes the DC (or converted AC) from the generator and converts it up-to 120Vac 60Hz. Since the engine speed is reduced at low loads, they are much quieter than a normal generator. However this is also their downfall. Plug in a heavy load and it will brown out, or maybe even cut-out. This is because the engine must speed up significantly in RPMs to increase the output of the generator before the inverter can supply the additional power. Ask any RVer who is trying to run an AC unit from a inverter generator. Many of these units have optional paralleling cables so two units can be used to start A/C units.

          Next, most modern "sensitive" home electronics are not really that picky about power anymore. Units made in the past 10+ years are likely to use light-weight switching power supplies rather than a heavy transformer. The first thing a switching power supply does is convert the AC power to DC and smooth it through filter capacitors. Most of these power supplies are built for world wide use and so have a wide input voltage (typically 80 to 280 volts). Most don't even care whether its AC or DC or what the waveform looks likes as along as the average voltage is within its operational range.

          I don't have a schematic of an Insteon switch, so I can only guess at its circuitry. The electronics inside are likely powered through a dropping resistor, filter capacitors and then a voltage regulator operating at likely 5V (maybe 3.3V). The filter caps likely have enough capacity to power the electronics through several cycles of "no power". The microprocessor is fast enough that it is likely to be twiddling it thumbs waiting for the next zero crossing.

          But I suspect a noisy Zero Crossing is where the issue comes from along with the combination of dimmer circuits and now LED lights. LED lights have their own power supplies since an LED is a current device rather than voltage. So, some observations to make:
          - On/Off (relay) switches, do the lights flicker on these? if so are these LED or incandescent lamps? If LED, try putting an incandescent bulb on the same circuit and see if the LED stops flickering. If not, try putting the LED bulb in a plug-in fixture so its not going through any Insteon switch and see if it still flickers as it maybe an issue with the LED driver circuit. Does the switch make a definite "click" from the relay, or can you hear the relay clicking and buzzing when the lights flicker? I would think a relay type switch should not give an issue.

          - Dimmer switches, same as above, are the flickering lamps LED or incandescent (on a switch by switch basis). Try adding an incandescent lamp on each dimmer switch circuit that has a flickering LED lamp. See if the LED lamps stop flickering with an incandescent lamp on the same circuit. If

          I added some dimmable rated LED pot lights along with LED rated Insteon dimmers to my kitchen. Just on regular power the lamps would randomly flicker even at full ON brightness. Adding an incandescent lamp on the circuit fixed the issue, so I added a small power resistor (10Kohm) in a separate wiring box above the ceiling. This fixed the problem for 98% of the time. There is still the odd time they will flicker at lower power settings.

          Just some things to try.


          • #6
            The presently sold Insteon Switches with the 100-270 Volt, 50 or 60 cycle rating. Have a small switching supply chip in the power supply for the power line transmitter and probably a 5 volt linear regulator for the logic. Some of the old power line only plug ins. Actually had the logic +5 connected directly to the AC Line input and all the regulation was in the negative side.