Lucas C40 22/25amp Dynamos NEW USE

[blodger]

I have acquired four C40s and got them working at least as motors so presume they will function as they were designed to do. Two 2 bobbin and one three bobbin regs came with them; one two bobbin might be serviceable.

 

In a way this is a continuation of the lawnmower generator thread but specific to C40s

 

I am looking to use the C40s without the reg by putting a 30amp diode in the battery charging line and controlling using the field connection if that is feasible. The resistance between field(F) and battery(D) in one reg seems to be 500 ohms and in the three bobbin there's one of 67ohms and one bigger centre tapped that I have not got out yet to measure.

 

What sort of current does the field circuit run and what resistance range is needed.

 

I understand these dynamos max out at 4,500 rpm but when attached to a Suffolk Punch 98cc engine with one to one gearing will only be doing 3,000 max; Perhaps I will have to gear up?

 

Hopefully, the diode gets around the battery to be charged driving the dynamo as motor; the cut out function of the reg. The voltage regulation side of the old regs seems pretty crude; solenoid cut out but presumably at high revs.

The info on the net infers these dynamos can put out 16.5v clamped to the battery 24v open circuit.

I presume the direction of rotation is not mission critical but for the correct operation of the cooling fan behind the drive pulley?

 

Any information gratefully received

Edited April 26, 2010 by blodger

[Tony Brooks]

I have acquired four C40s and got them working at least as motors so presume they will function as they were designed to do. Two 2 bobbin and one three bobbin regs came with them; one two bobbin might be serviceable.

 

In a way this is a continuation of the lawnmower generator thread but specific to C40s

 

I am looking to use the C40s without the reg by putting a 30amp diode in the battery charging line and controlling using the field connection if that is feasible. The resistance between field(F) and battery(D) in one reg seems to be 500 ohms and in the three bobbin there's one of 67ohms and one bigger centre tapped that I have not got out yet to measure.

 

What sort of current does the field circuit run and what resistance range is needed.

 

I understand these dynamos max out at 4,500 rpm but when attached to a Suffolk Punch 98cc engine with one to one gearing will only be doing 3,000 max; Perhaps I will have to gear up?

 

Hopefully, the diode gets around the battery to be charged driving the dynamo as motor; the cut out function of the reg. The voltage regulation side of the old regs seems pretty crude; solenoid cut out but presumably at high revs.

The info on the net infers these dynamos can put out 16.5v clamped to the battery 24v open circuit.

I presume the direction of rotation is not mission critical but for the correct operation of the cooling fan behind the drive pulley?

 

Any information gratefully received

 

 

I am not going to be much help but if those Resistances were measured across the "resistors" on the bottom of the regulator they will almost certainly not be what you are looking for. I think one is related to spark suppression at the contacts and one gives the minimum output" when the regulator points are open. The resistance you are looking for is not used as such because the regulator is constantly switching the fields in and out of circuit to maintain an "average" field strength to give the required regulated output.

 

The volatge regulator setting for the C40 is open circuit (piece of paper between the cutout points) 16.6 volts with a two bobbin regulator and 15.5 volts with a three bobbin one.

 

My feeling is that you would need a variable resistor and constant attention and I suspect a variable resistor with a sufficient current rating may be expensive. If it were mine I would build the thing up and get it running. Then connect the D terminal to the F and gradually rev the engine until I was sure the engine will drive at 22 amps output. Then lash out £25 on a three bobbin regulator (Vehicle Wiring products 83300).

 

I hope someone can come up with the value you need.

[RLWP]

As it happens, a long time ago I made a generator using a dynamo and a Suffolk Punch lawnmower engine. Cutting a long story short, It only really worked when I swapped the dynamo for an alternator.

 

Richard

[blodger]

I am not going to be much help but if those Resistances were measured across the "resistors" on the bottom of the regulator they will almost certainly not be what you are looking for. I think one is related to spark suppression at the contacts and one gives the minimum output" when the regulator points are open. The resistance you are looking for is not used as such because the regulator is constantly switching the fields in and out of circuit to maintain an "average" field strength to give the required regulated output.

 

The volatge regulator setting for the C40 is open circuit (piece of paper between the cutout points) 16.6 volts with a two bobbin regulator and 15.5 volts with a three bobbin one.

 

My feeling is that you would need a variable resistor and constant attention and I suspect a variable resistor with a sufficient current rating may be expensive. If it were mine I would build the thing up and get it running. Then connect the D terminal to the F and gradually rev the engine until I was sure the engine will drive at 22 amps output. Then lash out £25 on a three bobbin regulator (Vehicle Wiring products 83300).

