Inverter exporting to grid when using Dyson Hairdryer

[cajocars]

I have a Sofar ME3000SP which has a CT clamp to limit the export to grid. As a consequence, I have a steady import of around 5-10W. I measure this through a different device and I receive a Home Assistant notification when it exports for more than 20 seconds.
I noticed that there are a couple of appliances that cause some energy to be exported when in use: one is a Dyson Supersonic Hairdryer and another is a bread maker (it happens when it’s mixing).
What’s the reason?

 

[RCinFLA]

Poor load power factor requires tight measurement accuracy of voltage to current phasing. CT transformers phasing accuracy is degraded when load power factor is poor.

Usually inverters hold a safety margin of several amps, requiring a little forward power measured from grid to ensure the measurement accuracy does not allow back feed current.

Make sure the CT transformer sense wires is twisted pair and avoid coiling up excess sense wires in a bundle that will degrade CT output accuracy.

PS: Poor power factor is caused when there is reactive loads like the inductive load of an AC motor, or a cheap power supply with simple rectifier-filter capacitor for AC to DC conversion that draws AC current in short duration peaks at sinewave voltage peaks.

 

[SeaGal]

Is there a reason why are you limiting export to grid?

 

[cajocars]

Is there a reason why are you limiting export to grid?

I don’t have solar; only a battery to cheaply store energy overnight.

 

[fromport]

I noticed that there are a couple of appliances that cause some energy to be exported when in use: one is a Dyson Supersonic Hairdryer and another is a bread maker (it happens when it’s mixing).
What’s the reason?

In particular the hair dryer:
Does it do that when on full power or only on limited/half power ?

 

[cajocars]

In particular the hair dryer:
Does it do that when on full power or only on limited/half power ?

It does it on all power levels, but I just noticed that 50% of the times it exports (let’s say 150W), the other 50% it imports those 150W (instead of hovering around 10W)

 

[fromport]

It does it on all power levels, but I just noticed that 50% of the times it exports (let’s say 150W), the other 50% it imports those 150W (instead of hovering around 10W)

I have seen heat guns regulate the power by putting a diode in series with the heating element that would use only either upper or lower side of the sine wave of the power. A lot of off grid inverters don't like that.

See

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Hair Dryer vs. Inverter mystery

When running a hair dryer my inverter makes this crazy resonating sound. It only happens with the hair dryer and it only happens when the hair dryer is on the low setting. No other loads i've tested, regardless of wattage, cause the inverter to make this sound. The inverter has a transformer...

diysolarforum.com

But at full speed, i would imagine no phase cutting would be present and it shouldn't feed back at that point.