What am I missing? continued

First, I'd like to say thanks to all wh read and responded to my earlier post. Here's what I've found:

Tractor will charge as it should at all throttles. Start it, charges 10 or so amps, and drops off after a few minutes to 5 amps or so.

My only problem is when I turn the lights on. They seem to pull 15-20 amps for some reason. This will cause a discharge of about 10 amps. I don't have any extra lights on it. There are 3 25 watt bulbs and one watt unknown bulb on the tractor's light circuit.

I'm still puzzled by this. My C never had a problem this way. I'd start it, it would charge at about 10 amps, I'd turn on the lights, and it would bounce the ammeter, ant then continue to charge at about 5 amps. I don't see why this ferguson won't continue to charge with the lights on.

I may have to leave well enough alone at this point. I don't like the situation, but it will run and charge as long as you don't use the lights. I've got to talk to the owner of the tractor and get his opinion. I have not done that yet.

Thanks all. -Andy

I hate shooting from the hip, especially when I have not been in on the conversation from the beginning but you said Ferguson and that made me think of my Ford which has the same reaction to the lights being turned on. With the 2N Ford I have (which is on 6v with a genny) there is a screw adjustment which increases the charge rate of the genny. In winter when I run it at night a lot I have to turn the genny up and keep the lights on to prevent overcharge. In summer I turn it back down and rarely use the lights. I have no clue if this is your situation but I had a few minutes to kill this AM and thought I would mention it.

Are you absolutely SURE those are 25-watt lights? If they were 35 Watts each they'd draw about 15 Amps total on a 6V electrical system.

Are you absolutely SURE about the calibration of the meter? "About 10 Amps" could be anywhere from 7 to 13.

As a general rule, when the system won't pick up the load, ya look at the voltage regulator.

Allan

Volts x amps = watts. So watts divided by volts = amps. On a 6V tractor, you say you have three 25-watt bulbs. Now, 3 x 25 = 75...and 75 divided by 6 = 12.5 amps, which is what your total draw from the lights SHOULD be. Divide that 12.5 amps by 3 lights, and each light SHOULD be drawing just under 4.2 amps. But if you've got a 20-amp draw, that's about a 6.7-amp draw per light, on the average.

What would I do in your position? I'd check the light circuit with a volt-ohm meter. With the light switch on, I'd check output voltage at the switch. If it's at 6V or slightly above, that's where it should be. If it's lower, then I'd check the voltage coming in to the switch. If the input voltage is at 6V or so, but the output voltage is less, then you have resistance in the switch, and you should probably replace the switch.

If the output voltage at the switch is in the correct range, then I'd check the voltage at each of the lights. If there's a voltage drop between the switch and the light(s), then there's unnecessary resistance in the wiring...and I'd replace the light wiring with a new wire, with soldered terminals, and with heat shrink tubing over every connection.

If the voltage goint TO the lights shows no significant voltage drop, then I'd check the bulb sockets to see if there's a voltage drop there. If there's no significant voltage drop anywhere between the switch and the sockets, then the excessive amp draw has to be coming from the bulbs themselves...and I'd replace the bulbs.

What you do is up to you, and I'm sure there are experts out there who would disagree with my methods. But that's just what I'd do.

What is the voltage at the battery with lights off, then on?

Is the ammeter connected correctly with the connection to the battery on one side and the charging system output and ALL electrical loads on the other terminal?

How many amps discharge does it show with the engine off if you just turn the lights on? If it shows your 15-20 amps, maybe your problem is all in an excessive light load. The generator only has so much capacity and the lights may exceed it. Charging system could be OK as is, just expecting too much of it.

Loose fan belt? Dragging bearing on fan or gen? My brother's 9N Ford has a 30 amp gen---don't know about the Ferguson.
I'd look at each light/wire going to it with an ohm meter to see if one of the sockets or wires is shorting to ground---touching ground to create an extra load--but not enough to blow a fuse.

Ok, to answer some questions asked of me...

Ammeter shows discharge of 20 amps with motor not running with lights on. This changes to 10 amps discharge with motor running.

Voltage at battery is 6.3 with nothing on. with motor running, it's 6.7, and with lights on, motor running or not, it's 6.3 volts.

I'm quite sure that the 3 main lights are 25 watt. I opened the casings up while I was re-wiring it to attach new wires and they are marked as 25 watts.

As for the accuracy of my testing equipment? I'm relying on the brand new ammeter on the tractor, and my Digital volt ohm meter. Are either accurate? I can't certify either, but I doubt that my Digital meter is wrong. It is not a cheap one, It's the nicest one from sears and it's not that old.

Allan- I still suspect that the problem is the regulator, but I've tried 3 and they all act the same (or reasonably close). 2 are brand new "made in India", one is about 10 years old "Made in usa" off of my C that worked 3 years ago. I'd like to spend the $75 from NAPA for a new "NAPA Premium" regulator, Hopefully it's made in USA and a good one, But I'm kinda gunshy with 3 other regulators not giving me the response I'm looking for.

Hmmm... Thanks for the responses! Keep the Ideas comming! (hopefully!) -Andy

Not even allowing for what the regulator is or sin't doing, three 25-watt bulbs should only be pulling 12.5 amps total...NOT 20 amps. So apparently there's an extra draw somewhere in the light circuit to begin with. If it was me, I'd be trying to track down what's drawing those extra amps first. WHY? Because once you get the current draw from the lighting circuit corrected, then there's a lot less of a deficit to be concerned with in the charging circuit.

But that's just me, and how I'd approach things. Other folks might go about it differently. But once the current draw from the lighting circuit is corrected, that's one less problem to deal with...because there apparently IS a problem there.

Assuming a properly adjusted belt, I think it needs to be looked at in terms of 2 brush or three brush generator. If the field is grounded direct to frame and it is running at 2/3 throttle, the generator will be putting out all it can. In this condition, if the lights cannot be carried by the generator, and it is a three brush, move the third brush as close to the fixed brush as possible.
If it is a 2 brush, there is no adjustment.
If it will not put out 20 amps full fielded (as above) it needs to be replaced with a gen that can do it, or repaired, it might have a open armature winding or two, Jim