 

I hope someone can come up with the value you need.

Thanks for that.

The resistor measured was between D & F inside reg.

My experience with Suffolk Punch & Alternators is that they are OK for upto 15amps before stalling so I was looking to similar from a dynamo

 

As it happens, a long time ago I made a generator using a dynamo and a Suffolk Punch lawnmower engine. Cutting a long story short, It only really worked when I swapped the dynamo for an alternator.

 

Richard

Yes, the Suffolk Punch is a bit small and I have a couple working with alts (One I have set up for equalising charging) that would stall if the batteries are well discharged so I was looking to the smaller capacity dynamos. I am trying to make one up that works no probs to give to a liveaboard with an SR2 that he rarely runs with consequent damage to batts that he also does not musch use but, expecting them to stay OK!

I won the dynamos on EBay for a pound and my travel costs to experiment with. Little lost if I cannot use them; I can always try re-selling them!

[Gibbo]

Tony is right. You really don't want to try to do this with a resistor.

 

The resistor in the reg sets the minimum current that the field is fed with when the reg switches off. To switch the field on it connects it directly to the battery (well actually the dynamo output) and the only thing limiting the current is the small series resistance of the solenoid in the reg.

 

Typical field current is 3 amps or so.

 

To try to regulate it with a variable resistor would result in a wildly variable output that literally bounces all over the place and a resistor the size of a half housebrick. I've seen it done with small variable resistors, but the installer can never understand why he has to replace the resistor every few days. I can.

 

Just use a proper reg.

[blodger]

Tony is right. You really don't want to try to do this with a resistor.

 

The resistor in the reg sets the minimum current that the field is fed with when the reg switches off. To switch the field on it connects it directly to the battery (well actually the dynamo output) and the only thing limiting the current is the small series resistance of the solenoid in the reg.

 

Typical field current is 3 amps or so.

 

To try to regulate it with a variable resistor would result in a wildly variable output that literally bounces all over the place and a resistor the size of a half housebrick. I've seen it done with small variable resistors, but the installer can never understand why he has to replace the resistor every few days. I can.

 

Just use a proper reg.

I'll try the reg I have and keep an eye out for an EBay cheapie; Have got to get another Suffolk Punch running first.

My understanding so far is that without a reg its difficult to do anything other than field connected or off ie max volt & current or nowt. So switching from off to full on will propably result in stalling the little engine but seems to me that that is likely to happen anyway with a matched reg?

 

I have found that with 70amp alts I can limit field current at start up by switching out, using a double (treble with excite switch-off) two way switches, 22 ohm resistors to obviate stalling and charging at the max the engine can deliver especially from cold. I was hoping by experiment to do similar with the dynamo.

 

Googling I have come across the 'Rainbow Trading DIY Plans & Guides Publications', rainbowtradingpost.co.uk, they do lots of 3.00 roughly guides on lots of electrical gizmos. One listed (JEPH4) is 'Portable Battery Charging Generator 12v Output' with two lawnmower/dynamo designs voltage regulated and non-regulated. I think I'll get it.

 

One that appeals is (ALT2SEG) 'Reciprocating Steam Engine Plans' - How to build a steam engine capable of powering a 1kw alternator using a flash type boiler best suited to wood burning. Single cylinder, double acting engine able to be made by the average handyman with reasonable skills. It says 'A good plan for producing power if you have a readily available source of wood. I think I'll stick to the B&S and Suffolk Punch for now!

[Rojja]

I have acquired four C40s and got them working at least as motors so presume they will function as they were designed to do. Two 2 bobbin and one three bobbin regs came with them; one two bobbin might be serviceable.

 

In a way this is a continuation of the lawnmower generator thread but specific to C40s

 

I am looking to use the C40s without the reg by putting a 30amp diode in the battery charging line and controlling using the field connection if that is feasible. The resistance between field(F) and battery(D) in one reg seems to be 500 ohms and in the three bobbin there's one of 67ohms and one bigger centre tapped that I have not got out yet to measure.

 

The 'centre tapped resistor is (from memory) 150ohm overall but the outer ends are connected giving 75 ohm. This resistor is permanantly connected between D & F to quench the considerable back emf when the voltage or the current regulator contacts open.

If you're measuring 500 ohms between D&F on the reg I think something is awry.

 

What sort of current does the field circuit run and what resistance range is needed.

