Charging problem

[gbirky]

Soundguy,

I attached another scan.

I'm not sure what you are calling "the positive output from the diode bridge" (I'm no electrical engineer or electonics technician). Is that the wire I've labeled "Y"? The tractor is wired just like I've drawn it. The alternator is actually grounded through the case, so there is no wire there. Of the two wires coming from the alternator bridge circuit, the yellow one "Y", one goes only to the VR. The red wire, "R", goes to the starter solenoid hot side (where the + battery cable is attached - I circled this location on the drawing).

In reference to all of the other posts regarding voltage regulators, this is a permanent magnet type alternator - so there is no field, and therefore field current to vary.

The VR is a small thing, about 2.5 inches long, 1 inch thick, and about 1.25 inches wide. It has an aluminum case and is epoxy filled from the underside. It seems to me that this charging system could work with the VR just being a relay which grounds the "Y" wire that goes directly from the alternator bridge circuit to the VR when it detects a voltage at the battery + "R" wire above some threshold. Does that sound reasonable?

Greg

 

[jimstractors]

My original VR and my used replacement are Yanmar VR's that are sealed with epoxy and fit your description. As I related earlier, mine has 4 wires: 2 to the alternator, 1 to the starter motor + side, and the 4th seems to go to ground. So the regulator must have the diodes inside. The book I have is for a YM169D (very close to the 1401d) and it is set up that way also.
Jim

 

[gbirky]

jwjimbo,
I also have a YM1301D with the setup you are describing. The difference is that the VR for the YM1110D (without the diodes) is about $60, the one for the YM1301D (with diodes) is $100. I can swallow the $60, but $100 is a bit too salty.

By the way, I think the diode pack is normally very robust. Its the rest of the regulator that usually fails. So thats a good way for the parts business to make more money.

It would be very interesting to me to find alternatives since the alternators normally don't fail. What other VR's can we find to replace ours??? Anyone got any ideas?

Greg

 

[Keoke]

The "Y" wire shown is an AC output to the VR. It may be used to tell the VR that the alt is now charging and it is now time to close the alt to bat circuit to permit current flow to bat.
Put a voltmeter on this lead to sure that the latching signal is getting to VR.

It looks like you folks have a 1 phase, constant rate, PM, type of alternator. For a cheap, heavy duty rectifier bridge go to an auto parts house and buy the rectifier bridge from a Delco 10SI alternator (all GM cars 1965/1990). This is a nice all alum heat sink unit that will last forever with your small alt. It is a 3 phase diode bridge unit and you will only use 1 of the three taps. Buy a mini-box and plastic insulator material at Radio and stick diode bridge in box. Box must be grounded well for neg leg of dc circuit.
By the way, the "Y" ac wire is also used to run electric tachometers by converting frequency to RPM on many diesel engines.
Not having to worry about modulating field current puts this project within reach.

cheers,

 

[Soundguy]

If wired as shown, and oem, it still, looks like there are a few things missing in the schematic. Anyway, let us know what you decide.

Soundguy

 

[Soundguy]

That is the trend for most consumer grade electronics... replace, instead or repair. I can remember how easy it used to be to repair a tv... now, you pop open a 36' tv, there is the back of the huge crt, and then a circuit board about 6" x 6".
If any problem develops you trade out the main board for about 2/3's the price of the unit.... makes you wonder..

Soundguy

P.s. .. he should save the diodes.. may prove usefull later.
"By the way, I think the diode pack is normally very robust. Its the rest of the regulator that usually fails. So thats a good way for the parts business to make more money."

 

[gbirky]

Keoke,
In my case, the diode bridge is not in the VR, and the alternator and diode bridge are working. The VR is not. What I need to know is what exactly that VR does, and can it be replaced for less than the $60 I'll have to shell out for the replacement part.

Greg

 

[Soundguy]

Assuming that, there needs to be a relay or other switch in the circuit.

But I agree... if the ac voltage is there.. he has the basic makings of the charging system.. just needs to rectify it, and regulate it.. the easy parts.. as generation was the 'hard' part.

soundguy

"the "Y" wire shown is an AC output to the VR. It may be used to tell the VR that the alt is now charging and it is now time to close the alt to bat circuit to permit current flow to bat.
Put a voltmeter on this lead to sure that the latching signal is getting to VR."

 

[gbirky]

Soundguy,

As you say, it is an "interesting" and "wasteful" solution. These tractors burn so little fuel as it is, that a little extra wasted probably isn't noticed. My question still remains. Is the VR in this setup just a solid state relay that grounds the "AC output" of the alternator?

