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Just finished installing the Victron Multiplus 3000 (12v).
Only power source connected are the batteries. (so no charging or shore power or solar yet).
When I turn on the unit, I hear a light hum (which I think is expected).
When I turn on the heat gun at low setting (500-600W) .. I suddenly hear a really loud humming/noise.
Funny thing is, when i change to high setting (1200W) .. the noise goes away!!
Driving me crazy!!
Any help is greatly appreciated!
Thanks,
Sush
It's possible the heat gun uses a diode to make the low power setting. This means the current waveform mostly exists on one half of the cycle when the heat gun is on low. This drives inverters nuts.
I will do more testing tomorrow! Hopefully this is the reason. What is the best way to test high output? I was thinking a space heater or hair dryer.. would they still cause the noise?
thanks!!
sush
Kevin is correct. if a space heater or hair dryer works differently you'll have to test, using a diode is the cheapest way so it might be used.
Is there any risk of damage or additional wear on the inverter in this scenario? I'm experiencing the same issue with a milk bottle modulator at Lower power settings.
As mentioned, diodes are often used on some appliances as a way to provide a half or lower power setting.
The noise is coming from the large toroidial transformer that is mostly used in Victron inverters.
For short term use, it is probably not an issue, but I would not run an inverter under such situations for longer term use. Te noise is physical vibration in the transformer and depending on inverter construction, it may lead to fatigue in solder joints on the PCB. The MOSFETs that drive the transformer would also be put under extra stress since the sine wave is being chopped by either diodes or TRIACs in the load device.
Same exact behavior on my 24/3000/70 with heat gun on low (buzzing from inverter) and heat gun on high (quiet).
Clean sine wave is the easiest load for inverter's transistor.
When diode or triac starts to cut that sine wave to lower the power, transistor gets hotter because the fast changes in the current flow to which it has to react by switching on and off.
As they get hotter, fan needs to cool them and fan is quite noisy.
