Buying buttons/switches on Ebay is pissing me off... can someone translate?

Hey guys!

I'm trying to buy a bunch of good industrial water/oil resistant buttons off of Ebay to use in my brewing control panel. Names like Allen-Bradley, Cutler Hammer, ABB, etc. Stuff that can live up to abuse. Stuff I'm used to seeing on plant floors.

Problem is the terminology. Some of it doesn't make sense to me and I'm familiar with terms like DPST (double pole/double throw), NO (normally open), NC (normally closed). Some of this stuff baffles me as they never seem to tell you how many poles or throws any of these switches have.

Example 1: NEW 22MM Selector Switch 3 Position Maintained 1NO/1NC
Ebay Link

It says it's a "SELECTOR SWITCH, 3 POSITION * MAINTAINED, 1 NO/1NC". Ok, it's switch with 3 positions but what's open/closed in each of the 3 positions? How can it have 1 NO contact and 1 NC contact? Under which circumstances? How many poles? Since it's 3 position is that 3-throw?


Example 2: PUSHBUTTON SELECTOR SWITCH AB ALLEN BRADLEY 800T-H2 XA
Ebay Link

Seems simple. It says it's a "2 P0SITION SELECTOR SWITCH. 1 NORMALLY OPEN AND 1 NORMALLY CLOSED CONTACT BLOCK". Ok, that makes sense, but why the word PUSHBUTTON in the title? How's that possible? It's a 2-position rotating switch. Or is it?


Example 3: Telemecanique Latching Select ON-OFF-ON Switch,EJ33
Ebay Link

It says it's a "Selector Switch. ON(left)-OFF(middle)-ON(right) LATCHING TYPE.". So it's 3 throw right? Or is it? But exactly how are the contacts wired? How am I supposed to know that? What's "Latching" mean? Does that mean "maintained"? (Ie: not momentary contact?)


Simple SPST switches (like example 2) are easy. Problem is that I'm looking for a DP3T (double pole, 3 throw) switch because I want to be able to be able to do the following in one switch so that only either my BK or HLT element is on at once in my 30A setup:

(1) Have BK PID send a control signal to BK SSR while HLT PID is cut off from HLT SSR.
(2) Both PIDs cut off from sending a signal to the PIDs (Switch center/off position).
(3) Have HLT PID send a control signal to HLT SSR while BK PID is cut off from BK SSR.

Forgetting Ebay for a moment, can anyone recommend any online stores that sell NEMA 4/12 style switches/buttons/pilot lights?

Kal

Sometimes those stores hire people to put things on ebay who know nothing about what they're selling. It sounds like you know exactly what you want....you should just send the seller a message or call them. Ebay can be a PITA, or you can score cool stuff on the cheap. I guess it's a two way street.

Hey Steve, thanks for the input. Emailing them all would be a full time job.

I don't think it's that they don't know what they're talking about as I'm noticing very similar terminology with most of the sales so I think there's something I'm missing. Maybe these industrial switches are incredibly simple inside so that multiple poles/throws aren't usually done or something so how they work can be described simply. I dunno.

I wish I had a place I could walk in to and play around and try these things out. Trying to do it online is wasting me hours and hours. Frustrating.

Kal

If I'm reading this correctly, you want a DPDT switch with an off or "neutral" center position.

EDIT:
Perhaps like this one:
http://cgi.ebay.com/30-Amp-DPDT-3-P...nectors_Switches_Wire?_trksid=p3286.m20.l1116

Hi Yuri!

Yes! That's exactly what I need. I didn't know you could buy double throw switches with an 'off' or 'neutral'. I was going to use the center pole as the off but this is better/simpler.

So the switch is exactly what I want, but I want an industrialized version like in the examples above. One that can be exposed to the elements.

This helps a lot though - thanks! I have extra ammo now.

Kal

Ok, so it really is something I'm missing. Take this 3-position switch (brand is Telemecanique):

Switch, 22mm, Selector OPERATOR, STD. LEVER, 3 Position, MAINT./MAINT./MAINT.


The official manufacturer's page is here.

So it has 3 positions and the positions are mainted (not spring-back momentary).
Here's the datasheet: http://www.alliedelec.com/Images/Products/Datasheets/BM/TELEMECANIQUE/226-0093.PDF

Here's the page from the official allied catalog: Allied Electronics - Catalog
(See figure 11 or 12).

