woodhead52 wrote:Hello Dusty, Ain't a happy ending great.
As you suggest, I am ordering a new switch.
I wonder why they ever bothered to use a switch to join the neutral wires instead of just crimping them together. There's probably a logical explanation, beyond what I can see, like wire control or something. At least having a double pole switch allowed for a fall back solution. Possibly just what SS thinking was well.
I can offer an educated guess on this. But first, a little background on switch operation is needed.
When switch contacts first "break" open, the load current does not stop immediately. Initially, the contact gap is tiny, and the source voltage causes the current to simply arc across the contacts. This arc ionizes the air, and so there is a local path across the contact gap where the air is much more conductive than normal. In AC applications, the switch will generally continue to arc even when the switch is fully open, until the AC source voltage passes through zero. Then the conductivity of the air gap returns to normal, and the source voltage is blocked beginning with the next half-cycle.
The very same switch will generally have two different voltage ratings. One for AC applications, and another for DC applications. The DC rating is much lower, because the size of the contact gap must extinguish the arc all by itself.
Assuming an AC application, the switch will have at least two different current ratings, depending on whether the load is resistive or inductive. The current rating is highest for a resistive load, because there is no stored energy in the load that must be removed.
An induction motor like in a (non-PowerPro) Shopsmith is, logically enough, quite inductive. So when you try to stop the current through the motor windings, it resists with all it's might, generating however much voltage is necessary in order to keep the current flowing, until the inductive energy is exhausted.
Now guess where all that inductive energy gets dissipated. Yep, right in the switch contacts. That's why switches are rated for lower current with an inductive load. Contacts do "wear out" over time from normal use, due to erosion of the contact material from the arcing. A good datasheet will have a curve showing expected contact life (in cycles) vs. load current for different loads.
So now,
finally, here is my guess for why SS connected both contacts in series. It spreads the inductive energy over two contacts instead of one, reducing the heat generation and contact erosion on each contact, and thereby extending the life of the switch.
Sorry for the long-winded reply, but you did ask.