The field resistance is ~6 ohms increasing to 7 when the dynamo is hot. With 12-15 volts it won't be much above 2 Amps.

I understand these dynamos max out at 4,500 rpm but when attached to a Suffolk Punch 98cc engine with one to one gearing will only be doing 3,000 max; Perhaps I will have to gear up?

With a SIF engine you won't want to do that.

The dynamo will stuff 25 amps into a discharged good battery (12 ish volts) and will be held back because it won't be reaching it's maximum torque (rpm) at this load.

Hopefully, the diode gets around the battery to be charged driving the dynamo as motor; the cut out function of the reg. The voltage regulation side of the old regs seems pretty crude; solenoid cut out but presumably at high revs.

The info on the net infers these dynamos can put out 16.5v clamped to the battery 24v open circuit.

Sorry, I don't quite follow the above.

Yes, a diode will prevent the dynamo motoring, however a a decent relay across the diode will (as with the one I made) allow the dynamo to auto start the SIF

I presume the direction of rotation is not mission critical but for the correct operation of the cooling fan behind the drive pulley?

No! Been there. These dynamos will only produce useful output turning clockwise looking at the drive end. Rotating then anticlock they will only produce about 2-3volts with D&F connected at 6000rpm.

Any information gratefully received

The one I cobbled together about 20 years ago and is still going strong has a three coil regulator which can be overidden by a switch. The engine is overloaded when this was done so I've added a 4R7 resistor to the field which allows the poor little engine to get on its cam!

 

By the way the generators fierld current max's out at 2 amps (pushing 27 amps into a flat, good, 220 ah battey) but beware, always keep at least 100ohms between the field-F and the armature -D as the open circuit back emf if opened without will surprise!

 

There's some (big) pic's of my bodge at

 

http://www.rgee.co.uk/temp/SIFgen/1.JPG

 

for more, if you're brave

 

change the last bit to 2.JPG to 6.JPG

 

Sorry to go on so much,

Roj.

[blodger]

The 'centre tapped resistor is (from memory) 150ohm overall but the outer ends are connected giving 75 ohm. This resistor is permanantly connected between D & F to quench the considerable back emf when the voltage or the current regulator contacts open.

If you're measuring 500 ohms between D&F on the reg I think something is awry.

 

 

The field resistance is ~6 ohms increasing to 7 when the dynamo is hot. With 12-15 volts it won't be much above 2 Amps.

 

With a SIF engine you won't want to do that.

The dynamo will stuff 25 amps into a discharged good battery (12 ish volts) and will be held back because it won't be reaching it's maximum torque (rpm) at this load.

 

Sorry, I don't quite follow the above.

Yes, a diode will prevent the dynamo motoring, however a a decent relay across the diode will (as with the one I made) allow the dynamo to auto start the SIF

 

No! Been there. These dynamos will only produce useful output turning clockwise looking at the drive end. Rotating then anticlock they will only produce about 2-3volts with D&F connected at 6000rpm.

 

The one I cobbled together about 20 years ago and is still going strong has a three coil regulator which can be overidden by a switch. The engine is overloaded when this was done so I've added a 4R7 resistor to the field which allows the poor little engine to get on its cam!

 

By the way the generators fierld current max's out at 2 amps (pushing 27 amps into a flat, good, 220 ah battey) but beware, always keep at least 100ohms between the field-F and the armature -D as the open circuit back emf if opened without will surprise!

 

There's some (big) pic's of my bodge at

 

http://www.rgee.co.uk/temp/SIFgen/1.JPG

 

for more, if you're brave

 

change the last bit to 2.JPG to 6.JPG

 

Sorry to go on so much,

Roj.

That's all useful stuff and great pics and has saved me some experimentation which would have had its shortcomings.

 

The direction of rotation issue means direct coupling makes sense and with the ability to start by dynamo a plus; Relay across any diode or reg cut out to function.

 

I had thought that rpm would be too low to direct couple but yours works OK but with the caution that switching out the reg stalls eng. I also picked up that using pulleys to drive dynamo faster would mean insufficient engine torque probably?

Additional 4R7 resistor is a wire wound 7 ohm resistor to double field resistance and prevent stalling in unregulated mode?

 

You seem to be saying that with the reg there is a 75ohm resistance between D & F and that in experimenting without a reg then there's a need to ensure a 100ohm resistance to quench switching back emfs.

 

I cannot understand why there are not more of these things around from the days of the changeover to alts.

[RLWP]

That's all useful stuff and great pics and has saved me some experimentation which would have had its shortcomings.

