Charging problem

[gbirky]

OK Soundguy, so you know more about it than me. No surprise there...

All I was trying to say, is that the alternator is a simple permanent magnet type. There is always a load on the engine to turn it. The point is that the diodes without any load will provide a current which is not what I consider to be DC. That is, it is a series of bumps, so if you do a frequency analysis, there is significant power at frequencies much higher than zero. The average is positive, because the bridge rectifier creates the effect of "reflecting" or "folding" the negative part of the alternating cycle to positive. A true voltage regulator in my mind would provide a constant voltage output with a great majority of the power at a frequency of zero regardless of whether there is a load or not. I don't believe this is what the alternator and voltage regulator on my YM1110D does. One wire from the alternator goes directly to the battery, the other to the VR. The other wires on the VR go to battery and ground. I guess its possible the the VR actually does some feedback based variable regulation, but I rather doubt it.

I'll have to check it out, but I'd bet that without the battery, the voltage will be a wave form, not a constant.

By the way, I think you attached a bitmap file. My browser couldn't read it.

Greg

 

[normde2001]

Sure hate to oversimplify this thing, but if it were mine I would take the alternator and/or regulator apart and see which has the diodes and check them with a meter. (Continuity in one direction, open in the other). Should be either 3 or 6 of them.

 

[Soundguy]

"All I was trying to say, is that the alternator is a simple permanent magnet type. There is always a load on the engine to turn it. The point is that the diodes without any load will provide a current which is not what I consider to be DC. That is, it is a series of bumps,"

Bottom line.. if current flows in only one direction in that circuit.. it is dc...
It is unfiltered dc..

" so if you do a frequency analysis, there is significant power at frequencies much higher than zero. The average is positive, because the bridge rectifier creates the effect of "reflecting" or "folding" the negative part of the alternating cycle to positive. "

Frequency referes to cycles. There is no negative voltage swing in unfiltered , rectified dc. Every second, you will have the native positive wave form, then the redirected wave form.
freq is 0.

"A true voltage regulator in my mind would provide a constant voltage output with a great majority of the power at a frequency of zero regardless of whether there is a load or not. I don't believe this is what the alternator and voltage "

Note that, electrically, a regulator is not a rectifier, and even if packaged together in a block component, it is still two devices. As for a constant voltage with no load, many regulator circuits will accomplish this. In some cases, the regulator itself provides a load. A constant current circuit will do the same, as it has a built predetermined load.

"regulator on my YM1110D does. One wire from the alternator goes directly to the battery, the other to the VR. The other wires on the VR go to battery and ground. I guess its possible the the VR actually does some feedback based variable regulation, but I rather doubt it."

Depends on the age of the unit...The regulator will have a common ground reference, and a reference of the output voltage applied to the battery. Usually this wire is tied right to the charge output of the alternator, rather than run to the battery itself. Electrically, there will be little difference anyway. There will also be a reference for the field coil in an alternator that uses an external regulator. DC generators, and magnetrons will use a slightly different method.

"I'll have to check it out, but I'd bet that without the battery, the voltage will be a wave form, not a constant."

The variation is correct.. that wasn't in dispute...The voltage without a load, or a battery, will look like unfiltered rectified dc... it will have crest to 0 crest to 0
It will not be a true wave form, with no negative voltage swing. A large value capacitor will help cut emi noise on any electrical equipment you are running... an 'L' or 'PI' filter using 2 caps and a choke will kill rfi as well.


Suprising... what browser are you using? bitmaps are a fairly
common pic format. I'll attatch a jpg with this post.

Soundguy

"By the way, I think you attached a bitmap file. My browser couldn't read it."

Greg

 

[normde2001]

Whew!!!....You guys are giving me a headache...I'm outa here.

 

[bruce1966us]

It was a YM1401 to start with right?! That tractor uses a dyno (generator) and puts out AC voltage (25-30 at 1500rpm) which is converted to DC by the regulator. Here's a good one- I have used a Kohler 3 wire regulator with the dyno system on some powerpacks I have built with the 3TR72 engine and it works fine. I will look up the Kohler part number if anyone is interested. These systems are very simple in design which I think is great!

Thanks for all
Bruce

 

[bruce1966us]

A lot of the old Dodges/Chryslers had basically this same system but with higher voltage/amps.

Bruce

 

[bruce1966us]

And just how do you insert an attachment here? Sorry for all the posts!

