Hi guys,

I have a largish toroid I picked up at auction that comes from an Eguana 5kW inverter.

A Canadian company that was building inverters and lithium battery systems in Adelaide, but closed up a while ago.

I understand they were 48V systems.

Anyway there appears to be one secondary winding and four separate primary windings.

With 240VAC applied to the secondary, each primary winding is at 21.58V.

I wound 8 turns and with 240 applied again, the 8 turn winding shows 11.47V

ie. 1.43375 V/T

With other guess work and manipulation, I came up with 167T for the sec and 15T for the primary. Does that sound right? Thanks.

The toroid to the right is a 3kW Aerosharp toroid, so the Eguana one is markedly bigger  ...  and weighs a hefty 32kg.

If you want to double check increase your 8 turn winding to the calculated 15 turns.
It should then read the same voltage as the original primaries.

Thanks Phil, great idea. I never thought of that.

I had been aiming to get 10 turns on there but the wire I chose wasn't long enough. But now we suspect the primary has 15 turns, it should be well worth the effort to wind some more. Thanks again.

Okay, so I wound on 15 turns and get the exact same voltage as the other primary windings  ...  so 15 turns it is.

In thinking about the four primary windings, I decided to pull apart the inverter that it belongs to  ...  and there are four separate bridges (of 16 fets), each driving one winding. Each bridge has two Infineon 2ED21844S06J half-bridge gate drivers.

The auction also had a huge bin of chokes  ...  which I suspect were also used in these systems  ...  but I didn't score any of them. It might have been worth trying to make one work  ...  but without any info on firing it up, I've put it in the too hard basket.

I was impressed with the DC connection terminals. Really substantial boss, thread and nut  ...  and the base has multiple pins that go through a matrix of holes in the board and are soldered in. Looks really solid to me.