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  #61  
Old Fri 15 June 2007, 08:11
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Hope I got it right this time. Still prefer a neutral travelling to all the moving parts and next to the low-voltage circuits, rather than a live(hot). I have a bad habit of fiddling on low-voltage circuits forgetting that mains might be nearby:


Have I got it right this time, Mike's N & R ?
  #62  
Old Fri 15 June 2007, 09:07
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Gerald,

It looks good to me. L1 latches the contactor on when the N/O pushbutton is momentarily closed. The coil to the contactor stays latched as long as the main disconnect (door switch) is closed AND the N/C switches (E-Stop, limit, etc.) stay closed. L2 becomes active when its switch is closed. The N/C switches are all shielded with a drain wire that connects on one end only to system/chassis/earth ground.

-Mike
  #63  
Old Fri 15 June 2007, 10:39
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Thanks Mike (R).

I am going to be bold and upload a few schematics before the other Mike gets here.

America's:
115V SINGLE PHASE SUPPLY Changed later - do not use this diagram
230V / 115V SPLIT-PHASE SUPPLY Changed later - do not use this diagram

Non-America's
230V SINGLE PHASE SUPPLY Attachment 127 Changed later - do not use this diagram
380V THREE-PHASE SUPPLY Attachment 128 Changed later - do not use this diagram

The missing one is the American 3-phase supply, because I don't know for sure what voltages you speak of there.

Please remember that the title of this thread has always been Mains power wiring for discussion. . . . .
- Mains power is the high voltage stuff that can kill you, and
- for discussion means that there could be mistakes, and that I would really appreciate everyone's input before it becomes the recommended way.
  #64  
Old Fri 15 June 2007, 10:47
Marc Shlaes
Just call me: Marc
 
Cleveland, OH
United States of America
Send a message via Skype™ to Marc Shlaes
Gerald,

Once these schematics mature and are critiqued by the experts, it might be a good idea to pull them all together and place them in the downloads area. I would keep your disclaimer on each page though. Just a thought.

Marc
  #65  
Old Fri 15 June 2007, 10:57
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Marc, they are intended for the downloads section eventually and have been numbered accordingly. There won't be a disclaimer on those drawings per se because everyone read the user agreement before registering to download, didn't they?

Seriously though, there are a lot of things that can be dangerous when building this beast, and they are not all electrical. My blood ran cold the other day when I saw Kim's photo of a balanced steel beam with a tricycle next to it in his garage. Bandsawing and grinding are two other places of great concern.
  #66  
Old Fri 15 June 2007, 13:42
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
Hi Gerald,

The last was better, but at least in the US it is rare to see the neutral being switched and is possibly not to NEC code. It is also much, much easier to trace down open switches when you can put your meter between the wire and any available ground. I doctored your image in the venerable Paint program to show how I would wire it.

I included the fuse because I would prefer to pop a 1A (slo-blo) fuse if a wire shorted rather than blow holes in things waiting on a breaker to trip. Additionally, if the contactor coil shorted it lets out a lot less smoke as the shorts are rarely dead shorts, just partial winding shorts that create a lot of heat and smoke if not fused at a low enough value. Use a slo-blo type fuse due to inrush on the coil.

I also included an optional illuminated pushbutton (could be a separate lamp) to show that power was switched on. It can be helpful when trying to figure out why things won't start.

Keep up the good work!

Mike Nash
Attached Images
File Type: gif MechMate Control.gif (34.8 KB, 1066 views)
  #67  
Old Fri 15 June 2007, 14:17
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The fuse is a good idea, but what sort of package? (Solder to be avoided as far as possible).
  #68  
Old Fri 15 June 2007, 18:54
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Mike,

I'm just trying to understand the circuit. When the on/off pushbutton is closed, don't you have a short on the switch above L1 and below the coil?

Greg
  #69  
Old Fri 15 June 2007, 20:09
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
Hi Greg,

The picture is a little unclear mostly because it is shown pictorially. I've put a standard E-Stop type circuit below with an added Off pushbutton. The C1 contact is the "seal in" contact that does indeed close around the On pushbutton to keep the contactor (relay) coil energized.

Quote:
Originally Posted by Greg J View Post
Mike,

I'm just trying to understand the circuit. When the on/off pushbutton is closed, don't you have a short on the switch above L1 and below the coil?

Greg
Attached Images
File Type: gif Control.gif (2.8 KB, 1052 views)
  #70  
Old Fri 15 June 2007, 20:26
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Thanks Mike,

That helps, but I still don't get the seal in contact. Let me study it tonight and sleep on it. If it doesn't "click" in the morning, I'll ask another question.

Geeez, seal in contacts and short circuits .... you can guess what I'll dream about

Greg
  #71  
Old Fri 15 June 2007, 20:50
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
OK, I got it. Its a latching circuit. You are using a pushbutton and what keeps the circuits "closed" when the pushbotton is released (rhetorical question). The latching or seal in "leg" of the parellel part of the circuit completes the circuit. So I get my terminology correct, is it a "mini" relay?

Google "seal in" and contact and you come up with a great web site.
www.allaboutcircuits.com

Not too many better ways to spend a Friday night

Greg
  #72  
Old Fri 15 June 2007, 21:31
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Until yesterday I had never heard the term "seal in". And then you guys want to trust diagrams that I give you?

Thanks for the pro help Mike. The drawings will be revised. