Had to replace the starter solenoid contacts this weekend. As luck would have it I had an extra set of the "heavy duty" ones on hand.

Can anyone explain why one contact wears more than the other? One of the old ones was completely worn thin and burned through and the other still looked like new. Thanks for your responses.

John (DH)

 

Simply put, direct current (DC) travels in one direction causing one side of an arc to burn more. So the when the power travels from the first contact to the plunger the plunger may burn but over a larger area. As the plunger has a much larger contact area the burning is less noticeable. When the power travels from the plunger to the second contact, the second contact gets burned. At least this is how I understand it.

 

Thanks for the reply Bill.

John (DH)