Ampinvt huge DC amp swings?

[johntaves]

I have an Ampinvt 6000W 24V split phase inverter.

The DC Amps are swinging wildly when the inverter is on. Below is a screen shot where the inverter is running an induction cooktop and an oven. The AC amps were 12 and 16 on the 2 different phases, so total 3360W, and therefore 134A at 25V.

The black line is the DC amps sampled every 2 seconds. It is swinging from zero to at least 300A. The upper left corner of the image shows it saw 300A.

Ampinvt is trying to tell me that this is normal. Will the DC amps be relatively stable with a steady AC load on the inverter? Or is Ampinvt correct to say that the DC amps will oscillate like this?

 

[MisterSandals]

Below is a screen shot where the inverter is running an induction cooktop and an oven.

Are you sure these don't cycle on and off once it gets up to temp?

 

[johntaves]

The amps are oscillating when charging and when there's only the clock load. I put a digital shunt in line and it's oscillating very fast. I'll bet it's at 60hz. I'll confirm that frequency.

The web page is displaying every 2 sec so it's not capturing the full oscillations

 

[johntaves]

I took 2000 samples and pumped them into a discreet Fourier that had a spike at 34 samples, which means 166ms. That is 6hz, which is suspiciously spot on 10x of 60hz (maybe sampling at 4.8ms was too slow to properly pick up the dominant 60hz).

Shouldn't the inverter have some capacitance that effectively eliminates the oscillation on the input side (DC) that is the output (AC)?

 

[johntaves]

To answer my own question:

Yes, inverters generally have big capacitors on the input (DC) side that should smooth out the current. There should not be any significant amplitude of a 60hz signal on the DC side.

My inverter must have some failed parts.