Trolling Altenator

[aldeburgh]

I am in the process of making a trolling altenator ,i have a Ametek 40 VDC Nominal 280892F7 Permanent Magnet Generator with works well but when i attempt to rig it up to a 12 battery via an amp meter to test the amps produced the altenator runs.
I need something that only allows current to pass in one direction.
Thanks

 

[VicS]

A diode ???

EDIT
I guess the trouble is that it is not in fact an alternator .... that would have diodes of its own ... It is a DC generator or dynamo


2nd EDIT

it is actually a motor that can be used to make a generator such a a wind turbine

3rd Edit

See http://www.tlgwindpower.com/blockingdiode.htm

 

[mjcoon]

A diode ???

Yes. Anyone who did not know that must already be outside their comfort zone...

Mike.

 

[MASH]

Heavens above! Even by the "standards" of this forum this post is beyond belief.

Stick to meccano buddy. leave electrickery to the complete idiots!

 

[OldBawley]

The Ametek 40 V motor is no good for a trolling generator. It needs to many revolutions to charge.

I use an Ametek 40 V short version to generate from wind.

I winter in a low wind area and needed a windgen that charged at low wind speeds. ( Full time liveaboard. ) Solar is fine, but winter is long and dark even in the Med. Sometimes two or three days without sun, and days are to short to fill the battery’s 100%.
Build starting with the Ametek and had to go for a big two bladed propeller. Big means power, then I needed just a few more revolutions to charge at more than 14, 3 volts so geared the generator.
The Ametek now loads real good thanks to the big diameter ( 1,7 meter ) and the gearing.
Even geared ( prop 30 teeth, Ametek 17 teeth ) the charge is mostly 3 to 5 Amps, but commercial windgens charge nothing at that wind speed.

In winter and anchored I build the generator up, takes 5 minutes, going for a sail or in summer, the machine is stored.

 

[KellysEye]

I don't know where you will be sailing but towed turbines have been known to be bitten off by sharks in the Atlantic, they think it's a fish. There are some sharks in the UK.

 

[rotrax]

Passing a current via an ampmeter through the coil with the unit static will tell you little AFAIK.

I am surprised the unit " Motors " though.

I would expect the magnetism caused in the pole pieces to cancel the poles of the permanent magnet rotor, causing stalling.

This is, in fact, how many motorcycle permanent magnet alternators are regulated.

The Zenor diodes " clip " the output waves, sending voltage below about 14.5 to the battery, and voltage above that into the winding where the increased magnetism in the coils interferes with the rotor's magnetism, causing charging to stop-or at least reduce significantly.

This is perhaps an oversimplification, but its pretty much what happens.

 

[mjcoon]

Passing a current via an ammeter through the coil with the unit static will tell you little AFAIK.

I am surprised the unit " Motors " though.

I would expect the magnetism caused in the pole pieces to cancel the poles of the permanent magnet rotor, causing stalling.

This is, in fact, how many motorcycle permanent magnet alternators are regulated.

The Zenor diodes " clip " the output waves, sending voltage below about 14.5 to the battery, and voltage above that into the winding where the increased magnetism in the coils interferes with the rotor's magnetism, causing charging to stop-or at least reduce significantly.

This is perhaps an oversimplification, but its pretty much what happens.

Little or none of that makes sense to this one-time "applied physicist". Nor chimes with references already given for usage of the cited device. Have you a reference to a write-up, preferably one that spells "zener" correctly?

Mike.

 

[rotrax]

Little or none of that makes sense to this one-time "applied physicist". Nor chimes with references already given for usage of the cited device. Have you a reference to a write-up, preferably one that spells "zener" correctly?

Mike.

I was I/C training for a major Japanese Motorcycle manufacturer.

The product line used permanent magnet alternators that look little different to wind generator alternators, and the regulator regulators appear to be very similar-the single phase and three phase windings just have extra ZENER diodes. Sorry for the spelling-just been planning our summer cruise and had been looking at Zenor Point near Lands End!

What exactly dont you get?

A modern reg/rect unit rectifies and regulates every output sine wave from the generator, in the manner I explained. At least that is what the nice man from Kogusan-the company who made our equipment-told me when he came all the way from Japan to fill me in.

Some, like the ones designed by my old mate Ernie Brandsden incorporate a large capacitor which charges up from the generator and then lets go through the ignition allowing the battery to be discarded for competition use, or allow starting with a flat battery on a streetbike.

