Alternator wiring

[(unknown)]

I recently purchased a surplus alternator for an off grid application in upstate NY. The house will be powered by wind and a biodiesel. The engine is a Volvo MD2B 2 cyl marine diesel and will charge a 1000A battery bank. The Alternator is rated at 28V and 240A and is water cooled. I'm new to alternators and would like some input on this thing. I believe it's a permanent magnet design.

Anyway the deal is this- I need to connect this alternator to a Xantrex 24V regulator for battery charging.

I removed the internal regulator from the alternator and am now faced with trying to hook up the Xanterx regulator without blowing anything up. I'm confused as to the field and stator wires, not sure which is which without completely disassembling the whole alternator.

Here's some pictures, maybe some clues for you all:

There's 2 wires towards the bottom- one was connected to the old regulator marked F. I'm assuming field.

The other was unmarked, so assuming stator???

Sorry for the huge picture..


huge pic

ok what is up with everyone posting oversize pics today?? the rules here are that images have to be less than 150KB and less than 640 x 480 pixels to be posted here or they are subject to removal. i made your photo a link this time next time i will just remove the picture or your entire post at my discretion.
Kurt  

[electronbaby]

i dont even know where to begin. If you are so sure its a PMG, then why would it have field windings? It looks like the original regulator was far more substantial than anything Xantrex would make. Why did you remove it? could you have gotten it to do what you wanted by simple modifications?

[(unknown)]

The literature describes it as brushless- Is there a brushless alternator that isn't PM? dumb question? but then again I know next to nothing about alternators.

The regulator on this alternator controls it to a setting of 28V. I figured not ideal for charging a battery bank.

The xantrex regulator is a multistage regulator.

Matteas

[electronbaby]

spin it. if you get voltage out, then its a PM.

Short out the output wires. If it is hard to turn, then it is a PM.

Im not sure what speed you will be spinning it, BUT, now that you have removed the internal regulator, you have to be careful not to spin it too fast, because you need to be careful not to over voltage the Xantrex controller (unless you are using an MPPT). If you would have kept the internal regulator intact, you would not have to worry about this, and you could have fed the output from the internal regulator, right into the xantrex controller and it would have made your life easy. It wouldnt have been super efficient, but it would have worked.

[(unknown)]

RoyR KB2UHF- I can reinstall the regulator and spin it- no problems there. However My thoughts were that a xantrex regulator piggybacked on top of the existing regulator would do little for voltage control. ie higher than 28V for bulk charging.

Matteas

[electronbaby]

There was no way of adjusting the internal regulator for 30v? I dont see why you are not just connecting it to the batteries directly through a rectifier. The batteries will hold the voltage down until they start to become charged. At that point use a diversion load controller to take care of any over-charge possibility. You still have to be careful not to let the charging current exceed the capacity of the dump load at full charge.

How do you expect to control engine throttle vs. output voltage /RPM?

If you want more efficiency, let the alternator voltage rise and use an MPPT controller to charge your batts.

http://www.fieldlines.com/story/2008/4/15/19555/1553

[Flux]

What a muddle!

What is this Xantrex controller? I am not aware that they make alternator controllers so if they do I can't help. If it is a normal Xantrex controller I can't think of one that handles 240A.

If you have wind as well then I would let the alternator do the bulk charging and let wind top it off. I see little point in running an engine to do the final stage charging if you have other means.

If it is a PM alternator you can use engine speed to control the output but I seriously doubt that it is a PM if it has an internal regulator. It could be brushless, they exist in various forms and you would then have to supply it with suitable field.

Without more knowledge of what you are doing and the units you intend to use I will not comment further as I see so many pitfalls that I don't want to advise you to to do something that may need a fair bit of specialist knowledge.

Flux

[Flux]

After seeing your new comments to Roy you seem to have some form of vehicle alternator designed to charge a battery for normal applications. At 28v it will not completely charge and equalise a battery that has been well discharged but it will get it up to about 80% charge quickly.

If you keep it there during low wind and let your wind do the final charging via a Xantrex controller using diversion mode then you would probably get by but you mustn't set the Xantrex below the alternator volts or it will divert from the alternator.

If you feel you must use the alternator to do the final stage charging then you will have to defeat its internal regulator ( your problem) and if you rely on the Xantrex for the charge control you will need to keep the peak alternator current below the diversion limit for the Xantrex.

