Hi Lynn,

Many thanks for your comments.

Good point, although the contacts are normally closed, and open when the motor over-runs. So the usual problem of poor contact wouldn't apply. However, it's possible that the contacts may have welded together.

I think that to fully protect the motor it needs a controller to limit the time that current is supplied to the motor, to a safe value. A nice little PIC project!

BTW I've recently had a problem with my central heating where a micro switch stuck in the ON position, leaving the boiler firing, when it should have been off. However, this was a normally open contact.

73 Clive G3CWV

Hitchin, North Hertfordshire, UK

On 16/10/2011 13:16, Lynn W. Deffenbaugh (Mr) wrote:

I'm not familiar with rotors, actually, but micro switches that aren't switched often (like only when you run the rotor to the stop, which I'm assuming most people try to avoid) kind of limit the effectiveness of "self-wiping" or "self-cleaning" contacts. I'm just comparing it mentally with my doorbell button that needs a bunch of "vigorous activations" (aka pounding on it) periodically to keep function on a "push once, ring" basis.

So, unless you make a habit of running the rotor to the stops, the switches may not function when/if they ARE needed.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32