Introduction and Stator removal question

[iansoady]

Best way to reduce the load is to fit a mosfet RR as it limits the load on the stator to just over the actual requirements.

I've never quite understood this as the alternator is a permanent magnet machine therefore surely generates at full whack all the time. Mind you I'm more familiar with Joe Lucas's efforts controlled by Zener diodes......

[oxnsox]

Best way to reduce the load is to fit a mosfet RR as it limits the load on the stator to just over the actual requirements.

I've never quite understood this as the alternator is a permanent magnet machine therefore surely generates at full whack all the time. Mind you I'm more familiar with Joe Lucas's efforts controlled by Zener diodes......

A zener is used to set a voltage where a regular diode simply works like a switch, it's either on or off.
In a simple RR arrangement its on for the same amount of time it's off. (this is how it turns the ac from the stator into dc, but it doesn't control it. )
A mosfet is more like a tap, it can control the amount of on or off time, so it can control the flow (load).

[oxnsox]

Best way to reduce the load is to fit a mosfet RR as it limits the load on the stator to just over the actual requirements.

I've never quite understood this as the alternator is a permanent magnet machine therefore surely generates at full whack all the time. Mind you I'm more familiar with Joe Lucas's efforts controlled by Zener diodes......

A zener is used to set a voltage where a regular diode simply works like a switch, it's either on or off.
In a simple RR arrangement its on for the same amount of time it's off. (this is how it turns the ac from the stator into dc, but it doesn't control it. )
A mosfet is more like a tap, it can control the amount of on or off time, so it can control the flow (load).

[iansoady]

So let me see if I understand it.

In a simple zener controlled system (and I take it that standard reg / rec works in a similar way), any excess voltage is simply allowed to leak to earth via an effective short circuit (hence the substantial heat sinks needed even for Lucas's finest). With the Mosfet arrangement when an excess arises it is controlled by going open circuit for part of the cycle.

Is that right? Or does the mosfet still divert excess to earth but merely in a cleverer way?

This is of course very different to a car alternator where the regulation is achieved by altering the current through the field windings on the rotor rather like the old dynamo system.

[oxnsox]

So let me see if I understand it.

In a simple zener controlled system (and I take it that standard reg / rec works in a similar way), any excess voltage is simply allowed to leak to earth via an effective short circuit (hence the substantial heat sinks needed even for Lucas's finest).

Correct.
(except we're talking about current not voltage)

With the Mosfet arrangement when an excess arises it is controlled by going open circuit for part of the cycle.

Yes
But really we're not talking about the excess we're talking about only taking what we need

Is that right? Or does the mosfet still divert excess to earth but merely in a cleverer way?

This is of course very different to a car alternator where the regulation is achieved by altering the current through the field windings on the rotor rather like the old dynamo system.

A bit different to a dynamo but yes you're essentially correct. Ultimately it's a cost driven solution and a stator on the end of the crank is mechanically simple and cheap. But a car requires a lot more power and at some point it's probably cheaper (and lighter) to go with an alternator which in a bigger vehicle can also have its drive geared up easily.

[SilverTiger]

I'm off on a big Euro trip next week and all these posts about R/R and stators burning out are making me nervous.  I bought a 2006 Tiger in March with 12k miles on it, fitted a voltmeter so I can keep tabs on battery charging.  No problems so far, haven't done Sasquatch fix yet either.  I'm going to fit a mosfet R/R from Electrex World this week, I'm thinking of taking a spare stator just in case. I have noticed that some retailers sell the stator with the connector for the stator cable unfitted  ie in pieces - block plus pins, which would need to be crimped on.  Is this because the wire from the stator needs to be fed through a hole in the case before fitting the connector and pins?  Seems a bit odd to me, every other bike I've had has a detachable grommet in the mating face of the case meaning the wire just pushes in, no worries about connector being fitted.  I would take my stator cover off and check but I've only just fitted crashbars  :lol:    Also, reading some of the (very useful) posts above, am I correct in thinking that by using a mosfet type R/R I may actually be extending the life of my current stator?  Thanks for any input, and apologies to original poster for the hijack  :lol:   Ian.

[Spud]

I did 25k before i had a problem with my bike. Any bike can play as can any car. Ride it enjoy it if it breaks fix it. I'm off to France on the 13th going south to the mountains. I hope to do about 3k in mileage.

I'm doing little checks on the bike and things seem to need replacing, scottoiler feed pipe ect, I think some times a touch of  " if it ain't broke dont fix it" is the best way.

cheers Spud