 

The direction of rotation issue means direct coupling makes sense and with the ability to start by dynamo a plus; Relay across any diode or reg cut out to function.

 

I had thought that rpm would be too low to direct couple but yours works OK but with the caution that switching out the reg stalls eng. I also picked up that using pulleys to drive dynamo faster would mean insufficient engine torque probably?

Additional 4R7 resistor is a wire wound 7 ohm resistor to double field resistance and prevent stalling in unregulated mode?

 

You seem to be saying that with the reg there is a 75ohm resistance between D & F and that in experimenting without a reg then there's a need to ensure a 100ohm resistance to quench switching back emfs.

 

I cannot understand why there are not more of these things around from the days of the changeover to alts.

 

There were, but the changeover to alternators was in the mid to late 1970's so they've all gone to the scrapyard decades ago.

 

Plenty at autojumbles of course

 

Richard

[WotEver]

Additional 4R7 resistor is a wire wound 7 ohm resistor to double field resistance and prevent stalling in unregulated mode?

No. 4R7 is another way of saying 4.7 Ohms

 

Tony

[blodger]

No. 4R7 is another way of saying 4.7 Ohms

 

Tony

Thanks for that I have found it confusing when looking at EBay offers and it had not dawned on me!

 

 

 

Just use a proper reg.

Ebay has a 'Control Box to replace the RB340' for 6.95 + 3.95 P&P so I am arming myself with one!

 

There were, but the changeover to alternators was in the mid to late 1970's so they've all gone to the scrapyard decades ago.

 

Plenty at autojumbles of course

 

Richard

I recall seeing set ups from time to time but never seen them used in earnest

[Gibbo]

No! Been there. These dynamos will only produce useful output turning clockwise looking at the drive end. Rotating then anticlock they will only produce about 2-3volts with D&F connected at 6000rpm.

 

There's something wrong here. They should work exactly the same in both directions.

[Tony Brooks]

There's something wrong here. They should work exactly the same in both directions.

 

I hate to question Gibbo and I hope he will explain if I am wrong.

 

Aren't the brushes offset from the field pole pieces so they are at the optimum position to maximise the output at charging speed?

 

If they are running the thing in reverse will have the brushes way out of line with the magnetic field and thus lower the output.

 

I have just read (Automobile Electrical Equipment 1958) that the brushes are given to minimise sparking at the commutator.

 

Any way which ever is correct the distortion in the field when running should reduce output if run in reverse.

 

Trying to think back I am sure the C39 & C40 had DOR arrows on the case.

[blodger]

I hate to question Gibbo and I hope he will explain if I am wrong.

 

Aren't the brushes offset from the field pole pieces so they are at the optimum position to maximise the output at charging speed?

 

If they are running the thing in reverse will have the brushes way out of line with the magnetic field and thus lower the output.

 

I have just read (Automobile Electrical Equipment 1958) that the brushes are given to minimise sparking at the commutator.

 

Any way which ever is correct the distortion in the field when running should reduce output if run in reverse.

 

Trying to think back I am sure the C39 & C40 had DOR arrows on the case.

 

 

These C40s do indeed have an arrow etched into the casing for rotation direction but that would be for cooling fan?

[Tony Brooks]

These C40s do indeed have an arrow etched into the casing for rotation direction but that would be for cooling fan?

 

From what I can remember the "blades" on the metal fans are on the radius not at tangents so they should work in either direction. I seem to recall some plastic fans had curved blades which would be directional.

[Gibbo]

I hate to question Gibbo and I hope he will explain if I am wrong.

 

Aren't the brushes offset from the field pole pieces so they are at the optimum position to maximise the output at charging speed?

 

If they are running the thing in reverse will have the brushes way out of line with the magnetic field and thus lower the output.

 

I have just read (Automobile Electrical Equipment 1958) that the brushes are given to minimise sparking at the commutator.

 

Any way which ever is correct the distortion in the field when running should reduce output if run in reverse.

 

Trying to think back I am sure the C39 & C40 had DOR arrows on the case.

 

The magnetic field is identical relative to the rotor whichever direction it is going in.

 

The reason for the offset brushes is purely mechanical. Nothing to do with the magnetic positioning or electrical. It should produce the same power in either direction. The explanation in "Automobile Electrical Equipment 1958" is indeed correct.

 

Edit: Out of interest I've just done some magnetic simulation of a dynamo. The only way the rotation can affect the power generated is if the brushes are not 180 degrees apart on the commutator. If they are 180 degrees apart then the direction of rotation makes no difference whatsoever.

