How Does the Regulator on a Wind Genreator work to slow the speed of rotation?

[Mark Turner]

Marlec will themselves answer your questions.

And this is what they said:

1) How does the regulator slow the generator?
This is by PWM ( pulse width modulation ). In a nutshell as battery volts rise above a trigger level the regulator issues a pulsed signal to short circuit the Windcharger output. As battery volts continue to rise the pulses get longer until at a maximum battery volts they are united as a full short circuit. At this point the turbine is unable to rotate faster than an "idle" speed.

2) Is it bad for the generator to be left switched off for a couple of weeks? (The manual says not to tie it off for extended periods)
If the regulator is switched off then a full short circuit is applied to the Windcharger and the turbine is stalled and is unable to rotate faster than an "idle" speed. This is a good thing to do as the turbine will dispel water that may otherwise find its way into bearings should the machine be disabled by tying the turbine up.

3) Is the regulator drawing current from the batteries (which are not being otherwise charged) at a significant rate in slowing down the generator.
Yes the regulator draws only a few milliAmps at all times and this is maximised to no more than about 20mA during regulation. However during regulation ( except for a full short circuit ) some charging of the batteries still occurs.

4) Was I being over cautious in switching it off in the light of the forecast (F8/9)?
Mark you did exactly what I would do. The loss of a few battery Amphours is far less than the loss of a Windcharger ! Very wise indeed. This also could have been a case for tying the turbine off just until the conditions passed. If the stall on a Windcharger is overcome by very strong winds then the generator is in danger of burning out.

As Jerrytug suggested they answered the questions quickly and mostly in terms that I could understand. Great after sales support.

Thanks to everybody for your responses as well.

Mark

 

[Giblets]

Cheers, Mark.

I have printed that out to show my owner who asked exactly the same questions only the other day.

 

[jerrytug]

Thanks for posting the answers from Marlec, Mark, very informative.

 

[pampas]

"Actually, if it was shorted the generator would be producing no power, as there would be no volts. In practice there will be a small voltage across the output, but the power produced will still be very low"

Any generator/alt running about its rated working revs if shorted out will into overload if there is insufficient power to drive that load it will slowdown or stop. you are correct you will not see any voltage beyond the short. That is what I was taught at night school many years ago.

 

[Storyline]

Another vote for great after sales service from Marlec, you always seem to be able to quickly get through to someone who knows what he is talking about.

 

[10oxometer]

I try to sail about twice a month and would like the batteries charging up while away does this mean there is a risk of damage to the generator if left unattended in unexpected high winds?

 

[GrahamM376]

I try to sail about twice a month and would like the batteries charging up while away does this mean there is a risk of damage to the generator if left unattended in unexpected high winds?

A fiend's Aerogen 4 shook itself to bits in Holyhead harbour. When it was returned it to LVM via Cleghorn Waring under warranty, they rejected FOC repairs saying it should be tied off if left unattended when high winds may occur. Sort of defeats the object of having one in some ways. When N Wales based, we just had one 25w solar panel which gave us full charge during the week for when we arrived on a Friday evening. The Aerogen was tied off whilst unattended.

I have seen two other 3 blade wind gennys lose blades in high winds (one causing damage when a blade hit an adjacent boat in the yard) so it's not just Aerogens.

 

[Storyline]

I try to sail about twice a month and would like the batteries charging up while away does this mean there is a risk of damage to the generator if left unattended in unexpected high winds?

The hrdx we have attached to our 913 burnt out during an extremely bad gale a couple of years ago - returned it to Marlec for repair and they said it was the first time they had seen that problem. No damage to the generator though. During the winter we attach a piece of Dyneema to provide additional bracing to the pole it sits on.