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temporarily when transferring
between grid and inverting.
may be too low to sustain
certain loads.
DIP switch, or Install a UPS if
possible.
Noise from Transformer/case*
Applying specific loads such as
hair drier
Remove the loads
*The reason for the noise from transformer and/or case
When in inverter mode sometimes the transformer and/or case of the inverter may vibrate and make noise.
If the noise comes from transformer:
According to the characteristics of our inverter, mainly there is one type of load which most likely may cause rattles of transformer.
That is half wave load: A load that uses only half cycle of the power (see figure 1). This tends to cause an imbalance of the magnetic field of the transformer,
reducing its rated working freq from 20KHz to maybe 15KHz (it varies according to different loads). In such a case the frequency of noise falls exactly into the
range (200Hz-20KHz) that human ears can hear.
The most common load of such kind is a hair drier.
If the noise comes from the case:
Normally when loaded with inductive loads, the magnetic field generated by the transformer keeps attracting or releasing the steel case at a specific freq, this
may also cause noise.
Reducing the load power or using an inverter with bigger capacity will normally solve this problem.
The noise will not do any harm to the inverter or the loads.
Figure 1 Half Cycle Load Waveform
5
Warranty
We offer a 1 year limited warranty.
The following cases are not covered under warranty.
1 DC polarity reverse.
The inverter is designed without DC polarity reverse protection. A polarity reverse may severely damage the inverter.
2 Wrong AC wiring
3 Operating in a wet environment.