Without knowledge you will have to fool the alternator best you can. It is perfectly possible to provide field externally even if it is brushless. I also think with a bit of ingenuity you could raise the internal regulator voltage with a series diode in the sensing circuit but no hope if you don't understand these things.

Now I have some idea what you are doing, Don't try to tie the Xantrex regulator into the field of the alternator it wasn't intended to do it. Similarly only try the xantrex in diversion mode, it won't handle an unregulated alternator in solar charge mode.

Just treat your big alternator ( whatever it came off) as a car alternator and there is lots of information on using them without the regulator. Watch you don't over cook the batteries. The Xantrex needs a dump load chosen to keep it within its limits, if your alternator exceeds this current limit you will lose control of the charging and gas the batteries,

[(unknown)]

Flux- The problem I have right now is I'm unsure of the type of alternator it is. If it's PM I realize the xantrex won't do a thing.

Like Roy mentioned I gotta spin test this thing first.

I do have a 1000w wind turbine and it may be the best option to equalize with.

Here are some spec's if you're interested, maybe some clues.

http://www.lechmotorenus.com/downloads/sf252_241_e_15042005.pdf

This is an excerpt from the product description:

An integrated voltage controller governs the

generator and monitors its functioning. This

includes all the necessary governing,

monitoring and control functions.

A control amplifier with power transistor

matches the excitation current to the given

load situation to provide a stabilized 28V DC

output voltage to MIL STD 1275.

The generator can also be operated without

a battery as there is an integrated load

dump.

An integrated monitoring circuit ensures that

high and low voltages are detected and

limited.

Temperature monitoring of the connected

battery bank affords a further useful

function. This sensor is used to avoid

overheating by changing the output voltage.

Matteas

[Flux]

From that it is obvious that it is not PM. It is some form of brushless construction but has a normal field for excitation.

"A control amplifier with power transistor

matches the excitation current to the given

load situation to provide a stabilized 28V DC

output voltage "

This is normal voltage regulator operation and it works whether it has slip rings or is brushless.

You would probably be well advised not to mess with it unless you are familiar with such things. The field excitation may be tiny if it is a conventional brushless machine ( which I suspect it isn't) it may be comparable with a normal brushed alternator if it is an inductor type construction. The description doesn't give much away ( probably for obvious reasons).

Try to use it as it is for charging and stop when the charge drops to say 20A ( it gets uneconomic to run an engine for the lower currents). Let the wind do the final stage using the Xantrex, preferably switch the diversion controller out when using the engine.

Don't even attempt to feed the Xantrex to the alternator field and if you fool the alternator regulator to use the engine for final charging make sure you limit its output to a value the Xantrex can cope with as I said before.

That is a nice alternator and should do well. With a modified regulator it would be perfect but without experience I wouldn't advise you to mess with it unless forced to.

Final stage charging and equalising with engine power is wasteful, try to use it for the bulk charge where you can get most of the energy into the battery.

Flux

[(unknown)]

Flux-

"Pin A: Kl. 15, drive switch

This pin is to be connected with the positive pole of the on-board supply via a switch contact. When the

contact is made, an excitation current flows in the generator (max. 2 A) and the generator starts up at the

appropriate speed to charge the battery."

So it takes a 2A supply to get it going.

Thank you for making clear the difference between PM and other types of alternator!

Getting back to the xantrex multistage controller. I understood that this is similar to a balmar max charge design used in the boating world. Those folks hook the regulators up to very powerful alternators for charging their battery banks.

Are you saying that this alternator would overpower this type of regulator?

Matteas

[Flux]

As you give no details of your proposed Xantrex regulator I can only assume that it is something like a C60 used for solar and wind control I am not aware of xantrex making a dedicated alternator controller, I  may be wrong but I don't associate them with that field and you would need to link to what you have in mind.

There are special alternator controllers used in the boating world that do actually replace the existing alternator regulator and these would be perfectly suitable if you can adapt them.

There in absolutely no reason why your alternator ( seemed aimed at the military market) would have identical regulator connections and it would be up to you to make sure it was compatible.