The appalling old Lucas Zener diode system dumped excess voltage through a large heat sink to earth when the diode's trip voltage was reached.

I would get about 1.75 BHP extra from one of our bikes on a chassis dynomometer by disconnecting the alternator wires.

This BHP loss was directly atributed to the magnetism in the alternator when working normally.

I hope this helps.

 

[mjcoon]

What exactly dont you get?

Let's start with a simple question. An alternator is so called because it generates AC. Hence the need for some sort of diode(s) to get DC. A DC device usually has a commutator which avoids AC by switching the armature coils to reverse the polarity in synchronism. (All this is from memory! I may look up Wikipedia if necessary...)

So do the devices from your bikes have commutators (I presume not) and were the permanent magnets stator or amature?

And do the devices in the OP enquiry have commutators as befit DC devices with no electronics?

Mike.

 

[rotrax]

Let's start with a simple question. An alternator is so called because it generates AC. Hence the need for some sort of diode(s) to get DC. A DC device usually has a commutator which avoids AC by switching the armature coils to reverse the polarity in synchronism. (All this is from memory! I may look up Wikipedia if necessary...)

So do the devices from your bikes have commutators (I presume not) and were the permanent magnets stator or amature?

And do the devices in the OP enquiry have commutators as befit DC devices with no electronics?

Mike.

I see-your information on alternators is quite old.

AFAIK two types of alternator are in common use, permanent magnet and field coil rotor ones.

Field coil alternators are controlled by increasing or decreasing the amount of current flowing in the rotor coil, the current reaching the fast spinning rotor through slip rings and brushes.

More current= more magnetism=more voltage/output.

Permanent magnet alternators have fixed magnetism,either by an internaly rotating rotor-Lucas, or external "Saucpan lid " types as used on up to date motorcycles and some cars.

The type the OP is using is a permanent magnet type. This, as another poster said, will require spinning at high speed to give useful output. If it is spun, the two or three output wires will give AC current-up to 70 volts, depending on speed.Two wires=single phase, three wires= three phase.

The AC voltage on both types is nowadays rectified into DC at around 12.7 to 14.7 volts by Zener diode regulator/rectifiers which work in the way I said earlier-every output sine wave is " chopped "-the excess current going back to the winding where it causes the winding to become more magnetic, thus the + and - poles oppose each other so cutting output to the right level.

I am currently living in Southern Spain and have no access to my archive of training stuff which is still at home.

You may try googleing Boyer Bransden. They used to have a website explaining how their kit worked.

Please accept my apology if you think I am being patronising-that was never my intention.

I hope the above helps.

 

[mjcoon]

I see-your information on alternators is quite old.

AFAIK two types of alternator are in common use, permanent magnet and field coil rotor ones.

Field coil alternators are controlled by increasing or decreasing the amount of current flowing in the rotor coil, the current reaching the fast spinning rotor through slip rings and brushes.

More current= more magnetism=more voltage/output.

Permanent magnet alternators have fixed magnetism,either by an internaly rotating rotor-Lucas, or external "Saucpan lid " types as used on up to date motorcycles and some cars.

The type the OP is using is a permanent magnet type. This, as another poster said, will require spinning at high speed to give useful output. If it is spun, the two or three output wires will give AC current-up to 70 volts, depending on speed.Two wires=single phase, three wires= three phase.

The AC voltage on both types is nowadays rectified into DC at around 12.7 to 14.7 volts by Zener diode regulator/rectifiers which work in the way I said earlier-every output sine wave is " chopped "-the excess current going back to the winding where it causes the winding to become more magnetic, thus the + and - poles oppose each other so cutting output to the right level.

You may try googleing Boyer Bransden. They used to have a website explaining how their kit worked.

Please accept my apology if you think I am being patronising-that was never my intention.

No, I didn't think you were patronising; I was also trying to avoid that...

All except the bit about zener diodes is familiar. I recall stuff about using field coils in series or parallel with armature coils, giving different current/torque/speed characteristics. And I would like to know about what seems to be a dual-purpose power use of zeners. I am only familiar with their use as voltage reference.

But not sure of the relevance of all this stuff, since despite the OP's use of "altenator" the product websites refer to the devices as "generators" or "motor/generators". But I do realise that commutators (and their brushes) were always a weak point, in motors or generators. (I even tried to replace a burnt-out 14-segment motor commutator with a fabricated one when I was an apprentice; not successful!)