 

Placing the brushes at anything other than 180 degrees always results in a loss of power so no one would ever do that in a dynamo (well I can't think why anyone would want to do it anyway). Indeed, some motors used to have an extra brush mounted at about 100 degrees and switching between the brushes resulted in two different speeds. The most common use for this was old twin speed windscreen wiper motors.

Edited April 28, 2010 by Gibbo

[blodger]

The 'centre tapped resistor is (from memory) 150ohm overall but the outer ends are connected giving 75 ohm. This resistor is permanantly connected between D & F to quench the considerable back emf when the voltage or the current regulator contacts open.

If you're measuring 500 ohms between D&F on the reg I think something is awry.

 

 

The field resistance is ~6 ohms increasing to 7 when the dynamo is hot. With 12-15 volts it won't be much above 2 Amps.

 

With a SIF engine you won't want to do that.

The dynamo will stuff 25 amps into a discharged good battery (12 ish volts) and will be held back because it won't be reaching it's maximum torque (rpm) at this load.

 

Sorry, I don't quite follow the above.

Yes, a diode will prevent the dynamo motoring, however a a decent relay across the diode will (as with the one I made) allow the dynamo to auto start the SIF

 

No! Been there. These dynamos will only produce useful output turning clockwise looking at the drive end. Rotating then anticlock they will only produce about 2-3volts with D&F connected at 6000rpm.

 

The one I cobbled together about 20 years ago and is still going strong has a three coil regulator which can be overidden by a switch. The engine is overloaded when this was done so I've added a 4R7 resistor to the field which allows the poor little engine to get on its cam!

 

By the way the generators fierld current max's out at 2 amps (pushing 27 amps into a flat, good, 220 ah battey) but beware, always keep at least 100ohms between the field-F and the armature -D as the open circuit back emf if opened without will surprise!

 

There's some (big) pic's of my bodge at

 

http://www.rgee.co.uk/temp/SIFgen/1.JPG

 

for more, if you're brave

 

change the last bit to 2.JPG to 6.JPG

 

Sorry to go on so much,

Roj.

I've wasted some time trying to get a Suffolk Punch running from two seized ones I picked up and one I had where the crankshaft bearings were shot. By the time I'd got the valves out they were beyong valve lapping and the 'tool' was too big for the sucker to stick! I persisted but what I have put together only runs for minutes and stops and does not pick up; poor compression due to the valves. Moral seized engines are not easy to strip and rebuild successfully.

 

So built another wood bed and transferred an engine that I had welded a (alternator) pulley to and set up the dynamo opposite using a lawnmower belt. So the gearing is less than 1:1. Put a diode in the line from dynamo to battery connection and made up a switch in the battery to field line with 90 ohms across as suggested.

 

Started engine on pull cord and switched field on and result,it was charging, only a couple of amps at tickover. Increasing speed increased volts from 13.6 to 15.9 and amps to 16. However, this was a collection of redundant batts that are left on a 1/2 amp charger nearly all the time; So only a quick test.

 

Picked up a selection of 4.7 and 2.2 ohm resistors of 50 watt should I find the stalling situation when I try it elsewhere. When I have the time I might try the control boxes that came with them to see if they work

[blodger]

I've wasted some time trying to get a Suffolk Punch running from two seized ones I picked up and one I had where the crankshaft bearings were shot. By the time I'd got the valves out they were beyong valve lapping and the 'tool' was too big for the sucker to stick! I persisted but what I have put together only runs for minutes and stops and does not pick up; poor compression due to the valves. Moral seized engines are not easy to strip and rebuild successfully.

 

I take it back! I had the thought that the engine I took the magneto off with the knacked crankshaft bearings would only run intermittently. I had used a different flywheel with the embedded magnets because of the circumference wear with it acting as a bearing. I have now put on the third flywheel that from measuring has reduced the air gap further; Ran 2nd pull. Still not a lot of compression but it will coke up and improve?

[blodger]

I hate to question Gibbo and I hope he will explain if I am wrong.

 

Aren't the brushes offset from the field pole pieces so they are at the optimum position to maximise the output at charging speed?

 

If they are running the thing in reverse will have the brushes way out of line with the magnetic field and thus lower the output.

 

I have just read (Automobile Electrical Equipment 1958) that the brushes are given to minimise sparking at the commutator.

 

Any way which ever is correct the distortion in the field when running should reduce output if run in reverse.

 

Trying to think back I am sure the C39 & C40 had DOR arrows on the case.

