Charging problem

[Jag]

Hello,

I have a machine with 24v system. Couple of weeks ago it stopped charging the batteries. Firstly I suspected a blown fuse, which was not the case. Then I turned my attention to the alternator. It has 3 leads (battery, feedback, excitation, 4th is ground). I got no reading from those except the Bat lead, which showed 24v. I concluded the alternator is not producing no current at all.

I suspected that the rectifier is finished, so I measured whether it puts out more AC than normal (more than 0.5v). The voltmeter reading was 53v AC! I was sure the alternator was finished, so I got a new one, but the described problems are still there.

When the engine is running, I get a reading only from the Bat lead: 24v DC and 53v AC. Now the most confusing part - when ignition is on (engine not running), it still shows 53v AC, how is that possible? I believe the DC reading is essentially coming from the batteries, but how the hell I get AC voltage when engine is shut off? How to troubleshoot this net of problems?

 

[Darkwood]

Welcome to the forum Jag

 

[Barry White]

can you supply the alternator type (make and model)
I suspect its simply not being excited so either a wire broken or a bulb blown are the common causes

 

[Jag]

can you supply the alternator type (make and model)
I suspect its simply not being excited so either a wire broken or a bulb blown are the common causes

Thank you for replying!

It's a Chinese product, useful info is hard to find, nevertheless its make and model: FAWDE JFWZ27P

I'll start preparing for tracking the excitation wire.

 

[Barry White]

When the ignition is on is there a charge indicator light (usually red with a battery display showing) is it lit up when ignition on but engine not running?

 

[Jag]

Mykey, it hasn't got a light.

 

[Jag]

Problem solved! Tracing the excitation wire led me to an unusual connection, which was not protected enough from elements, water got in and you can imagine the aftermath. I fixed it and everything is in working order again! Thank you Mykey for taking interest and pushing me in the right direction!

 

[telectrix]

nice result.