My Emergency Power Cutoff Setup

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edma194
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Re: My Emergency Power Cutoff Setup

Post by edma194 »

Majones1 wrote: Mon Jul 12, 2021 12:34 am The Emergency Stop Switch has two sets of contacts controlled by the “button”. Pins 1 & 2 are normally closed, and pins 3/4 are normally opened, and in this configuration only pins 1 & 2 are used, which controls the hot power lead. When you press the Emergency Stop Button, it mechanically trips the switch, opening the contacts between pins 1 & 2, thereby removing power from pin 23 on the On/Off Switch. If you lose source power, the Emergency Cutoff Switch electrically trips the normally closed contacts between pins 1 & 2 (I assume this is done magnetically).
Is there some purpose pins 3&4 being normally open? I've seen similar switches that have both poles open and close together for 2 phase circuits, and the same as you describe where the second switch closes when the stop button is pushed to activate an alarm.
Ed from Rhode Island

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Majones1
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Re: My Emergency Power Cutoff Setup

Post by Majones1 »

edma194 wrote: Mon Jul 12, 2021 2:58 pm Is there some purpose pins 3&4 being normally open? I've seen similar switches that have both poles open and close together for 2 phase circuits, and the same as you describe where the second switch closes when the stop button is pushed to activate an alarm.
In this Powertec switch there is no purpose for those pins as they are not connected to anything, but I guess in another application they could be used to either sound an alarm or light a remote indicator if you ran a separate low voltage circuit to the switch. I guess it would be more proper to say that in my use of this switch those pins have no use, and this is how their drawing shows it should be used, but others could actually put those pins to use if they wanted.
Marc Jones

Model 10ER (1952), s/n: 72883 (MickyD restored in 2009/10) / Variable Speed Changer / A-34 Jigsaw / Jointer-Shaper Fence
Mark 5 Model 500 (1955), s/n: 309828 (MickyD restored in 2008/09) / Magna Jigsaw Model 610, s/n 65001 / Yuba 11” Bandsaw Model 630, s/n 39807 / Magna Jointer Model 620, s/n 17792 (restored in 2021) / Magna 6” Belt Sander Model 640, s/n 13742 (to be restored)
Professional Planer Model M5082, s/n 003918
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JPG
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Re: My Emergency Power Cutoff Setup

Post by JPG »

From a controls standpoint, that switch is a form AB (double pole - one pole N/C - second pole N/O).
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
RFGuy
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Re: My Emergency Power Cutoff Setup

Post by RFGuy »

I do believe that the e-stop button (HY57B) is a DPST switch, so 3,4 are either the other hot wire for 240V circuits or can be the neutral connection for 120V circuits. Basing this on researching other applications that use the HY57B switch and how they wire it. The question is really when you press the e-stop do you expect the machinery to be fully disconnected (hot and neutral for 120V circuits) or is just disconnecting the hot side sufficient? IF one wanted to fully disconnect the load with the e-stop they should be able to wire the neutral to 3,4...of course ohm it out first to confirm what I am reporting here.

https://www.amazon.com/HY57B-Emergency- ... B07N56QDV2
📶RF Guy

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Majones1
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Re: My Emergency Power Cutoff Setup

Post by Majones1 »

RFGuy wrote: Mon Jul 12, 2021 6:25 pm I do believe that the e-stop button (HY57B) is a DPST switch, so 3,4 are either the other hot wire for 240V circuits or can be the neutral connection for 120V circuits. Basing this on researching other applications that use the HY57B switch and how they wire it. The question is really when you press the e-stop do you expect the machinery to be fully disconnected (hot and neutral for 120V circuits) or is just disconnecting the hot side sufficient? IF one wanted to fully disconnect the load with the e-stop they should be able to wire the neutral to 3,4...of course ohm it out first to confirm what I am reporting here.

