wiring and relays question....

[Gfretwell]

I said they can't be the "disconnecting means" but you can use them for the controls. In his case if the blower didn't stop when the gate was closed it wouldn't be life threatening. Personally I would use a 30a 2 pole snap switch in a regular device box (Home Depot) as my disconnect and an SSR the controller. You are not supposed to use the plug as a disconnect if the motor is over 1/8 hp but you don't have to look far in you shop to see an exception to that rule. You really only need one SSR if you have a "disconnect". hosfelt.com has a 50a SSR for $25 that switches with 3-32vdc at a few milliamps (any small DC wall wart would do). catalog #45-679

[Gfretwell]

Where do you shop? They are less than a buck at every net site I shop. Hosfelt has them from .15 to .75 each. I pay more than that for stainless steel screws.

[Robert Bonomi]

Try select 'relays' from the main menu page, then 'contactors' from that menu.

About 1/4 way down, there's a 24vac coil

240VAC double-pole single throw 'air conditioning' contactor, for $17.

half way down (in the 'medium contacteor' section, is a 25A 240v double-pole,

24VDC coil unit for $13

see also the "HVAC" list, from the main relays page.

I'd consider the 'Honeywell relay center' on the HVAC page as the power- supply. rip out the relays that are in it, and substutite the $17 one above. Voila! it's even in a code-compliant enclosure. :)

Or, you can probably get a "open frame' 24V transformer from Radio Shack for under $10. Would still have to do up an enclosure, etc. -- might save $10 when you're done.

[hex]

I never said you didn't indicate that SSR's must also be used in connection with a "disconnecting means" so don't get hostile. The reason I posted at all was to point out that SSR's have a problematic failure mode -- which is not a big deal for switching a DC.

Regardless of the presence of a disconnecting means, there are still some applications where SSR's are never allowed --- even for controls. As an example, some areas in national research labs dis-allow SSR's as control elements --- there are areas where there is potential radiation danger if the controls don't work.

hex

-30-

[Lewis Hartswick]

"Microswitch" is a very specific

NO! Microswitch Is a company that makes thousands of types of switches. ...lew... (who at one time bought $12,000.00 worth of one kind) :-)

[jduprie]

Thanks! this is exactly what I was looking for.

--JD

page,

[jduprie]

good idea... i had thought of it, but would prefer to use a single (simpler cheaper) relay, I'm just not finding the ones I want....

thanks