Bruce

 

[Soundguy]

Assuming the charging system is still stock on his unit.. does it produce the ac, outsource it to a regulator, then bring it back to rectify it? His last post stated that he was told that 'the diode pack' was good.....
On the other hand, if ac voltage is making it to the battery.. that isn't good. ( But it doesn't sound like it is.... it should have been noticible by now ). If that system does have a rectifier built in with the regulator, then there should be no + battery charge output post on that unit.. his message indicated that there was. Unless the + reference was extra excitement for a field coil, in conjunction with a perm. magnet setup. I've seen a a unit set up that way before.

I hope he posts whatever the problem was, as it is getting interesting.

Soundguy

It was a YM1401 to start with right?! That tractor uses a dyno (generator) and puts out AC voltage (25-30 at 1500rpm) which is converted to DC by the regulator. Here's a good one- "I have used a Kohler 3 wire regulator with the dyno system on some powerpacks I have built with the 3TR72 engine and it works fine. I will look up the Kohler part number if anyone is interested. These systems are very simple in design which I think is great!
Thanks for all
Bruce "

 

[normde2001]

Bruce, read the FAQ about attaching photo's. Then make sure the box labeled "Review or attach a file" is checked, click continue, then click on browse to find your file/photo.

 

[gbirky]

Bruce,
I'd like to know the Kohler part number of that regulator. I can get the correct one for $60, but if there is an equivalent for less money - I could go for it.

Greg

 

[jimstractors]

So the bottom line...I probably need a new regulator. The Kohler regulator sounds good if its cheap enough. The Yanmar reg. is about $90.00 new + shipping.
Thanks for all the advice and the science lessons,
Jim

 

[Soundguy]

Anyone have a compiled spec listing for the charging systems on the us and grey yanmars. It is apparent that there is a wide variety of oem parts usage on the charging systems. Ranging from alternators to dc generators / magnetos, etc. Inboard and outboard regulation, and internal as well as external regulators, and rectifier/regulator combos.

Soundguy

 

[Keoke]

Hi folks, in regard to automotive style voltage regulators. These regulators are not desinged to provide a constant flat voltage such as you would find in a high value dc power supply. Instead, they are more of a voltage limiter in that it shuts down or weakens field current whenever the set limit voltage is reached by the alt. This voltage limit number varies, but is somewhere between 13.8 to 14.8 volts for most 12V applications.
It probably would be less confusing if we just called these units "voltage limiters" instead of voltage regulators.
A true permanent magnet alt (no field coils at all) cannot be regulated since there is no way to control the magnetic flux between the field poles. These are usually very low amp units.
On the Yanmar unit, if it is putting out 30volts AC and has no internal diodes then it is charging ok. If the 30 volts AC is going into (combo rectifier/regulator) and no 14/15 dc is coming out of the regulator then it is likely that the rectifier part of this unit is open. If this is a sealed unit (most likely) then unit must be replaced.

cheers,

 

[Soundguy]

A way to think of it would be that the regulator affects the output voltage by modifying the field current.

""Instead, they are more of a voltage limiter in that it shuts down or weakens field current whenever the set limit voltage is reached by the alt. This voltage limit number varies, but is somewhere between 13.8 to 14.8 volts for most 12V applications. ""

"It probably would be less confusing if we just called these units "voltage limiters" instead of voltage regulators."

However it could be argued that a limiter would still be in the 'class' of regulators, due to 'job description'. Even so, Keep in mind that it does not shunt or clip the output or the field, but does modify it.

""A true permanent magnet alt (no field coils at all) cannot be regulated since there is no way to control the magnetic flux between the field poles. These are usually very low amp units. ""

"Cannot" is such a hard word. It would be more correct to say that it would be cost prohibitive, or difficult, etc.
If it has a power output.. it can be regulated. The regulator would be an end stage regulator, ont a middle stage regulator as one that uses variable field coil. Just a matter of how much you want to spend, and how complicated you want to make it.

Anyone remember if this guy had pics of the tractor? If so, he could post pics of the various wiring diagram how it is currently hooked up, and edit the pics showing voltage at check points. Would make it easier to diagnose then.
At any rate, he decided to get a new regulator right?

Soundguy

 

[normde2001]

Therein lies the problem, Keoke, no one seems to know or has said on this forum, where the diodes reside. We know the alternator is not sealed. If the regulator is not sealed, it would sure be a shame to purchase a new one when you have two spares full of parts.

 

[gbirky]

The diodes are mounted on the back side of the alternator on my YM1110D. The alternator is a permanent magnet type. I have attached a drawing of how the alternator, bridge rectifier, regulator, and battery are wired.