https://www.amazon.com/HY57B-Emergency- ... B07N56QDV2

This switch you linked to is similar to what is included in the Powertec Emergency Cutoff Switch, but the details presented in the Amazon product do not clearly show whether pins 3/4 are NO or NC. The HY57B is actually constructed with two SPST switch modules that mount into the HY57B body, and the second switch module can optionally have either NO or NC contacts. If you look at the engineering drawing you can see where the two modules sit next to each other with a space between them (looking at the right hand profile, see the two modules sitting below the button). For clarity, see the Kalhorn images and description at the link noted below.
Basic Engineering drawing
Basic Engineering drawing
6E2F48CD-9B64-44C4-B41D-09B2B9DD21CD.jpeg (64.33 KiB) Viewed 1247 times
A very similar switch sold by Kahlhorn (manufactured by Klinger Born?), which looks exactly the same, shows how the SPST switch can optionally be paired with a second SPST switch module that can have either NO or NC contacts. They look so much alike that it makes me think that Klinger Born may be the manufacturer and Kedu rebrands them, or they both get them from the same Chinese manufacturer.

https://www.kahlhorn.com/emergency-shut ... :2533.html

Anyway, I can tell you that I saw the labeling on the switches and it clearly indicates that pins 1/2 contacts are NC and pins 3/4 contacts are NO.
Marc Jones

Model 10ER (1952), s/n: 72883 (MickyD restored in 2009/10) / Variable Speed Changer / A-34 Jigsaw / Jointer-Shaper Fence
Mark 5 Model 500 (1955), s/n: 309828 (MickyD restored in 2008/09) / Magna Jigsaw Model 610, s/n 65001 / Yuba 11” Bandsaw Model 630, s/n 39807 / Magna Jointer Model 620, s/n 17792 (restored in 2021) / Magna 6” Belt Sander Model 640, s/n 13742 (to be restored)
Professional Planer Model M5082, s/n 003918
DC3300 Dust Collector (circa 1998)
RFGuy
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Re: My Emergency Power Cutoff Setup

Post by RFGuy »

Majones1 wrote: Tue Jul 13, 2021 2:26 am This switch you linked to is similar to what is included in the Powertec Emergency Cutoff Switch, but the details presented in the Amazon product do not clearly show whether pins 3/4 are NO or NC. The HY57B is actually constructed with two SPST switch modules that mount into the HY57B body, and the second switch module can optionally have either NO or NC contacts.

Anyway, I can tell you that I saw the labeling on the switches and it clearly indicates that pins 1/2 contacts are NC and pins 3/4 contacts are NO.
IF the model number of the switch is indeed a KEDU HY57B, then the Amazon pics clearly show what looks like a DPST switch to me and this matches other schematics that I have seen for other products that use an HY57B showing it as a DPST in operation. Often in electrical schematics if a function is not used the terminals are either not labelled or shown as a N/C (no connect), when in reality there is still functionality there. It would be simple enough to check with an ohmeter (and the device disconnected from power), should you want to confirm or disprove it. What "labeling" is on the switch itself indicating them as NO? Picture?
Last edited by RFGuy on Tue Jul 13, 2021 3:19 pm, edited 1 time in total.
📶RF Guy

Mark V 520 (Bought New '98) | 4" jointer | 6" beltsander | 12" planer | bandsaw | router table | speed reducer | univ. tool rest
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Majones1
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Re: My Emergency Power Cutoff Setup

Post by Majones1 »

RFGuy wrote: Tue Jul 13, 2021 7:43 am It would be simple enough to check with an ohmeter (and the device disconnected from power), should you want to confirm or disprove it. What "labeling" is on the switch itself indicating them as NO? Picture?
Yes, it’s certainly simple enough to check, but I’ve been distracted with side projects that I now most want to work on the projects I’ve been putting these tools together for. It’s time to make sawdust and finish some walnut. With the last information I found on the Klinger Born Switch, I’m convinced those switches are modular and what I found in the Powertec device is exactly how I described it. Although it’s been 25 years since I worked in that industry, I do have 15 years working as an electronics technician (on the Close-in Weapon System, and 9 years as a tech rep for the Harpoon and Tomahawk Weapon Systems); I do understand simple electrical devices like switches a little bit. Maybe someone else who gets a new Powertec emergency cutoff switch can update us on what they find. It is inexpensive, and provides some decent electrical safety.
Marc Jones

Model 10ER (1952), s/n: 72883 (MickyD restored in 2009/10) / Variable Speed Changer / A-34 Jigsaw / Jointer-Shaper Fence
Mark 5 Model 500 (1955), s/n: 309828 (MickyD restored in 2008/09) / Magna Jigsaw Model 610, s/n 65001 / Yuba 11” Bandsaw Model 630, s/n 39807 / Magna Jointer Model 620, s/n 17792 (restored in 2021) / Magna 6” Belt Sander Model 640, s/n 13742 (to be restored)
Professional Planer Model M5082, s/n 003918
DC3300 Dust Collector (circa 1998)
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JPG
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Re: My Emergency Power Cutoff Setup

Post by JPG »

Adding to the 'confusion' is that It being an Emergency Shutoff switch, it needs 'N/C' contacts that close only when the switch is 'ready for disconnection'(equipment powered).

