Where can I get a bunch of SPST and DPDT switches that will work with AC wiring, and can handle 5-10 amps and up to 18 volts AC ? I need some with spring-return-to-center-off and some without that “momentary” flip feature.
I’d be really appreciative of any specific suggestions for where I can get these switches. I know that in general “electonics surplus” or “electrical supply houses” or “auto parts stores” will have them, but that is toooooo general for me and I need some specifics. Searching the NAPA auto parts web site yields nothing. Searching Radio Shack does not yield the AC DPDT momentary flip switches that I need.
Mechanical switches are switches. The low voltage and relatively low current aren’t an issue for AC vrs DC. If the swiches you are looking at are rated for the intended use you should be fine. (Speciality “switches” like relays or solenoids are a different matter)/
I found this site, but it looks like I need to go to a distributor who might want to sell me 200 of what I need instead of the 6 I actually need. http://toggle-switches.carlingtech.com/index.asp
Any ideas for where the “little consumer” can go to get this stuff?
Also, what’s the difference between “quick-make, quick-break” switches and “slow-make, slow-break”??
Radio Shack switches rated for DC are sold for automotive use. They will work fine on AC. A switch rated for 3 amp 24 volt dc will also handle 3amp at 115 vac. Ac current is zero 120 times a second and this helps reduce the arcing when the contact opens.
I bought my toggles and momentary switches at Home Depot here in Canada. I didn’t shop around for best prices but thought $2-$5 a piece was reasonable enough. Since I was there buying other supplies for the layout it was more economical than driving 10 miles to save $.50 elsewhere.
It’s really not important whether the toggle is rated at AC or DC - for our purposes amps is amps. For most 3 rail circuits, a 5 amp rating is more than adequate. 3 amps could be marginal depending on the circuit. The current rating determines the size of the contactors in the switch. An insufficently rated switch (current-wise) may see the contacts weld or bend over time, rendering the switch not capable of or not reliable at switching. Voltage rating is generally not important at our voltages - less than 24. It becomes important for arc-over concerns at much higher voltages -110 and above.
Turning high current DC motors on/off is the worst case for a switch due to the inductive load of the motor causing arcing as the switch is making/breaking contact.
Can’t tell you about quick-make and slow-make other than what their names imply. Not that the differences in times matter in our application. I suspect it has to do with switching heavy DC inductive loads.
“Make-before-break” does matter in our applications. It means that a double (or multiple) throw switch has no truly “off” position. Sometimes this is an important feature. An example would be some of the command circuit boards in our locomotives that do not deal well with a complete loss of power. That’s why they have batteries to carry them over power disruptions. Another example would be the CW-80 which does not like to see zero load. Most of the time, however, we do not want “make-before-break”. Center-off toggles are inherently NOT “make-before-break”.
Thank you, thank you, thank you !!!
Over on the MTJ forum, someone provided a link to this company, which sells switches to the general public in batches as small as a single switch and as big as a thousand switches: www.mouser.com