Electrical Output Curve - Where ?

[VF1000R]

Anyone seen a power output curve for the ST ? Alternator output that is.

Coming off the Sabre , I used to run into the problem of having to keep the engine above 3000 to maintain sufficient output.

The Sabre only had .35kW at 5000rpm. ,, after finding out that the output dropped to about .2kW below 3000 , It became nessary to watch the load. I fried one Stator before I learned :mad:

I see the ST has .66kW at 5000rpm (I think), so kinda looking for that "power curve" if anyone has access to it.

Think about , Farkle Lights (90 to 150 watts), Farkle radio ( 50 to 75 watts), Gps - maybe another 50, Autocomm - 10 to 50.
Addem up and you get my drift. OVERLOAD :eek:

Lugging the engine around at 3000r's , may not be a good thing , but cruisng down the road at 50 in 5th is right there, not many folkas are gonna drop to 4th just to keep the r's up.

And Why is my MPG stuck on 36 ???? after all I got a whole 250 miles on the bike, It's broke in ain't it :rolleyes:

[Txrebel]

My bike started at about 38 MPG AVG indicated by the computer, after 3000 miles it now shows 42 MPG AVG. Of course this is actually a little low compared to the true mileage of 45 MPG when I do the calculation the old fashioned way.

I have no idea on the Alternator output.

Rebel :biker:

[NormanPCN]

I see the ST has .66kW at 5000rpm (I think), so kinda looking for that "power curve" if anyone has access to it.


Actually the specs say 740W at 5000rpm. Bike bike is typically quated as having a 660W alternator. I have speculated that the 660 figure is what you get at typical highway speeds. 5000 in 5th is really moving.

[karaszp]

Coming from the Sabre you are comparing apples and oranges. The Sabre has a permanent magnet alternator which always produces maximum output at a given RPM and voltage is regulated by dumping excess output to ground. The ST's alternator uses an electromagnet and the voltage is regulated by governing the excitation current to the magnet, that is, varying the flux density of the magnetic field. The output can be kept constant at lower RPMs by increasing the excitation current to the electromagnet thereby increasing its strength. These alternators can maintain a pretty constant output over a much wider RPM range than the permanent magnet alternator of the Sabre. At some point, however, the RPMs may get so low that the alternator can't keep up with demand and at that point the battery will have to pick up the slack. But it won't happen often.

Pete

[VF1000R]

Dang Karaszp, I didn't catch that.

And just how did you know what type of alternator it has ? :)

Good catch and explain. ! :bow1:

Maybe I need to go buy that Shop manual after all.

[karaszp]

Sorry, I didn't see your reply... I was gone since Thursday to wrestle with the Dragon. Now I have ridden it in the rain; at least there wasn't much traffic in either directions.

About the alternator... as you can see from the signature, I too have a V65 Sabre and on the SABMAG (Sabre-Magna) list the alternator problems of Sabres and Magnas have been laid bare a long time ago. There is also a wiring diagram in the shop manual for the Sabre. Same for the ST. It also helps to know that permanent magnet alternators are limited to around 300-400 watts maximum because the strength of a permanent magnet is limited by size and other considerations plus the oil bath needed to keep the stator from burning out when the voltage regulator dumps the load to ground.

I hope all this doesn't sound greek to you but to understand wiring diagrams you almost have to be some kind of a geek. Chapter 19 of the ST1300 Service manual has it laid out pretty well.

I hope this helps.

Pete