Nowhere does it explain to me how many poles or throws it has. I need at least double pole double throw with a dead neutral (center). How is someone to know? What am I missing? This could be a single pole switch with 3 throws for all I know.

Kal

Edit Edit:

Ok this one... but not waterproof

http://www.fruitridgetools.com/stor...aspx?sfid=136763&i=153448356&mpid=8171&dfid=1

Leviton 1288 brown DPDT (double pole, double throw), center-off, maintained contact switch (manufactured by Pass & Seymour). Industrial Specification Grade, back and side wired, grounding, rated 30A 120/277VAC. Features include:

* Positive switching action with center-off position
* Large silver cadmium-oxide contacts for long life and to prevent sticking, welding and excessive pitting
* Clamp-type terminals accept up to #10 copper wire
* Full rated current capacity on fluorescent, tungsten and resistive loads; motor load capacity up to 80% switch current rating

From the catalog on your allied switch

10 Amp, 600 V Contact Ratings

I still don't know how many poles it is though (Says up to 9 circuits?)

kal said:

Ok, so it really is something I'm missing. Take this 3-position switch (brand is Telemecanique):

Switch, 22mm, Selector OPERATOR, STD. LEVER, 3 Position, MAINT./MAINT./MAINT.

The official manufacturer's page is here.

So it has 3 positions and the positions are mainted (not spring-back momentary).
Here's the datasheet: http://www.alliedelec.com/Images/Products/Datasheets/BM/TELEMECANIQUE/226-0093.PDF

Here's the page from the official allied catalog: Allied Electronics - Catalog
(See figure 11 or 12).

Nowhere does it explain to me how many poles or throws it has. I need at least double pole double throw with a dead neutral (center). How is someone to know? What am I missing? This could be a single pole switch with 3 throws for all I know.

Kal

Click to expand...

That is just the operator, you would need to buy the contacts separately. Many of the switches you are looking at are modular, you can put together nearly any combo you need.


I think this is the part you would need to complete that switch...

http://www.alliedelec.com/Search/Pr...4BZ103&R=2260124&SEARCH=2260124&DESC=ZB4BZ103

With the 3 position operator it should be on-off-on. I would recommend you call to confirm before ordering.


Example #3 looks to be the same thing.

conpewter said:

From the catalog on your allied switch

10 Amp, 600 V Contact Ratings

I still don't know how many poles it is though (Says up to 9 circuits?)

Click to expand...

If I understand correctly, Kal wants to switch the control between his PIDs & SSRs.

The one from fruitridge woud be perfect if he was switching the power side, overkill on the control side...

somecallmetim said:

That is just the operator, you would need to buy the contacts separately. Many of the switches you are looking at are modular, you can put together nearly any combo you need.

Click to expand...

BINGO! I've been looking at switches on the excellent AutomationDirect.com website and it dawned on me that everything's available separately: Operators and contacts. You build them as needed! *THAT* is the part that I was not understanding. Thanks for making that clear!

I think this is the part you would need to complete that switch...

Telemecanique - ZB4BZ103 - Allied Electronics

With the 3 position operator it should be on-off-on. I would recommend you call to confirm before ordering.

Click to expand...

Exactly. 2 N.O. contact blocks. (I think). Still not entirely sure how you define which of the 3 positions the 2 N.O. contact blocks "operate" in but it's probably pretty clear.

I'm really liking the prices at AutomationDirect.com however. $20 for an operator and a couple of contact blocks. Cheap. Simpler single contact block switches as low as $15. Why bother with ebay?

Thanks again.

Kal

somecallmetim said:

If I understand correctly, Kal wants to switch the control between his PIDs & SSRs.

The one from fruitridge woud be perfect if he was switching the power side, overkill on the control side...

Click to expand...

Correct. I will have 2 PIDs, each controlling an SSR. I want to ensure that only one element can be on at once since I'm building a 30A setup where each element draws 23A so only one can (and will) be on at once. I don't want to use two switches (one for each element) and assume that I'll never make a mistake and power both on at once. That's not the right way to build things (IMHO).

I'm looking at two options:

(1) Use a low voltage DPDT (center-off) switch to control which of the two SSR's get the low voltage control signal:
Specs/details

Pros: Cheap ($19), sealed/weatherproof, looks nice in a panel and I can get matching pilot lights, pushbuttons, legend plates, etc.
Cons: If one of the SSRs fails in the "on" state I might pop the breaker when I switch to the other element.


