Ammeter question....

[SmallChange]

You have numerous electrical devices in the tractor such as alternator or generator, battery, headlights, starter motor, et cetera. All of them can be connected to an overall positive voltage point and an overall negative (or ground) voltage point. The ammeter is on one of these connections.

If the ammeter is on the connection between the battery and everything else, it will point in one direction when you're charging the battery during typical operation, and the other direction when you use any electricity while the engine's off, such as starting, or using the headlights without the engine. The battery can be a power source or a power consumer, depending whether it's discharging or recharging.

If, however, you put it on the connection between the alternator and everything else, it will only ever point in one direction (or at zero). The alternator is only a power source. If you put it on the connection between the headlights and everything else (admittedly not a very interesting use of an ammeter), it will only ever point in the other direction (or at zero). The headlights are only a power sink.

So, what's it connected to, and what do you want to learn from it?

 

[ruffdog]

Richard, you want to be careful here. There are several answers that are wrong - but I don't see any advice in the messages that will hurt you or the tractor.
Just like in politics, don't believe every explanations....

Tell me what happens with the ammeter when the key is on, the motor is NOT running, and the lights are on?

What I'm saying is do this: With the key on, and motor not running, turn on the lights. If everything is wired correctly then that's when the meter should swing to the left.
Assuming that your polarity is correct, then when the arrow swings to the left of zero that simply tells you that the battery is discharging. When the ammeter is to the right of zero then the alternator is doing its job of charging the battery.

Now if you wired it so that the polarity of the meter is backwards the meter will still work, it is just reversed. So in that case discharging is to the right, and charging to the left. That's all... the system is still working fine it's just that the meter reads backwards.

When the meter moves to the right of zero means that the battery is being charged. The farther it is from zero, the greater the charge or discharge it is measuring.

In a good charging system with motor running and lights on, the meter will still be to the right of zero. It will only move to the left of zero when the motor stops and the lights are still on.

Whether it is a generator or alternator system doesn't make any difference to the ammeter. Either system can also use a voltmeter to gain additional information as to how it is operating.

rScotty

^^^simple and proper explanation.....:drink:

 

[ruffdog]

When running, a little extra (over and above the system draw) is being put into the battery. That is why it should read pos when running. When not running and the lights are on, it should read neg because nothing is being sent from the charging system. Why have a ammeter? If you are running and it is reading neg, it means your charging system can't keep up with the demands and something is wrong. It is telling you to check it out before you are stranded out in the field.

 

[Richard]

Richard, you want to be careful here. There are several answers that are wrong - but I don't see any advice in the messages that will hurt you or the tractor.
Just like in politics, don't believe every explanations....

Tell me what happens with the ammeter when the key is on, the motor is NOT running, and the lights are on?

Batteries are out so can't double check. I've never paid much attention but if I had to guess, I'd say the needle stayed on zero or went slightly negative (I AM going to look when I get the batteries back in)

What I'm saying is do this: With the key on, and motor not running, turn on the lights. If everything is wired correctly then that's when the meter should swing to the left.
Assuming that your polarity is correct, then when the arrow swings to the left of zero that simply tells you that the battery is discharging. When the ammeter is to the right of zero then the alternator is doing its job of charging the battery.

Now if you wired it so that the polarity of the meter is backwards the meter will still work, it is just reversed. So in that case discharging is to the right, and charging to the left. That's all... the system is still working fine it's just that the meter reads backwards.

I presumed it was "ok" if polarity reversed.... with it always on the right side, that was what I was fearing and trying to ask/figure out. I presumed that it would ride on the left side of zero because the battery would always be short of a 'perfect' charge.... I'm concluding now that I was wrong and simply didn't know enough.

When the meter moves to the right of zero means that the battery is being charged. The farther it is from zero, the greater the charge or discharge it is measuring.

In a good charging system with motor running and lights on, the meter will still be to the right of zero. It will only move to the left of zero when the motor stops and the lights are still on.

Whether it is a generator or alternator system doesn't make any difference to the ammeter. Either system can also use a voltmeter to gain additional information as to how it is operating.

rScotty

Thanks to all, I understand a lot more now, how the meter works. (I've never been exposed to one in my life)

 

[BertZegers]

Thanks to all, I understand a lot more now, how the meter works. (I've never been exposed to one in my life)

We still do not know HOW you wired the amp meter in. Please inform us!

If you have put it in the charging circuit, it will never show a draw.

The Amp meter might be only showing large draws or gains, depending on its Amp range.

It is the same principle as if you hooked up a multi tester on Amp setting. (Most multi testers can not handle the tractor Amps and can/will be destroid )

 

[WranglerX]

A typical volt meter indicates zero and positive values. A negative voltage value would indicate reverse polarity, not a discharge condition.

Not quite, a voltmeter indicates electrical system condition.... IF voltage is below the approximate 12.8 -13-2 volts a battery normally has, it indicates generator/alternator is not keeping up with electrical system demand (ammeter would swing to negative [-] side) , if voltage is above the 12.8 to 13.2 volts of normal battery, something like 13.8 to 14.5(+) that means alternator/generator is supply enough current to properly sustain electrical requirement of system (ammeter swings to positive [+] side) .,.

Dale

 

[WranglerX]

Richard, you want to be careful here. There are several answers that are wrong - but I don't see any advice in the messages that will hurt you or the tractor.
Just like in politics, don't believe every explanations....

Tell me what happens with the ammeter when the key is on, the motor is NOT running, and the lights are on?

What I'm saying is do this: With the key on, and motor not running, turn on the lights. If everything is wired correctly then that's when the meter should swing to the left.
Assuming that your polarity is correct, then when the arrow swings to the left of zero that simply tells you that the battery is discharging. When the ammeter is to the right of zero then the alternator is doing its job of charging the battery.

Now if you wired it so that the polarity of the meter is backwards the meter will still work, it is just reversed. So in that case discharging is to the right, and charging to the left. That's all... the system is still working fine it's just that the meter reads backwards.

When the meter moves to the right of zero means that the battery is being charged. The farther it is from zero, the greater the charge or discharge it is measuring.

In a good charging system with motor running and lights on, the meter will still be to the right of zero. It will only move to the left of zero when the motor stops and the lights are still on.

Whether it is a generator or alternator system doesn't make any difference to the ammeter. Either system can also use a voltmeter to gain additional information as to how it is operating.

rScotty

Simplest and best explanation so far...

Dale

 

[RickB]

A typical volt meter indicates zero and positive values. A negative voltage value would indicate reverse polarity, not a discharge condition.

Not quite,

Dale

Take a minute and tell me what you think is wrong about my post. Please remember I did not mention an ammeter.

 

[WranglerX]

Take a minute and tell me what you think is wrong about my post. Please remember I did not mention an ammeter.

See message #16.... And it's all about reference point which in this case of float voltage of battery...

Dale

 

[BertZegers]

A typical volt meter indicates zero and positive values. A negative voltage value would indicate reverse polarity, not a discharge condition.

RickB is correct. The volt meter shows zero if no voltage is present. So the reading can be zero and anywhere between zero and the end of the scale on an analog meter.
Connected with reversed polarity will force the needle to the stop, but is not a negative voltage.

The digital volt meter will show a negative voltage only if the positive probe is on the negative and the negative probe is on the positive /U].