I also have an alternator from a YM1100D, and it doesn't have the "diode pack" on the back of the alternator.

Greg

 

[Keoke]

Norm, it seems, but I am not sure, that this unit uses external full wave rectifiers built into the regulator. He has 30 volts AC out of alt but no DC at bat. If AC is making it to regulator but no DC is coming out then it looks like the rectifiers in reg are open circuited. It's time to replace regulator which I think he is going to do.

Soundguy, regulators, as far as I know, modulate field current by turning on and off current flow through the field windings at a rapid frequency (duty cycle). Field on time will be high with heavy electrical loads and low with light loads. Two stage mechanical voltage regulators, a most comon type, also use shunt circuits when in their second stage. Depending whether they are of the "A" or "B" types, these units will shunt either the B+ or the gnd side of the field circuit to shut off field current flow when peak (limit) alt voltage is hit.

On controlling alt output by using an "end stage regulator".

These units work by taking excess current and voltage (watts) and converting the excess to heat. They are not very efficient since there is no point in using fuel to make power and then throw it away.

My apologies to the group for all of this technical garbage.
This charging problem, while interesting, has spun out of control.

cheers,

 

[Soundguy]

Question on the schematic you posted. Does the positive output from the diode bridge connect to the battery, or is it only connected to the vr, and then the vr connected to the battery. ( I see from the schematic that it is drawn that way, just wondering if it was really setup that way... Makes for an interesting regulator circuit if it is. If there are no other hidden parts involved.

Also.. if the units are not sealed.. it could be a replaceable part swapout. I rememner years ago, you used to be able to buy diode packs and buttone style rectifiers off the shelf at some stores.. autozone, etc.
I've rebuilt an alternator to a hard to find peice of equipment one time with an external epoxy rectifier pack, that was 'home cooked', to get a guy out of a bind.... just have to keep in mind component tolerances...


Soundguy

 

[Soundguy]

If he has ac voltage at the regulator, and the diodes are open.. then he could just replace the rectifier (s) just depends on how handy he wants to get.

"Norm, it seems, but I am not sure, that this unit uses external full wave rectifiers built into the regulator. He has 30 volts AC out of alt but no DC at bat. If AC is making it to regulator but no DC is coming out then it looks like the rectifiers in reg are open circuited. It's time to replace regulator which I think he is going to do."

I've seen both the pulse width modulated fields like you mention, and a simple 100% on time variable field density setup as well.

"Soundguy, regulators, as far as I know, modulate field current by turning on and off current flow through the field windings at a rapid frequency (duty cycle). Field on time will be high with heavy electrical loads and low with light loads. "

Two stage mechanical voltage regulators, a most comon type, also use shunt circuits when in their second stage. Depending whether they are of the "A" or "B" types, these units will shunt either the B+ or the gnd side of the field circuit to shut off field current flow when peak (limit) alt voltage is hit.

Shunting the field is a much different case than shunting excess charging current. I've seen many setups that shunt the field to produce a definate 'off state'. In some transistor circuitry negative bias is often used for 'off state' situations ( ( base and/or gate ).

"On controlling alt output by using an "end stage regulator"."

"These units work by taking excess current and voltage (watts) and converting the excess to heat. They are not very efficient since there is no point in using fuel to make power and then throw it away. "

My point. why make it to waste it. But keep in mind that there are also end stage regulators that do not shunt excess supply voltage in order to regulate output voltage. For a simplified idea, pull up the specs on a 7812 from the radio shack web page. Though we are talking about a tip style package with a 500ma to 1amp capacity, the concept is the same.. just a smaller or larger scal application.


"My apologies to the group for all of this technical garbage.
This charging problem, while interesting, has spun out of control."

I wouldn't categorize it as out of controll. And as for techo-info. Seems the more the better. I see no need to appologize either. The topic we are discussing is 'charging systems', and our discussions back and forth, are without a doubt, on topic.
In deference though, I believe that we may be doing a bit more theoreticle work on a tractor charging system than the original engineers who designed it. But heck... it is fun, and that is why we own these tractors anyway... for the hands on experience.

Soundguy

 

[Soundguy]

As an after thought, has anyone considered solar power as a charging alternative.

I had a riding lawnmower which had the magneto go out on it ( no dual purpose starter, etc ).

A bit of polycarbonate a few machine screws and pcb standoffs, and a surplus solar cell , and you have a no-engine-load charging system. Good for the week to week cranks needed for mowing. Not so good for extended headlight or electric attatchment use ( of which I do neither on the lawn mower ).

Soundguy