(2) Use a high current 30A DPDT (center-off) switch to control which of the elements gets the 240V circuit completed:


Pros: If one of the SSRs fails in the 'on' state, element will still remain off.
Cons: More expensive, not weatherproof (needs extra cover of some sort if even available), not as "purdy".

-------------------------

Is this "pro" really an issue? I really like the automationdirect.com buttons. Their prices are cheap! I could even 'upgrade' from 22mm to 30mm Cutler-Hammer controls like this lever-style rotating switch for about $6 more:

Selector switch, 30 mm metal, 3-position, maintained lever, 2 N.O.contacts


Purdy.


Kal

Well I'm not sure how SSRs will fail as I have not worked with them before. But could you wire in your indicator (pilot?) light on the other side of the SSR (So get a 240V led or something) and then you would know it failed when you switched to the neutral position (light would stay on).

It may all be moot since SSRs may be very reliable. Also if you get an oversized SSR it will be even less likely to fail (40 amp or more SSR and you only use ~22 amps through it)

Slightly off topic:

automationdirect.com sells nice aluminum legend plates for $2 with all sorts of ON, OFF, UP, DOWN labels already on them and blank ones like this too:



None of the pre-printed ones are of much use to brewers however (oddly enough there's none labelled "WORT PUMP").

What's the best way to get something printed on them? They're aluminum. Anyone know? Can a printing shop do something with a manual printer of some sort? I don't want to use a Sharpie pen. My handwriting writing sucks.

I have a Brother PTouch Label maker that is real nice.

BrotherUSA - Your source for home and office product information

conpewter said:

Well I'm not sure how SSRs will fail as I have not worked with them before. But could you wire in your indicator (pilot?) light on the other side of the SSR (So get a 240V led or something) and then you would know it failed when you switched to the neutral position (light would stay on).

Click to expand...

Yes, I plan on doing that. A positive indicator that the element is on. The switch that I'm looking at above is only to "allow" the element to be on. It doesn't mean it's necessarily on of course.

It may all be moot since SSRs may be very reliable. Also if you get an oversized SSR it will be even less likely to fail (40 amp or more SSR and you only use ~22 amps through it)

Click to expand...

Yup. I plan on a 40A SSR with heat sink to switch the 23A.

I think I'm being silly for worrying about it but I'm curious why nobody else seems to override their elements on the low voltage control side of the SSR's. It seems everyone uses 20-30A switches to control the 240V high current side.

Kal

First off on an SSR
Q What is the normal failure mode of SSRs and why?

A There are 2 failure modes; failed in the open state and failed in the closed state. Closed failures are the more common failure mode and this form of failure most often occurs due to overheating of the SSR which leads to an internal melting of components which end up as a closed circuit. The open failure is most often caused by a separation of solder joints due to extreme temperature changes over the life of the SSR.

Also says

The MTBF (Mean Time Between Failure) for our SSRs when properly installed and operated within the specifications is estimated to be between 20,000,000 and 400,000,000 hours.

HBControls_Information

kal said:

I think I'm being silly for worrying about it but I'm curious why nobody else seems to override their elements on the low voltage control side of the SSR's. It seems everyone uses 20-30A switches to control the 240V high current side.

Kal

Click to expand...

I'm using my 30 amp switch to turn my whole control panel on/off. At the moment I'm only going to have one PID/SSR set and I'll plug in the HLT at first, then after my sparge water is heated I'll turn off the panel, switch to the boil kettle plug and turn it back on, then I can (hopefully) use my PID in manual mode to control the boil. If a boil over is happening I can also quickly hit the switch that turns off the whole panel.

Thanks for the SSR info!

conpewter said:

... I'll plug in the HLT at first, then after my sparge water is heated I'll turn off the panel, switch to the boil kettle plug and turn it back on...

Click to expand...

Right! I forgot about this method that many people use too: Swapping kettle plugs. That's definitely a sure-fire way to make sure only one element is on at once. Personal choice, but I want to not have to do that myself. I'll have both the BK and HLT plugged in. Two PIDs/SSRs. (or maybe 3 if I can dream up some form of future expansion that may deem it like a RIMS setup).

Kal

Ok, I've got most of this figured out but some of this stuff confuses me.
Take this switch:

30MM 2 POS SEL SW MTD KNB 1 NO
(2 position, maintained with 1 normally open contact block)


Link: HT8JAH3AA5 Products

They sell the same switch that comes with 1 normally closed (NC) contact block instead of this normally open (NO) one. So what's the difference since it's a maintained operator (ie: the top part of the switch)? (Maintained means that when you switch it stays where you switch it).