Mike.

 

[rotrax]

No, I didn't think you were patronising; I was also trying to avoid that...

All except the bit about zener diodes is familiar. I recall stuff about using field coils in series or parallel with armature coils, giving different current/torque/speed characteristics. And I would like to know about what seems to be a dual-purpose power use of zeners. I am only familiar with their use as voltage reference.

But not sure of the relevance of all this stuff, since despite the OP's use of "altenator" the product websites refer to the devices as "generators" or "motor/generators". But I do realise that commutators (and their brushes) were always a weak point, in motors or generators. (I even tried to replace a burnt-out 14-segment motor commutator with a fabricated one when I was an apprentice; not successful!)

Mike.

AFAIK modern permanent magnet alternators consist of a multi-pole armature or winding, single or three phase.

This is engineered to fit inside a " Saucepan lid " rotor, the magnetic material, often ferrite or rare earth magnets, is affixed to the right angle bit of the saucepan lid. This keeps centrifugal force holding the bits-which can be hard to mechanicaly join-in the right place. The generator could easily reach 14,000RPM on a modern high performance motorcycle.

The AC output is fed into a Rectifier/Regulator which has one or three internal circuits, depending on single or three phase.

Lets take a single phase and draw a simple graph. Straight horizontal line for the base 0 volts, vertical line for voltage, both above and below the line.

Now draw a typical output sine wave, half above and the other half below the zero base line, up to about 70 volts on the vertical scale.

Now imagine the rectifier has done its job with all its solid state magic and only the current travelling in the direction we need is allowed any further.

If you mark the upper sine wave-we will use that one as pos to neg-at approx. 14.5 volts on its left side, and again at the same point on its right side, the voltage up to and including 14.5 on the way up, and from 14.5 down on the opposite side of the sine wave, will be sent to the battery and systems of the vehicle.

The voltage above this goes back into the generator where the magnetic interference between the permanent and generating poles takes place, so limiting further output.

It must be realised that the Zener is acting as a switch to the other solid state units, and that EACH OUTPUT WAVE is being so controlled-all at 186,000 miles per second!

The Zener's voltage reference is what switches the Thyristors in the circuit to get the required speed of switching.

These units are pretty reliable, diagnosis is easy-they work or they dont-and are not too expensive.

I modified many, many Lucas equipped British motorcycles with Chinese, Japanese, Indian and British rectifier/regulators.

They improved the electrical performance of the old Lucas alternators no end, and, probably purely subjective, seemed to make the engines run sweeter.

I hope you can get the gist of my ramblings. Drawing the graph might help.

You mention the coils in series and parallel-the antique and quite frankly bloody awfull Lucas 6 volt systems would use the lighting switch to bring in extra coils when the lights were needed. It was often neccessary to have the lights on all the time to stop the battery boiling dry!

And the switch would not last long either........................

PS- a conventional segment type commutator would not last long at 14,000 RPM either-nor do slip rings have a long life at those speeds.

Modern generators are much different these days.

Making a commutator-wow-tricky or what. Respect.

 

[OldBawley]

The Ametek the OP is referring to is a DC motor. They ware used in big computer tape drives, are high quality made, use four very big brushes to transmit power to / from the anchor windings.
Big diameter shaft and sturdy high quality ball bearings.
If spun by wind they produce DC, the voltage depending on the revolutions. A diode is needed to prevent the motor from using battery power to spin the propeller. I use a Schottky diode.

The output voltage has to be monitored not to exceed the charging voltage of the battery’s. A charge controller with dump resistor can be used or a more or less intelligent human.
In my case, the propeller is tied down with a piece of string when the battery tension has reached 14,3 V for about one hour. After that, the solar system takes over stage two, three and four of the charging process.
KISS.

 

[VicS]

The Ametek the OP is referring to is a DC motor.

Quite!
A fact which I pointed out in #2

Mention "alternator" and they all go off at full pelt demonstrating their superior knowledge on the subject without checking on the basic facts.

 

[rotrax]

Quite!
A fact which I pointed out in #2

Mention "alternator" and they all go off at full pelt demonstrating their superior knowledge on the subject without checking on the basic facts.

OOPS!

 

[Skipper_Christoph]

Diode ?

 

[rotrax]

Diode ?

No.

Wally.

 

[VicS]

Diode ?

Post #2