I just bought a Furnas R327A forward...stop....reverse drum switch for the motor on my Lathe. I'm running a Leeson 115V single phase motor. I'm having a bit of trouble wiring the switch though. I've posted a pdf diagram here
to illustrate the wiring of the motor and what I've tried. The advice of anybody with any experience at this would be much appreciated.
That page cleared up alot. It appears I was just bipassing the start capacitor circut altogether in the off mode. Problem is my motor has thermal protection so it has 7 leads, not 6..... I could bipass it but I'd like to keep it if its possible to wire the switch with thermal protection. Any ideas here?
My computer doesn't handle some PDF's too good, and yours is one, so I can't help with a drawing review. I did want to mention to you, that even after you get it wired up and have the motor so it will start in "reverse", please note that single speed AC motors if running in one direction will not reverse unless they are brought to a stop first.
The thermal protection device has two leads, and is probably a Klixon-type which is capable of carrying the motor start/run current. In the event that the TP device isn't rated for the motor switching current, don't use it for an AC line voltage protection device. A TP device can be intended for controlling a relay coil, but most TP devices that are used in single phase AC motors are capable of carrying the motor current.
You treat one lead of the TP device as a line connection, and the other lead goes to the motor's line connection, (in series with the motor lead, the TP opens if the motor temperature reaches the TP cutout temp).
Be aware that TP devices are often the self-resetting type (typically, there is no external manual reset button.. push to reset), and the motor will be re-energized when the motor cools down to the TP reset temp.
It's gratifying to see that that work is still being used. I wrote it in 1985 when I had a disk problem and couldn't be up and around. Don't email me with questions though - I haven't had to use that information for years. Grant, were you the one that did the ASCI art work for the diagrams on the web site? That looks like it was a lot of work to get those lined up.