So for this type of switch does 'NO contact block' mean that if you install it so that the tab is up/down, the switch is open and turning it right closes it?

And 'NC contact block' means that if you install it so that the tab is up/down, the switch is closed and turning it right opens it?

NO/NC is obvious with momentary switches but I'm not sure about with maintained switches since you're not gaining anything, unless it's important for the operator which way you should be turning the switch... as you can do the same thing with either one. Only difference is the direction you turn it (I think).

Kal

You can think of the contact blocks themselves as momentary(there is a spring in there), the operator can be maintained or momentary. If you are using a 2-pos. maintained operator you won't really need to worry about NO/NC unless you need to switch more than one thing on-off with the same switch.

Thanks Tim! That makes a lot of sense.

Kal

I'm happy to help & looking forward to seeing the build. Judging from you bar setup it will be sweet.

These things are simple when you get your hands on them...

Also a big thing for NO and NC is, Think Safety. properly wired E-STOPS should be setup with NC contacts. That way if they fail, they fail closed thus enabling the Emergency shutoff and not disabling it. It refers to the state of the contacts in a no power situation. If power goes away, do you want the contacts to be opened or closed? It makes a big difference especially in automation.

somecallmetim said:

I'm happy to help & looking forward to seeing the build. Judging from you bar setup it will be sweet.

Click to expand...

Thanks!

These things are simple when you get your hands on them...

Click to expand...

I know... If I could just pick them up and spend 10 seconds with them an a continuity tester/ohmmeter I'd be set.

So next question of the day: Push/pull (maintained) illuminated mushroom pushbuttons...

Pushbutton, 30 mm metal, push-pull, illuminated, green, 120 VAC/DC full voltage LED, mushroom operator, 1 N.O. contact


If you get one with 1 N.O. contactor like above would that mean that when it's pushed IN, it's N.O. and the light is off? (That's what I want). The PDF specs aren't clear.

I would assume that's how it works I would think. I want the light to be on when you pull it out to turn on the device as if you need to cut power you'd want to smack it in quick (for safety reasons). I'll use 2 for the 2 pumps: Pull out, light goes on, pump goes on. Push in, light goes off, pump is off.

I suppose I could call the shop, but it's more fun to bug you guys and it's early Saturday morning here.

I lied, one more question: For the less expensive 22mm units like this one (directly below) how exactly do you panel mount it?:

Specs/details

These things have what appears to be like 2 metal screws. But that doesn't make any sense. You can't screw it into place into the panel with those screws. The screws would stick out and be visible no matter which way you went. The specs (link above) just show the switch sort of 'hanging' in mid-air with half on one side of the panel and the other half on the other side. I don't get what holds it to the panel.

The higher end 30mm units have gaskets that tighten/clamp down from either side so it's obvious:



Kal

IrregularPulse said:

Also a big thing for NO and NC is, Think Safety. properly wired E-STOPS should be setup with NC contacts. That way if they fail, they fail closed thus enabling the Emergency shutoff and not disabling it. It refers to the state of the contacts in a no power situation. If power goes away, do you want the contacts to be opened or closed? It makes a big difference especially in automation.

Click to expand...

Makes sense! Everything so far I'm going to be buying is N.O. as far as switches go (assuming I'm getting this right).

Kal

kal said:

Pushbutton, 30 mm metal, push-pull, illuminated, green, 120 VAC/DC full voltage LED, mushroom operator, 1 N.O. contact

If you get one with 1 N.O. contactor like above would that mean that when it's pushed IN, it's N.O. and the light is off? (That's what I want). The PDF specs aren't clear.

Click to expand...

Yes a Normally Open is what you would want for the situation where you pull it out and the circuit is made, Smack it in to stop electricty. These are what are normally used in EStops like I mentioned above.

About the mounting of the others, hard to tell without holding one liek you mentioned.

kal said:

Makes sense! Everything so far I'm going to be buying is N.O. as far as switches go (assuming I'm getting this right).

Kal

Click to expand...

I think you got it, but using one each of these for the BK and HLT would still give you the possibility of having them on at the same time. Just give you a big smackable button to quickly turn one off.....if you noticed. but worst case they both came on, you'd just trip your breaker. Shut one off, reset it.
I think you ahd the idea going with a 3 position switch. NC - nothing - NC. That way you could not have them on at the same time unless the switch got over powered and welded contacts together, or failed mecahnically. Which is just a chance you take but very unlikely. Once again worst case, being breaker trips.