Many are happy to work on the try it and see basis, but unless I know what is in the alternator and what is in the regulator I won't do such things unless I have specific instructions what to do and an assurance that it will work if I did it.

Your alternator is not intended for modification with the use of some other regulator and I suspect it's own regulator is potted so as not to be easily modifiable. There is no reason why another regulator can't be used as long as you know what you are doing.

If you have enough knowledge to do this you would probably have enough to build your own regulator it's not rocket science but not for someone with no experience.

You have confirmed that the excitation takes less than 2A so the requirements are well within any alternator controller used in the marine world.

"and the generator starts up at the

appropriate speed to charge the battery."

I really don't know what that means, this thing may be intended for a charging scheme where the engine speed is related to the load. Normally the engine speed is not related to state of battery charge. As long as you have a minimum speed that is all that is required but they may be intending to drop engine speed as the battery charges to save fuel.

If you can clear up the bit about your proposed Xantrex beast it would help but I really don't want to get too involved with connecting one commercial device to another. I don't mind basic help to point you in the right direction.

Flux

[(unknown)]

Flux thanks for your paitence!

The xantrex alternator controller is similar to the balmar unit however the balmar web site has more detailed specs:

xantrex: www.xantrex.com/web/id/594/docserve.aspx

balmar: www.balmar.net/PDF/MC-624%20Manual.pdf

Matteas

[Flux]

Ok that's fine it will do what you want as long as you can sort out the connections. I wasn't aware that Xantrex were in that market.

You will somehow have to get the details for your alternator to find out how to connect.Most vehicle alternators are very similar I wouldn't assume that yours is the same but it could be.

Flux

[(unknown)]

Flux-

This is a very basic wiring diagram.

Here's my take with limited wiring schematic knowledge:

The 3 phase is clear to me (3 wires going to regulator)

I interpret the 2 wires at the bottom as grounds. There were 2 grounds on the regulator.

The two wires connected to the one phase (with circle) seems like the 2 loose wires in my huge picture (possible field?)

The two wires at the top of the diagram going into regulator are +,- I assume. one says 28V the other is harder to see but maybe 6ND.

Anyhow this is sketchy so I'm open to educated guessing.

Matteas

[Flux]

Some of this is guesswork but here goes.

The main 3 phase is internally connected to the rectifier and the dc comes out the + & - terminals.

Field is that pair of leads at the bottom connected to the thick horizontal bar ( bar is field winding, vertical bars are main windings).

The pair of leads above that with the circle over one phase wire is a current transformer for current feedback (which car alternators don't have, they are reactance limited)

I have no real idea why 3 phase goes to the regulator unless it is for a phase reference if phased controlled or just the same as the auxiliary diodes on a car alternator to prevent field current when stationary ( seems most likely).

I can't be sure where the voltage sensing is taken from, it could be rectified in the regulator from the 3 phase, it could be taken from the top 2 supply leads.

My instinctive guess is that connection C is the sensing volts and it is referenced to D battery ground. If I am right then you can use the existing regulator, you fool it by feeding C at a potential that is a fraction below battery volts via a potentiometer. One end at ground one end at battery volts and the slider to C.

This sensing could easily be taken from point A so that it doesn't drain battery when alternator is switched off.

You will need to prove that C is the external battery sense and if so it is easy.

Failing this you could use the xantrex regulator as the field is not committed once you remove the internal regulator so you can connect it to suit the xantrex.

You have a problem in that you can't use current sensing and you may have to restrict engine speed or power to keep current within limits unless the xantrex has volt drop current sensing ( I don't want to get that involved).

Assuming that connection C is what I think it is then you have an easy solution.

Flux

[(unknown)]

Flux- cracking the riddle- nice!

I just dug this up

Integration instructions for electrical connection

Connecting the signal plug into the on-board supply:

Pin A: Kl. 15, drive switch

This pin is to be connected with the positive pole of the on-board supply via a switch contact. When the

contact is made, an excitation current flows in the generator (max. 2 A) and the generator starts up at the

appropriate speed to charge the battery.

Pin B: Charging check

In the controller, this pin is connected to ground if the generator is not charging. An indicator can also be

connected directly. The contact can take a maximum of 0.5 A. The indicator can be placed on the positive

pole of the on-board supply.

