switch terminology

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bruin_ale

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Looking at the selector switches on pioneerbreakers and getting confused about what some of the terminology really means.

For example, this switch:
http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-SS22PMA-3

It looks like there are 4 terminals - so with 2 NO contacts I understand that if the switch were turned left, it would close the left contacts and similar for the right. How about hooking up the third connection? I don't see a Common on these things is I guess what confuses me. I was thinking it'd be sort of like a 3 to 1 or like a single pole triple throw basically - but doesn't look like that. I know alot of you have used these exact switches, can anyone clarify?

Thanks
 
Never used these exact switches but it looks like it has 2 NO contact blocks so you can have two different power sources feeding the two different NO contacts if you like. Or you can use one power source and jumper from one NO contact to the other. There are 3 positions, left closes one contact, right closes the other contact, middle both contacts are open.
 
Okay, was wondering if that was how that one worked. I guess I'd have to add another contact block to that switch to get what I'm looking for. Right now it's more like DPST.

I guess if I were to add an NC/NO contact block I could get a three to one type switch.
Thanks, I think I get it now.


Another sort of related question, I'm not clear how the illuminated switches work (like the ones Ohio-ed used). Do you run a separate voltage across those to illuminate them, or does it illuminate when it is selecting something with the appropriate voltage across it?
 
just thought about the switch a little more.. if I add a NC/NC contact and add that to a 3 way selector - then wire both NC in series it'll only pass current when the switch is in the middle spot.
 
Maybe it would be better for you to explain what you are trying to do with this switch. This may make it easier for others to help you with your problem.

I'm not familiar with the illuminated switches that OhioEd uses but there are various types of switches that all illuminate differently. Some only illuminate when a position is selected (this would be powered by the same feed to that contact) and some are constantly on (these could be a separate power feed or jumpered to your contact(s) to power all of them.)
 
just thought about the switch a little more.. if I add a NC/NC contact and add that to a 3 way selector - then wire both NC in series it'll only pass current when the switch is in the middle spot.

Good on yah! Thats exactly how you would wire the middle position of the switch. to get all three positions you need 4 contact blocks, 2NO and 2NC.
 
Maybe it would be better for you to explain what you are trying to do with this switch. This may make it easier for others to help you with your problem.

I'm not familiar with the illuminated switches that OhioEd uses but there are various types of switches that all illuminate differently. Some only illuminate when a position is selected (this would be powered by the same feed to that contact) and some are constantly on (these could be a separate power feed or jumpered to your contact(s) to power all of them.)

I think I talked myself into the solution eventually, but just for clarification what I'm trying to do is get a 3 position switch to work where one of the positions isn't "OFF"

Basically, I plan to use it as an element select switch:

BK - Auto - HLT

Where auto is controlled by a BCS.
 
Good on yah! Thats exactly how you would wire the middle position of the switch. to get all three positions you need 4 contact blocks, 2NO and 2NC.

Thanks, it's funny how different this type of stuff is to my job as an electrical engineer. I work in semiconductor design, mostly digital logic - so it's really a whole different ball game. Alot of the concepts carry over which helps in understanding, but that's about it.
 
Thanks, it's funny how different this type of stuff is to my job as an electrical engineer. I work in semiconductor design, mostly digital logic - so it's really a whole different ball game. Alot of the concepts carry over which helps in understanding, but that's about it.

Yeah no kidding. The specialization requirements for EE's is such a double edge sword.

What you're describing is an HOA switch. Typically Left is Hand (Manual On) middle is off, and right is Auto (BCS). It's done that way so you are no more than one click away from off. In an emergency situation you may not want to go from Auto->Hand->Off. Say Auto isn't calling the device to turn on but there is wort leaking onto the element terminals, having to go to Hand would cause a dead short at a minimum.

Just some insight, it is your system at the end of the day ;)
 
This is just the select switch, there is (or will be) a separate switch for On - Off - Auto on the element itself.
 
bruin_ale said:
Thanks, it's funny how different this type of stuff is to my job as an electrical engineer. I work in semiconductor design, mostly digital logic - so it's really a whole different ball game. Alot of the concepts carry over which helps in understanding, but that's about it.