Kal; there's nothing wrong with stacking switches, you can control 20 NO/NC contacts. On that picture in post #11 they look like some type of import switch of low amperage. This for one PID switching to many temp probes, stir motors or SSRD control switching.
Check your area for electrical liquidators that purchase end of job electrical materials. There is one less than two miles away in town and they had service panel parts for a 40 year old panel. Priced right also. Check around. The tons of MCC panels with switches, lights and contactors into the steel dumpsters.
I couldn't save the world thinking I had years of time to collect before retiring. Besides later and newer controls. Snap, back failed me before I collected more than I collected. Check a electrical supply house not Home Depot or Ace Hardware with their little home use crap, plus they sell wire by the inch 5X what a supply house would charge especially at contractors cost.
Sorry I should not be answering with ideas as i'm just a "visitor" on this forum one HBT member stated about me.

IrregularPulse said:

Also a big thing for NO and NC is, Think Safety. properly wired E-STOPS should be setup with NC contacts. That way if they fail, they fail closed thus enabling the Emergency shutoff and not disabling it. It refers to the state of the contacts in a no power situation. If power goes away, do you want the contacts to be opened or closed? It makes a big difference especially in automation.

Click to expand...

You are right, if we were talking about a relay, but E-Stop buttons are NC. Like this one...

GCX1226-24L Products

The normal state of a button is out, so Kal needs NC contacts for his pumps. The lights are seperate from the contacts, he can wire them however he needs.

kal said:

Thanks!



I lied, one more question: For the less expensive 22mm units like this one (directly below) how exactly do you panel mount it?:

Specs/details

These things have what appears to be like 2 metal screws. But that doesn't make any sense. You can't screw it into place into the panel with those screws. The screws would stick out and be visible no matter which way you went. The specs (link above) just show the switch sort of 'hanging' in mid-air with half on one side of the panel and the other half on the other side. I don't get what holds it to the panel.

Kal

Click to expand...

The front button or switch turns a quarter turn and you can pull it free from the metal base. Then you slide it thru the hole, click it in the base, then tighten the screws against the back of the panel.

I just read this thread and feel stupid. I have NO clue what the hell ANY of this means. I'm going back to my ignorant hole ha ha

IrregularPulse said:

I think you ahd the idea going with a 3 position switch. NC - nothing - NC. That way you could not have them on at the same time unless the switch got over powered and welded contacts together, or failed mecahnically. Which is just a chance you take but very unlikely. Once again worst case, being breaker trips.

Click to expand...

That's the plan.

The only thing I don't like is that the elements will energized on one 240V at all times when the system is on. During cleaning at the end of the brew session I'd like to have both pumps running recirculating Oxyclean while I scrub things down and I'd like both elements to be 100% disconnected then.

If I used a high current 30A DPDT switch with dead center like the one mentioned above to switch on the power side instead of the low power side it would work. I just don't know where to find a nice panel mount version of one. I don't want to use the one that one that looks like a light switch.

Another idea to cut power to the control panel entirely and plug the two pumps in elsewhere. Probably the easiest/safest as I'll also have some 120V/15A GFI outlets on a separate circuit handy too. But again, I don't like the idea of unplugging/replugging stuff all the time.

Open to other ideas too.

Kal

somecallmetim said:

The front button or switch turns a quarter turn and you can pull it free from the metal base. Then you slide it thru the hole, click it in the base, then tighten the screws against the back of the panel.

Click to expand...

Aha! Thanks Tim. That makes sense. I get it now!

Kal

It's doubly confusing without a schematic. You might try an outfit like Mouser Electronics. They probably have exactly what you need somewhere in the listings.

Rotary Switches

I left out rotary switches for a reason because they can only control low currents unless you using them to only control the signals to different SSRD's.
To have a rotary switch that can handle the elements amperage your better
off getting a bank loan to afford such a big expensive units.
Sad part on industrial jobs units like that were pulled as complete MCC units and placed in scrap dumpsters. No time or intrest to strip what I needed as there were always other times to get these items I always thought. Like a "turd factory" many panels pulled and scrapped for the metal no time to snag what I wanted for my odd home use.
Many of lunch hour were spent pulling parts that other electricians thought I was nuts. Years later I have found a use for some of these items. I should of colected more before I got hurt. At least I can get contractors prices at my local electrical supply house. A big markup on electrical materials.