power flickering from small 12vdc -> 120vac inverter attached to EV

[Whitenuckler]

You can always make changes later after some testing. I have never seen anything in series with a transformer winding. Inrush is considered normal, as log as nothing is connected to the output until it stabilizes, it won't even know about it.
Is that because the inverter could trip out?

 

[RustyShackleford]

You can always make changes later after some testing. I have never seen anything in series with a transformer winding. Inrush is considered normal, as log as nothing is connected to the output until it stabilizes, it won't even know about it.
Is that because the inverter could trip out?

Testing earlier today, just plugging the transformer into a 20amp outlet, the breaker (in the main load center) tripped a couple times (but less than half the time probably). I can only imagine and inverter would be worse; although I did briefly run the pump (thru the transformer) from my 1000watt EV-connected inverter (I can't recall the sequence in which I brought things online).

My McIntosh tube amps actually do have thermistors on the power to the primary of their power transformers.

 

[Whitenuckler]

Testing earlier today, just plugging the transformer into a 20amp outlet, the breaker (in the main load center) tripped a couple times (but less than half the time probably). I can only imagine and inverter would be worse; although I did briefly run the pump (thru the transformer) from my 1000watt EV-connected inverter (I can't recall the sequence in which I brought things online).

My McIntosh tube amps actually do have thermistors on the power to the primary of their power transformers.

I'd test it with the inverter, as that is going to be the normal supply. The inverter output voltage is not as firm as your panel.

 

[RustyShackleford]

I'd test it with the inverter, as that is going to be the normal supply. The inverter output voltage is not as firm as your panel.

Clearly. But the fact I got it to run at all, with a 1000 watt inverter actually putting out 12 amps, makes me comfortable. I haven't acquired the Ecoflow yet, nor thermistor for the transformer input.

 

[RustyShackleford]

I cheated on you guys and asked about this at an EE forum, and some guy clued me in to how to run the transformer as an autotransformer, and therefore get the outputs to look like split-phase 240vac WITHOUT adding any components, just a connection between the hot input to the primary and one of the secondary outputs. Explained thus:

I basically turned your isolated transformer into an autoformer, where the lower primary (non-dotted) terminal is equivalent to the nonexistent center tap on the secondary. Since that lower primary terminal is connected to neutral, it's the same as connecting a center tap on the secondary to neutral. The result is that the upper secondary terminal is 120 V relative to neutral/ground, and because of the selected primary-secondary phasing, the lower secondary terminal is also 120 V relative to neutral/ground, and 240 V relative to the upper terminal. The common-mode output voltage is at most a few volts resulting from different primary and secondary currents and impedances.

So my design now looks like:

 

[RustyShackleford]

 

[Whitenuckler]

View attachment 347222

Looks good. The enclosure is the perfect size. Check the volts to ground on both the 240 terminals after you power it up. That is one big chunk of copper and steel.

 

[RustyShackleford]

Looks good. The enclosure is the perfect size. Check the volts to ground on both the 240 terminals after you power it up. That is one big chunk of copper and steel.

I think I will put a VAC meter as you suggested. I'm a little worried that DJI power station only does 110vac and I need to keep the pump voltage abve 200. Based the tests I reported in post #65 above, with 122vac from an un-loaded circuit, when the pump came on that dropped to 119vac and the pump voltage to 228vac. So I should be ok.

 

[RustyShackleford]

In fact, I just measured 119vac with the DJI 1000 V2 outputting 2700 watts of resistive load.