Mark Burton a crit :
>
>Fred kindly supplied me with a copy of the schematic.
>
>It looks like a shunt regulator to me.
>
>It makes more sense if the two transistors marked tp154e are actually N channel
MOSFETs with body diodes incorporated (or do some SCRs have a reverse conduction
mode?) Otherwise, the circuit is missing the two diodes needed to connect
the -ve side of the generator coil to ground. If the above is true, the
dissipation
at high load curents is simply the voltage drop across the body diodes
+ the voltage drop across the other two diodes (mr2510) times the load current.
>
>Google doesn't return any useful hits for tp154e.
>
>Bit worried about the two resistors marked 47 because as soon as the input goes
+ve the transistor/SCR/MOSFET would turn on and immediately short out the coil.
Can't believe that's right!
>
>If the above is true, my original point about the external load of the battery
solenoid reducing the dissipation in the regulator is also true in the situation
where the total current drawn from the regulator is sufficiently low to allow
the voltage to rise to the point where the shunt transistors turn on.
>
>
>
Hi all,
Just added some thermal data on the rectifier page
(http://contrails.free.fr/elec_ducati_en.php).
As soon as we have some time, we'll craft something more elaborate. This
little research work is now two years old, and we'll have to delve into
old files and reports.
Would the schematic you're talking about be the preliminary diagram I
published two years ago ? Easy to tell, as it has some French terms
("valeur") and question marks in it.
If it is the case, the TP154E, wrongly depicted as transistors, are
actually thyristors, IIRC.
They are proprietary component, and cannot be found in any public
catalog. My buddy Jrme had to run them on a bench to determine their
specs.
What really matters to homebuilders :
- On must use reasonable loads (10-12 amps continuous)
- Some means of cooling will improve reliability
- The regulator will shut down if the sense wire is disconnected, and
needs sufficient voltage to start to life.
Regards,
Gilles Thesee
Grenoble, France
http://contrails.free.fr
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