Also "NC" does indeed mean 'No Connection' on schematics.
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╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
RFGuy
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Re: My Emergency Power Cutoff Setup

Post by RFGuy »

So, this is all an academic discussion, but I was just trying to answer the one or two people on this thread that asked the question about this particular switch. I finally found it listed on eBay with pics of both sides of the switch. It clearly shows 1,2 as NC (normally closed) and 3,4 as NO (normally open), so JPG is right as always. ;)

Also, as JPG points out, there can be confusion because NC often means "no connect" on schematics as well, not to be confused with normally closed. Of course, the original point I was trying to make is that NC (no connect) on a schematic, switch, relay, etc. doesn't always mean you can't use it. Often a component has more functionality than is needed in a particular circuit and the design engineer chooses to mark it as no connect on the schematic to avoid confusion, excess current drain, etc from those pins being used. I have designed and used many IC's over the years and "NC" on the datasheet is often used to hide extra features, test only pins, etc., etc.
HY57B_1_2.jpg
HY57B_1_2.jpg (39.56 KiB) Viewed 1206 times
HY57B_3_4.jpg
HY57B_3_4.jpg (35.46 KiB) Viewed 1206 times
📶RF Guy

Mark V 520 (Bought New '98) | 4" jointer | 6" beltsander | 12" planer | bandsaw | router table | speed reducer | univ. tool rest
Porter Cable 12" Compound Miter Saw | Rikon 8" Low Speed Bench Grinder w/CBN wheels | Jessem Clear-Cut TS™ Stock Guides
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Majones1
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Re: My Emergency Power Cutoff Setup

Post by Majones1 »

Thank you guys for digging out the details. I understand about the confusion between NC and NC (Normally Closed vs. Not Connected), and it can be somewhat confusing (like some of my Siri corrected text above 😊). It is usually apparent which is meant by the location of the abbreviation, although maybe not always. They usually put Not Connected at the pins, or connecting points, and Normally Closed above, or in place of, the switch contacts. In the case of the Powertec implementation, it was in place of the symbol for the switch contacts.

As is typical with manufacturers of these devices, the Powertec switch I used looks more like the basic dimensional drawing I posted above. Compare the right profile in that drawing with the second image RFGuy posted immediately before this post. Notice the gap between the two switch modules in the drawing and the lack of a gap between the modules in RFGuy’s photo. This does not mean the entire switch is different, the two optional switch modules are the same but the body (or chassis?) of the switch that they plug into is different. The Kalhorn URL I listed above has more information on the modules, as well as the need to use Normally Closed contacts in an emergency cutoff switch.

It’s been quite some time since I’ve worked with safety circuits so it was fun to be refreshed. Besides wanting to get back to work on wood, part of my reluctance to reopen my Powertec switch to ring it out and get photos is tied to the fact that I kept the jumpers very short since there is little room inside the box, and I’m not sure I can even swing the switch around enough to get decent photos of the sides of the switch.

Anyway, thanks for helping get clarity on this. I am always amazed at the level of detail you all reach in analyzing problems, tools, devices, and ShopSmith histories. I know I have learned from them, and I hope I can someday follow your examples to the benefit of others.
Marc Jones

Model 10ER (1952), s/n: 72883 (MickyD restored in 2009/10) / Variable Speed Changer / A-34 Jigsaw / Jointer-Shaper Fence
Mark 5 Model 500 (1955), s/n: 309828 (MickyD restored in 2008/09) / Magna Jigsaw Model 610, s/n 65001 / Yuba 11” Bandsaw Model 630, s/n 39807 / Magna Jointer Model 620, s/n 17792 (restored in 2021) / Magna 6” Belt Sander Model 640, s/n 13742 (to be restored)
Professional Planer Model M5082, s/n 003918
DC3300 Dust Collector (circa 1998)
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