I need a 5000w 120v single phase isolation transformer. Any recommendations?

[SteveDeFacto]

I currently have a 2000w Victron isolation transformer and it works magnificently when charging my Quattro-II from a 15a 120v gfci outlet.

However, I need one for my 5000w generator as my Quattro-II keeps causing the contactor to open. I see Victron has a 3600w 120/240v model and a 7000w 230v-ONLY model.

I need the generator to be running near peak output to avoid wet-stacking. Can I run 2 Victron isolation transformers in parallel? Or perhaps someone knows of a reputable non-victron isolation transformer that can handle 5000w at 120v?

 

[Hedges]

Fixed or mobile?

Second hand utility transformers could be used if size and weight aren't a concern.
They may work OK at rated voltage when fed by a generator. When fed by an inverter, I find they draw excessive no-load current.

If you put 120V into 240V primary windings, or 240V into 480V primary windings, it will draw much lower no-load current (closer to ideal transformer). Output voltage will also be 1/2 of nameplate voltage, and power handling will be 1/2.

So a 10kVA or larger 240/480V to 120/240V transformer should work. Like this, but try to find locally to save shipping.

EMERSON SOLA HD 10KVA TRANSFORMER 240/480V 120/240V 1PH 3R 1YEAR WARRANTY | eBay

International Sales.

www.ebay.com

 

[SteveDeFacto]

Fixed or mobile?

Second hand utility transformers could be used if size and weight aren't a concern.
They may work OK at rated voltage when fed by a generator. When fed by an inverter, I find they draw excessive no-load current.

If you put 120V into 240V primary windings, or 240V into 480V primary windings, it will draw much lower no-load current (closer to ideal transformer). Output voltage will also be 1/2 of nameplate voltage, and power handling will be 1/2.

So a 10kVA or larger 240/480V to 120/240V transformer should work. Like this, but try to find locally to save shipping.

EMERSON SOLA HD 10KVA TRANSFORMER 240/480V 120/240V 1PH 3R 1YEAR WARRANTY | eBay

International Sales.

www.ebay.com

Oh really? I didn't know that would work. The generator is actually an mep-802a on its trailer. I could just mount the massive transformer on the trailer.

 

[Hedges]

The generator may not object to driving inductive loads, so driving primary windings at rated voltage may be OK.

I've seen transformers overload some inverters (UPS), so I like to run at half rated voltage.
Also, driving primary rather than back-driving secondary is much preferred.

transformer excitation current - isolation transformer used as auto-transformer

So you think you can backfeed a transformer secondary, either as step-up or as auto-transformer? Turns out these things aren't so ideal and reversible as one might expect. It isn't just the greater inrush (primary is often wound outside secondary to reduce inrush current), but also idle current...

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