Don't worry you aren't the only EE that was tripped up by these industrial selectors. Only took 2-3 scratched out switch state diagrams/tables to figure out the center NC/NC jumpering. I am actually going to use 3way selectors with three stacked contact blocks. The third block will be another NC/NC that will be daisy chained to all selector switches and prevent system power-on if any pump or element isn't initially in the off position.
 
Don't worry you aren't the only EE that was tripped up by these industrial selectors. Only took 2-3 scratched out switch state diagrams/tables to figure out the center NC/NC jumpering. I am actually going to use 3way selectors with three stacked contact blocks. The third block will be another NC/NC that will be daisy chained to all selector switches and prevent system power-on if any pump or element isn't initially in the off position.

Do have a diagram or parts list for this? Sounds interesting...
 
I think I see what he's doing.

3 way selector switch:
http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-SS22PMA-3

NC/NC contacts:
http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-COBY2NC

Basically, all switches for pumps and elements would use the 3 position selector. The left and right position would be for on/auto or whatever - the middle position is Off.

if you add a NC/NC contact block to the bottom and wire them all in series (I'd put them in series with a momentary contact "power" button) - the thing will only start when all the switches are in the Off position. Cool idea, btw.
 
I think I see what he's doing.

3 way selector switch:
http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-SS22PMA-3

NC/NC contacts:
http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-COBY2NC

Basically, all switches for pumps and elements would use the 3 position selector. The left and right position would be for on/auto or whatever - the middle position is Off.

if you add a NC/NC contact block to the bottom and wire them all in series (I'd put them in series with a momentary contact "power" button) - the thing will only start when all the switches are in the Off position. Cool idea, btw.


Yeah, this was talked about in great length for Kal's control panel.
 
First a little background info and sneak peek of my control scheme (skip if you are only interested in my selector wiring). I am going for overkill here not because it is necessary but because I am enjoying every minute of the design process. My system is going to be a 4 vessel HERMS system that is all electric powered and at some point in the distant future most system aspects will have at least some level of automation to them.

A simple PC will be running the main system control routines which will interface to a 32bit micro board I am developing. The 32bit MCU will be providing all of the low level interfacing to switches, sensors, elements, valves etc. My control system is going to be separated into two enclosures. The first is the Human Machine Interface (HMI) and will contain the PC, touchscreen LCD, switches, indicators, 32bit mcu, low voltage power supplies, and other odds and ends. The second is the Interface Control Unit (ICU) which will house all of the 240VAC components such as the contactor, SSRs, power relays. The split design will allow me to tuck the ICU out of the way and enable the main 50A service to the brewery to be segregated from the control electronics in case of system failure.

Below are the beginning schematics of my HMI and ICU boxes (there are many components missing from these high level designs).
Start-StopRev0_4.PNG


ElementControlRev0_3.PNG

The first image shows the start/emergency stop circuit which has ties to the 3-way selectors for 3 heating elements and two pumps. Each element and pump will have auto-off-hand control (1). All control signals are actually input into the MCU and it directly controls the SSRs and pump motor drivers (not yet finalized and not shown). My 3-way selector switches are stacked with a pair of NO and two pairs of NC blocks. The HLT element implementation for example will provide a +5VDC signal to two MCU input pins when the switch is in the off position (SW will know off is selected). When in Auto mode the left NO is now closed and Din1 is grounded while Din2 is +5 so the SW will know auto is commanded (2). In addition either auto or hand will open either the left or right NC switches which in turn removes the ground input to a power relay (3) so that AC can flow from the SSR to the element. Din2 is grounded and Din1 is high when in manual. Manual mode will not necessarily mean 100% on as I can’t have all elements on at once or I would use more than 50A. The MCU will control the load to keep it at safe levels in this condition.

The start/stop circuit is similar to others that are floating around this board. All switches must be in the off position to complete the circuit when the NO momentarily closed start key is operated in order to energize the starter relay (4). The relay load output will be tied back into its coil input (5) through NC stop button. The relay output then powers a contactor (6) in the ICU which energizes the 50A service.

So at first glance, anything I messed up or am I missing something? This is still a work in progress and I am sorry for the length of this post. Part numbers are listed near the components if I have made a selection. Full quality schematics are in this pdf.
 
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