Its not that I'm not going to pay the $60 to replace the VR with the correct part, I just want to know what the darn thing does! And if there is an inexpensive equivalent solution - I'd be interested.

Greg

 

[gbirky]

Sorry there Soundguy,

I posted my question just after you posted the answer.

So the system would function properly if the VR in the diagram is just a relay to ground the AC from the alternator when the battery voltage goes above say 13.5 Volts?

Greg

 

[bruce1966us]

I know I am shooting myself in the foot from the Yanmar parts outlook but the Kohler regulator is $36 retail. I forgot to get the part # from the shop but will get it ASAP.

Thanks,
Bruce
parts@yanmartractors.com

 

[Keoke]

Voltage regulators sense system voltage at battery and then tell the alternator what the charge rate ought to be. Voltage at battery is proportional to electrical load and battery state of charge. When load is high (voltage low) alt is told by VR to charge high and when load is low and battery is up (voltage high) alt is told to charge low. Keep in mind we are talking about battery voltage here and not alt voltage. Every voltage regulator has a SENSOR tap or wire that is tied to the bat B+, the closer to the bat post itself the better. This input is how the VR knows what the bat voltage is.
Once the VR gets this info it then modulates the alt output by varying the field current in the alt. Hi fld current gives a high alt charge rate. Mechanical (adjustable) VR's will use a vibrating relay coil to vary field strength and solid state units use Zenner diodes to cycle a switching transistor that turns the field current on and off at a rapid rate. The rate of ON time compared to off time is proportional to system voltage.
Low voltage gives more ON time and high voltage more OFF time.
The above is the same for all voltage regulators, so getting something other then the OEM unit to work on your tractor is not hard to do.
They are two types of field circuits, the "A" type and the "B" type. In the "A" type the field coil is fed B+ from the bat and the VR modulates the gnd side to vary the field strength. Most, but not all, solid state units are A's.
In the "B" type the coil is grounded at one end and the VR modulates the B+ into the input end.
You need to know which type you have (A or B) before you can shop for an other then OEM replacement.
The cheapest and most simple (two wires) "B" type VR would be from a Chy corp vehicle about 1965 to 1980 this is a mechanical unit. The later Chy corp vehicles used a "A" type solid state unit, also two wire.
Hopes this helps.
If you can send a wiring print of your system it would help.

cheers,

 

[gbirky]

Keoke,

I appreciate all the information, but I still don't think you are getting the picture. This is a PERMANENT MAGNET alternator. There is no field, or field current to vary. I have already attached a scan of the diagram for this charging system. I'll attach it again here.

My question is a simple one. Will the system charge properly if the VR is just a relay which closes to ground the AC from the alternator when the battery voltage goes above say 14 Volts. If so, where can I obtain such a regulator/relay.

Greg

Greg

 

[Keoke]

Your post of 4/25/02 said that both your alternator and DIODE BRIDGE are working fine. I assumed that the diode bridge that you are talking about is in the alt. If this is the case then you have DC not AC coming out of the alt.
You cannot do anything with the AC coming out of the alt until you change it to DC. Look at my post on using the diode bridge from a Delco 10si alternator to do this job.
You cannot run the AC to ground since 1/2 of the sine wave would be a dead short (pos to neg).
All you need to do on your unit is convert the AC output to DC with the diode bridge. No cut out or relay is required since the diode bridge between alt and bat would be in reverse bias and no current can flow from bat to alt with engine off.

cheers,

 

[gbirky]

Keoke,

Did you take a look at the diagram I attached to the last post? (I attached it here again). The diode bridge is on the back of the alternator and is working, but the regulator is not. There are two wires from the alternator - one goes to the VR and this is AC, unrectified. The other wire from the alternator goes to +B, and this is rectified. The VR has 3 wires. One goes to the alternator AC as I said above. The other two wires from the VR go to +B and ground.

If the VR senses +B voltage, and closes a relay to ground the alternator AC, I think this would cause the system to stop charging. The rectified output of alternator no longer produces voltage. All I'm trying to do is figure out what exactly the VR does in this setup. It doesn't rectify, because the diode bridge on the alternator does that. It cannot regulate charging by varying field current because the alternator field is from the permanent magnets in the alternator. How does this setup vary charging. Does it just turn charging off by grounding the alternator AC when +B voltage is high enough? That is all I want to know.

