Small battery like cylinder on back of alternator?

[Droolguy]

Just pulled my passenger side alternator to replace it, I noticed there is a small battery like cylinder bolted to the back with a wire and ring running to one of the posts that is not on the replacement alternator.

Pic https://imgur.com/a/xyww5HW

If someone could identify what it is, and what it does, I would appreciate it.

I am at a loss to figure out how something connected with only one wire in a DC system even functions.

 

[NDT]

Noise suppression capacitor, put it back. Prevents the enemy from radio locating the vehicle from electrical noise transmission.

 

[Droolguy]

Thanks for the quick response.

 

[MarcusOReallyus]

I am at a loss to figure out how something connected with only one wire in a DC system even functions.

The case of the unit is the other electrical connection. This is very common with capacitors used in the automotive field.


Put it back, IF you think it's important to you to prevent the enemy from radio locating your vehicle from electrical noise transmission.

(But that's not what it's for. It's to keep your own electrical noise from interfering with you receiving radio transmissions on your military radio.)

If neither case applies to you (meaning, you don't have military radios), you can safely toss it. OR not. It won't hurt a thing, and you'll probably never know if it fails.

 

[DeadParrot]

Also good to have if you install an automotive AM/FM radio. Most civilian alternators have one installed on the inside out of sight. Guess the military wanted one on the outside for ease of replacement.