An info booklet arrived recently about Suffolk Engines and Dynamos for 12v battery charging with two versions regulated and unregulated.

 

It does not specify the dynamo model but because the mountings mean it is driven backwards it advises the following mods:-

1. Remove the fan and bend the blades so that they will cool in reverse rotattiom.

2. Remove the rear/cover/brush assembly & unsolder the two wires from the field coils, reverse them and resolder them back onto the tag connector.

 

Of the four C40s I picked up, two had 'tangential' fans and one had one which was 'directional'. The one that had no fan is now on a Zetor tractor using the fan/pulley that was on the failed dynamo. I am having to put a new regulator on that, those I picked up with the dynamos appear demic/worn out but I have not finished experimenting with them yet!

 

Thanks for your, Gibbo's and others contribution

[WotEver]

2. Remove the rear/cover/brush assembly & unsolder the two wires from the field coils, reverse them and resolder them back onto the tag connector.

I recall back in my early days of tinkering with cars that you could 'flash' a dynamo to change its polarity merely by splashing the field connection to the positive terminal of the battery. Wouldn't that achieve the same result as the above mod?

 

Tony

[Gibbo]

I recall back in my early days of tinkering with cars that you could 'flash' a dynamo to change its polarity merely by splashing the field connection to the positive terminal of the battery. Wouldn't that achieve the same result as the above mod?

 

Tony

 

Correct, that was indeed the standard procedure. It also had to be done with a brand new dynamo other wise it could sometimes not bark up at all or perhaps with the wrong polarity. I don't understand how swapping the field brushes round can ever change that. In fact I don't believe it can.

[blodger]

Correct, that was indeed the standard procedure. It also had to be done with a brand new dynamo other wise it could sometimes not bark up at all or perhaps with the wrong polarity. I don't understand how swapping the field brushes round can ever change that. In fact I don't believe it can.

It, the info pamphlet, also has you polarising it for negative earth by connecting battery negative to field and battery positive to D (output).

 

I thought that a bit odd as I just flashed the field with positive for five seconds before connecting and sterting up and that seemed to work OK. I have been looking to find where I discovered that in case I had got it wrong but have not come across it yet.

[jake_crew]

It, the info pamphlet, also has you polarising it for negative earth by connecting battery negative to field and battery positive to D (output).

 

I thought that a bit odd as I just flashed the field with positive for five seconds before connecting and sterting up and that seemed to work OK. I have been looking to find where I discovered that in case I had got it wrong but have not come across it yet.

Only last week I "flashed" a dynamo on the good ship Jake.

 

We've had charging troubles so I took dyno and reg box home to test on one of my old cars. 3A is a typical field current.

 

All worked well at home, so the parts were re-installed on the boat along with some new cabling in a larger size.

 

But as the car is +ve earth and the boat is -ve earth, I had to repolarise.

 

20+ amps now !!!! Yay !!

 

 

BTW ref the ships Vs boats discussion. Submarines are boats - everything else is a target !

[WotEver]

BTW ref the ships Vs boats discussion. Submarines are boats - everything else is a target !

[pistnbroke]

I am amazed at the lack of knowledge the experts have

 

Th field dresistodr is 68 ohms and the ffeld coils 6 ohms unless you have a through bolt short when its 3 .( and that burns out the regulator )

To ploarise link the F terminal to the live on your system so for neg earth thats + to F and Neg to casing.

The cut out is there to disconnect the dynamo from the battery when dynamo output falls below battery volts ...I can tell you how to set it but you need a special ammeter and a voltmeter.

 

 

The two bobin regulators are Compensated regulators ..a turn of fwire carrying current output is wrapped around the voltage regulator so as current rises the output drops...also a turn of wire to drop the output when you put the headlights on ..hence the A and A1.....Dynamos unlike alternators will supply more than the rated current and burn themselves out ...dont exceed 22A

 

The three bobin RB340 has a cutout ,a voltage regulator set at 14.7-15.3 (set at top end) and a current regulator set at 22A ( whilst volt reg is held closed with a crock clip) The three bobin has a resistor across the volt /current reg contacts as well as across the field winding.

 

You can build an electronic regulator quite easily ..there was one in Pratical Electronics in the early 70s .

 

Maax rpm is 9000 rpm

 

You can also make 24v quite easily just drive two dynamos on the same chassis and make one pos earth and one neg earth ...you get your 24v across the two B Terminals on the two regulators..one is + and one -

 

If you need any help just let me know ......hope you like the new avatar ....

Edited May 29, 2010 by pistnbroke