Pin C: Battery sensing

This pin is to be connected with the positive pole of the battery. The generator governs the on-board

supply voltage such that the set voltage is maintained at this point.

Pin D: Battery ground

This pin is to be connected with the negative pole of the battery.

Pins E and F: Battery temperature sensor connection

The battery temperature sensor is to be connected to these pins using two leads. Neither pin is to be

connected with the negative or positive poles of the on-board supply.

Matteas

[Flux]

Ok you are home and dry.

If you link the sense directly to the battery it will regulate at the makers intended voltage, you can't go lower but you can increase it by potting down the voltage to the sense terminal.  It will then regulate with the sense pin at the same voltage but the battery voltage will be set by the ratio of the divider.

As we have no idea of the impedance of the set point then it will be wise to keep the external potentiometer fairly low. You will only need a small variation so I suggest using a 500 ohm pot with a 5k fixed resistor between the low terminal and battery ground, If you can't follow I will do a drawing.  This will let you work from makers set voltage to about 10% higher and you can keep the temperature compensation if you need to.

Flux

[(unknown)]

Flux- you lost me-

I have a sense of what you're getting at but this is over my head.

I understand mechanics well- I can rebuild an engine, but this I gotta work on.

I was hoping the external regulator route would make this more plug and play. But I'm game to learn if you have the patience. A drawing would be great.

As far as current sensing on the xantrex I don't know, they use an alternator temperature sensor, to cut current if things get too hot.

The thing is, I already have the xantrex controller and would like to put it to use.

Matteas

[Flux]

I will deal with it tomorrow I have a few things to do before bedtime.

I will give you a drawing to use the existing regulator which I think is the simpler option. If I can find enough data on the Xantrex and the associated alternator I will try to give you details for using that.

Flux

[(unknown)]

Flux- very much appreciated!

[Flux]

This should let you raise the volts on the original regulator. I don't know what you do with connection B you may have given details I can't remember.

If you remove the internal regulator and connect one side of the field to batt neg and treat the other field lead as terminal F on the Xantrex connection diagram you should be able to use it but you have no current limit.

Just treat it when connected as shown as the alternator in the Xantrex data, you don't need the change over switch and dual batteries. The terminals marked Pos and Neg are the main alternator terminals from the internal rectifier.

Check this it is from memory.

Red goes to batt pos. black to batt neg ( ground) Brown you make live via switch to generate. Blue goes to terminal F

Hope this hepls. You are in a bit of an unknown region and although I believe this is correct I can't be responsible for any failure.

Flux

[(unknown)]

Flux- I now understand!

In essence this brings the voltage up to near 30.5V give or take.

This is great for bulk and absorption charging.

Here are the connection instructions from xantrex:

The RED wire (in the harness) powers the regulator. Attach

at the positive output terminal at the alternator.

The BROWN (ignition) wire activates the regulator when

+24VDC is applied to the system.

The BLACK (ground)

Plug BLUE (field) and

ORANGE (stator) wires into rear of alternator

I understand you're drawing concerning the field line but where would you connect the stator line? I assume somewhere on the three phase. Does this take care of voltage control?

Your effort is monumental!

Matteas

[Flux]

This is all new to me, I haven't had any experience of marine alternators. With tractors the stator connection usually keeps the black box controller live and if the alternator belt breaks you loose all control of the hydraulics.

In this case the stator connection seems to be used for a tacho if fitted. The Xantrex literature seems to suggest that it is optional and you can ignore it if you don't have a tacho. I really don't know if the thing has any function for the regulator.

The data for the other regulator didn't cover this so I was glad to find that Xantrex seem to think you can run without it.

I am out of touch with vehicle alternators but from what I can remember the stator connection is one stator line before the internal rectifier so it would be one of those ac wires going to the original regulator. Any would do but the frequency of your alternator could be widely different , I have no idea how many poles it has.

Flux

[(unknown)]

Flux- You're help has been well received. I feel like I have swallowed a huge amount of new info.

Thank You,

Matteas

[(unknown)]

I did more research- called balmar- they said the stator connection is only for rpm monitoring.

Flux you were right on about that.

You mentioned there would be no current limit with the xantrex regulator. Isn't that the whole idea behind a voltage regulator?

Just curious on your thoughts.

I'm pondering which way to go- original regulator or marine type regulator.

Matteas