Greg

 

[bruce1966us]

Here is the Kohler part# 41-403-05 This is a B+ type regulator rated for 15 amps.

Bruce

 

[Keoke]

Greg, I know you got 30 AC at point Y at alternator. You should also get 14/15 volts DC at alt point R which is the DC output of unit. If you don't get 14/15 volts here and have 30 volts at point Y then you have a problem with your alt diodes coverting AC to DC. Most likely open diodes.
Since your alt has a PM field, taking wires Y and R off at VR should let your alt run wild (charge max) if it is a full working unit.
Don't really understand your VR role in circuit as shown.
A maybe theory here would have the Y wire sending a signal into VR that turns on a bleeder circuit only with engine running (AC signal). Bleeder circuit would go off with engine thus taking care of a battery back feed problem when engine is off.
A voltage regulator acting as bleeder unit and dumping off excessive charging voltage to gnd at VR is not comon but has been done with low amp units. Since this is a low charge alt we are not talking of a lot or wattage (heat) here. Soundguy mentioned this type of VR in his post earlier.
Also, if you show 15V at alt R point but not at bat then with engine running try hooking a heavy jumper wire from terminal R at alt to bat B+ and then measure bat voltage again to check this out. If you have 14/15 DC at alt term R and just 12.6V at battery then my guess is an open between these two points.

cheers,

 

[Soundguy]

Not exactly. ( yes and no )

A charging system with a shunt ( like a zenir diode setup ) could be used.. but there are much better ways to do it.

I would personally rectify it through a bridge rectifier, then find a solid state regulator, ( may be hard to locate for that amperage load, but could be made with either a bank of lower power devices, or could be made with a 2n3055 transistor, in a series pass regulator circuit. )
Then filter for emi/rfi, and on to the battery. But that is just me....

Soundguy

 

[Soundguy]

This is good infor for the alternator people.. laid out nice and easilly understandable.... unfortunately this guy has a dc generator.. fixed perm./ magnets for field.

Regulating charging current is either going to be solid state and elegant.. or a variable shunt, down , dirty, and wastefull.

Soundguy

"Voltage regulators sense system voltage at battery and then tell the alternator what the charge rate ought to be. Voltage at battery is proportional to electrical load and battery state of charge. When load is high (voltage low) alt is told by VR to charge high and when load is low and battery is up (voltage high) alt is told to charge low. Keep in mind we are talking about battery voltage here and not alt voltage. Every voltage regulator has a SENSOR tap or wire that is tied to the bat B+, the closer to the bat post itself the better. This input is how the VR knows what the bat voltage is."

 

[Soundguy]

I agree.

The schematic as posted .. is missing a bit of needed circuitry. Could this have been some 'non-working wizadry from a previous owner trying to sell the tractor?
I soppose that the vr could have a large variable resistor setup dumping some of that ac to ground before conversion, and that wouls be protected by the diode bridge when the unit was off ( no reverse flow to discharge the battery )
Again.. terrible design... I would change it to solid state... but then... not my tractor... Would probably be alot easier to just buy the oem part.
I know the guy is just trying to understand the circuit as wired.. but it has defficiencies ( #1.. it doesn't charge, #2 there is some question as to wether certain parts are working, and #3, wether it is plumbed correctly. )
Anyone have a shop manual for this tractor that shows a charging schematic?

Soundguy

""Greg, I know you got 30 AC at point Y at alternator. You should also get 14/15 volts DC at alt point R which is the DC output of unit. If you don't get 14/15 volts here and have 30 volts at point Y then you have a problem with your alt diodes coverting AC to DC. Most likely open diodes.
Since your alt has a PM field, taking wires Y and R off at VR should let your alt run wild (charge max) if it is a full working unit.
Don't really understand your VR role in circuit as shown.
A maybe theory here would have the Y wire sending a signal into VR that turns on a bleeder circuit only with engine running (AC signal). Bleeder circuit would go off with engine thus taking care of a battery back feed problem when engine is off.
A voltage regulator acting as bleeder unit and dumping off excessive charging voltage to gnd at VR is not comon but has been done with low amp units. Since this is a low charge alt we are not talking of a lot or wattage (heat) here. Soundguy mentioned this type of VR in his post earlier.
Also, if you show 15V at alt R point but not at bat then with engine running try hooking a heavy jumper wire from terminal R at alt to bat B+ and then measure bat voltage again to check this out. If you have 14/15 DC at alt term R and just 12.6V at battery then my guess is an open between these two points.

e.""