Windmill Alternator 3-Phase Rectification Circuit

[Renfro]

I will start by thanking you for taking the time to view my post. I am a new member here so hello everyone!

I have a windmill that has an alternator/generator consisting of a rotor that has 16 permanent magnets and 36 stator windings.

There are 3 bridge rectifiers, each having one AC terminal connected to stator windings with the other AC terminal empty. (This is the confusing part...) and the +/- DC terminals of all three bridge rectifiers are collected in parallel for DC output.

I thought that the bridge rectifier AC input terminals should be connected together in this type of "phase-phase" rectification application. See image below.

This image shows what I expected to see however what I found in the unit didn't have the jumper/connection between the AC terminals of the bridge rectifiers. Each rectifier has one empty AC terminal.

My question is, wouldn't it be better to connect the AC input to the rectifiers as is indicated in the aforementioned schematic? or would this be a mistake? Wouldn't it provide less ripple in the DC output and more power?

 

[Tony Stewart]

>isolating the sheets by coating them individually before stacking will limit the eddy currents thus allowing the device to operate efficiently.

A common fault in core fabrication are dull sheers on cutting the sheets which also exposes the SiC coating. But the shorting should only be on the edges. But SiC coating is also a rust protection which ought to have been done to coat the edges to prevent rust. A Kelvin bridge current source could be done to prove the microohm resistance difference between suspect uncoated transformer steel and edge shorted SiC coated CRGOS. Eddy currents may be detect by odd harmonics. Core saturation from fundamental voltage tend to be 5th harmonic. from my limited experience on MVA transformers.

 

[rjenkinsgb]

If there are significant eddy current losses, I'd expect the stator to warm up significantly even when run with no load?

 

[Renfro]

If there are significant eddy current losses, I'd expect the stator to warm up significantly even when run with no load?

It does get very warm even with ambient 17°F and 20mph winds. I put an IR thermometer at it and was seeing 80 and 90° F temps. Id be reluctant to see how hot it would get on a warm summer day.

 

[Tony Stewart]

If you convert to Celcius, the rise will be the same.

 

[Pommie]

If you convert to Celcius, the rise will be the same.

Or Kelvin or Spaghetti degrees. Or, just go have coffee, the rise will still be the same.

Mike.

 

[rjenkinsgb]

It does get very warm even with ambient 17°F and 20mph winds.

Was that without any load at all??

 

[Pommie]

I tried using a high frequency MOSFET switch and three ferrite inductors to achieve phase correction on a high frequency three phase generator. Failed miserably.

Mike.