[larryccf]

I am putzing around building a tobacco shredder. Yeah, i'm a smoker and shred my own tobacco leaf - i don't grow it, just climbing the learning curve on rolling my own, then shredding unprocesed tobacco leaf was enough

I'm not that literate when it comes to things electrical - i started out in my employment life as an auto mechanic at a dealership back in the 60s, and am familiar with how relays work in general but they have always been 12V relays controlling a 12V circuit. I was actually hoping of using a honda starter relay to control a 120VAC solenoid but researching on the web, found that's not recommended.

The solenoid I want to use is 120V with a 26 watt current draw - below is the spec sheet

I can supply the relay with 12V DC, that's not an issue, (i was hoping to find a relay that was 120V AC on both circuits. I'm sure they exist but i couldn't find one - i did find a 12V relay that supports a 120V switching current. What i am hoping is that someone can confirm for me that the following relay is good to go for use with the solenoid above

Basically i'm an idiot when it comes to electrical stuff - i assume the "2A" switching current, if it does refer to the 120VAC switching voltage, that would mean my 26 watt draw is about 1/10th of the rated limit of the relay but would like to know before i spend $$ only to burn the solenoid or relay up.

the 2nd part of my question is, the relay indicates it's "normally open" or off. My shredder uses a rotating 10" diameter cast iron disc (what i call the cutting head) with 3 blades, one every 120 degrees.

The solenoid (push) will be operating a clamping foot or bar, that just as a blade approaches the cutting edge (think of a paper cutter), a sealed ball bearing, acting as a ground contact for the relay, will close the circuit and the relay will activate the clamping foot / bar. (to picture the ball bearing acting as a contact, picture one of those turn of the century "high wheel" bikes that had a 50" front wheel and a small 12" rear wheel - the bearing is the 12" wheel and it's in contact with the cutting head / wheel)

As the bearing will be in contact with the outer edge of the 10" cutting head, On the outer rim of the cutting head or disc, what i'm planning on doing is machining recesses for nylon strips that will isolate the grounding bearing when the clamping bar is not needed. THere's only 15 degrees or so where the clamping bar will be needed to hold or press the tobacco down while the blade is cutting, then the solenoid will release, and re-activate when the next blade approaches.

if the "normally open" relay is not going to work in that fashion, should i look for a relay is normally open? do those exist?
thanks in advance

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[T.Cruit]

I can't quite visualize how the tobacco grinder is supposed to work, but the relay you're asking about does exist. This is a screenshot from automation direct. Select whatever coil voltage you need. Also buy a relay socket. For the relay shown SQL08D is needed. Also these "ice-cube" relays have both Normally open and Normally closed contacts.

 

[larryccf]

thanks

this video should make it a lot easier to picture. The Teck 1 was a german design sold from the late 1880s to 1910/1920.

THey' re on ebay, so i grabbed one and it's actually a pretty decent design. Only thing wrong with it, it's deceivingly small. The feed chute or channel isn't but 2.125" wide and it can't handle thick slabs of tobacco (pressed into mold). Doing single leaves or so at a time, it's slow.

THe cutting head or wheel on the Teck 1 is almost 6" in diameter. I've increased the diameter to 10.25", the feed chute to 3.75" wide, and i've motorized it and changed the feed mechanism from that splined wood dowel to a belt feed.

 

[T.Cruit]

I'm a little concerned about "grounding bearing", also how fast is cutter going to spin? Bearings don't like to pass current. A limit switch with a roller might be another option.

 

[larryccf]

10" cutting head will be turning at 18 rpm - with a blade mounted every 120 degrees, that works out to one cut every 1+ seconds, or 3+ seconds for a complete single rpm

my plan is to recess nylon strips into the out edge of the cutting head, so they're flush with the OD of the cutting head. The strips would run for 105 degrees of the OD, then the bearing would roll onto the steel surface for the next 15 degrees, then back onto the next nylon strip - the nylon is just to act as an insulator so the wheel isn't making ground

can you explain how a limit switch would work and how would i rig it to work? - the above just seems so easy to dial in the stop/start of the solenoid activating & stopping