disappointing DC conversion...

Anything related to Lambrettas... ask tech questions, post helpful info, or just read and learn.
firekdp
registered user
Posts: 706
Joined: Wed Jan 07, 2009 12:02 pm
Contact:

cezeta wrote:its worth checking this out as i was under the impression that a generator is rated at its potential wattage rather than what is being generated all of the time. ie if no load is present then it is not putting any load on the engine but as soon as an electrical load is applied then the engine is put under load to provide the power.......something to do with apposing magnetic fields from the coils which only exist with a load present v the magnets on the flywheel...... :| ooh...distant memory, i could be wrong.

you can sometime hear this in your car when you flick the lights on or air con for that matter as the same applies. a mate of mine is trying the same thing, he is not a forum user so if he goes for the taffy kit i will report back. worth keeping on the back burner incase you are not happy with the outcome of what you are doing ;)
An alternator has an armature fed with current via slip rings to produce the magnetic field. The regulator on this system is a transistor which switches the current to the armature on and off. If the voltage rises above above 14v the the transistor will switch off the armature current and the field will collapse and so will the voltage. So the alternator will only produce power when needed.
Because a stator has permanent magnets the power will always be produced and the only way to keep the voltage stable is to dump the power not being used. So excess wattage must be used by the regulator and is why the reg has a wattage rating (the amount it can dump)
firekdp
registered user
Posts: 706
Joined: Wed Jan 07, 2009 12:02 pm
Contact:

sean brady scooters wrote:I,m no electrical expert by any means but surely ,all this extra electrical power you are all hoping and expecting for, produced by a small 60,s designed scooter is just not really going to happen is it...?
and if it was some how possible you would end up with a 250cc that produced less power than say a 175...... :D
simply cos a big part of its power would be sapped to go to producing electrical power
Which is why it is best to go for a standard type stator and use a decent battery. Instead of dumping unused power use some of it to charge the battery. Then when the stator is overloaded the battery will fill in for it. This uses power produced more efficiently. Even the original 60's conversion was apparently good enough to run lights and one spot and keep the battery charged.
User avatar
sean brady scooters
Dealer
Posts: 2040
Joined: Mon Jan 05, 2009 12:09 pm
Location: Ripon, North Yorkshire
Contact:

please show me some other machines out there that can possibly power three headlights from a two stroke 200cc motor
and tell me how they do it... :D
and yet produce good power
Sean Brady Scooters - 01765 690 698
User avatar
byron
registered user
Posts: 1226
Joined: Wed Jan 07, 2009 11:45 am
Main scooter: Li Special; scarred,but sound
Location: norwich
Contact:

firekdp wrote:Measure the voltage across the 2 yellows disconnected from the reg/rec and then measure whilst connected to it. The cap on monty's system is masking a problem on his set-up in the same way that the battery is on yours.
thanks. I'll try that tomorrow.
I have got another couple of Wassel units to fit to other scooters, so can swap that out if the test points to the problem being there... And some other stators too...
firekdp
registered user
Posts: 706
Joined: Wed Jan 07, 2009 12:02 pm
Contact:

Your wiring, if like your diagram, is spot on and the lights would be running off the stator if the battery was flat but the reg/rec should be putting out around 13v+. Either the stator or the podtronics looks to be the problem, my money is on the latter. The one thing I would change is the position of the fuse as if you have a problem on one circuit the fuse will blow and leave you with no lights. Move it so that if it blows only the battery is disconnected leaving the reg/rec output still connected to the loom wires.
User avatar
byron
registered user
Posts: 1226
Joined: Wed Jan 07, 2009 11:45 am
Main scooter: Li Special; scarred,but sound
Location: norwich
Contact:

firekdp wrote:Your wiring, if like your diagram, is spot on and the lights would be running off the stator if the battery was flat but the reg/rec should be putting out around 13v+. Either the stator or the podtronics looks to be the problem, my money is on the latter. The one thing I would change is the position of the fuse as if you have a problem on one circuit the fuse will blow and leave you with no lights. Move it so that if it blows only the battery is disconnected leaving the reg/rec output still connected to the loom wires.
cool. good to hear my wiring is ok.
and good tip about the fuse, so putting it on the negative side of the battery would solve that one ?
firekdp
registered user
Posts: 706
Joined: Wed Jan 07, 2009 12:02 pm
Contact:

byron wrote: and good tip about the fuse, so putting it on the negative side of the battery would solve that one ?
Yes.
User avatar
byron
registered user
Posts: 1226
Joined: Wed Jan 07, 2009 11:45 am
Main scooter: Li Special; scarred,but sound
Location: norwich
Contact:

so measuring the AC on the two yellow leads, disconnected to the rectifier is giving around 20v at tickover, and in the 20s & 30s and I even saw 4o-something with some revs... so, even allowing for the half wave factor, that seems like a good supply [in volts at least] from the stator....
Then plugging the yellow leads into the rectifier unit, the reading [still on the yellow wires] dropped to 3-4v AC.
so the rectifier unit is the weak one here....
tried another Wassel unit, same results.

can anyone with the same setup take the same measurements ? and also the output on the red wire [with the battery disconnected]

now got an electrex generic rectifier to try, along with a few others borrowed from mark, chris sadd and goldeneye's donations [received today, cheers mate]
hope to try these later today...
cezeta
registered user
Posts: 1104
Joined: Wed Jan 14, 2009 10:40 pm
Location: Windsor UK
Contact:

firekdp wrote:
cezeta wrote:its worth checking this out as i was under the impression that a generator is rated at its potential wattage rather than what is being generated all of the time. ie if no load is present then it is not putting any load on the engine but as soon as an electrical load is applied then the engine is put under load to provide the power.......something to do with apposing magnetic fields from the coils which only exist with a load present v the magnets on the flywheel...... :| ooh...distant memory, i could be wrong.

you can sometime hear this in your car when you flick the lights on or air con for that matter as the same applies. a mate of mine is trying the same thing, he is not a forum user so if he goes for the taffy kit i will report back. worth keeping on the back burner incase you are not happy with the outcome of what you are doing ;)
An alternator has an armature fed with current via slip rings to produce the magnetic field. The regulator on this system is a transistor which switches the current to the armature on and off. If the voltage rises above above 14v the the transistor will switch off the armature current and the field will collapse and so will the voltage. So the alternator will only produce power when needed.
Because a stator has permanent magnets the power will always be produced and the only way to keep the voltage stable is to dump the power not being used. So excess wattage must be used by the regulator and is why the reg has a wattage rating (the amount it can dump)

thanks for the explanation, we always end up with the naff end of the stick :roll: fortunatly i dont have a need for the extra wattage but if you are going to have those lamps bolted on then its worth getting them to work. i ve been caught in the swiss alps in the rain in the dark and would have loved a set of those lamps. there is led technology bulbs on the way so matbe these will help too.
martinr
registered user
Posts: 129
Joined: Wed Feb 04, 2009 11:06 pm
Contact:

been reading this posting with interest the gp project im doing at the moment is having a 12vdc digital speedo/fuel gauge plus digital rev counter/temp gauge and four led indicators/led rear light. im going to use a varitronic ignition and have a battery. ive got another scoot with a varitronic on it i tested the voltage coming out of the regulator today that keeps the battery charged it was reading 5 vdc at low revs and 7 vdc at higher revs. now heres the question can i run all that direct from the battery and let the stator recharge it. while running headlight/horn on AC or should i go full DC. has anybody got a list of parts i need and complete wireing diagram to go full DC
Post Reply Previous topicNext topic
  • Information
  • Who is online

    Users browsing this forum: Google [Bot] and 1 guest