generator voltage output

[John Santee]

How do I check the voltage output on my 1949 Ferguson TO20?

 

[phil(va)]

Get a volt meter, or multi meter and put it on a low setting for dc volts, and test it across the battery terminals with the engine running. If it's six volt system, you should get about 7 volts on the meter if it's charging ok. Sometimes a digital meter jumps around and an analog meter is necessary, but usually a digital meter will read ok.

 

[John Santee]

That"s assuming the regulator is working properly. Is there a way to check voltage output at the generator while the tractor"s running?

 

[John Santee]

That's assuming the regulator is working properly. Is there a way to check voltage output at the generator while the tractor is running?

 

[phil(va)]

It's been awhile since I did this, and I may not be remembering correctly, but if memory serves, you can remove the field wire connection from the VR and ground it (which means the genny field is grounded) and then check the voltage at the battery and the VR is effectively out of the circuit, so you should see full genny output. Someone with more recent experience may jump in and correct me, but that's how I remember it. In practice, on these tractors, the genny and VR are such a team that they are usually evaluated together. However, I realize if you have a problem and have to either buy a VR or repair a genny it is good to know which one before you spend money.

 

[rvirgil_KS]

Assuming a Type A generator-regulator the above answers are on track.

To test the system:
Read the battery voltage with engine off.

Start engine and read battery voltage. It should rise at least 10%.

If voltage at battery does not rise, ground generator field. If this brings the voltage up the problem is in regulator side of voltage regulator or associated wiring/ground

If no rise in voltage, leave field grounded and jumper from generator armature to regulator BAT terminal. If this brings the battery voltage up the regulator cutout relay is faulty, if still no rise in battery voltage suspect the generator or system wiring.

The output from the generator comes off of the armature post.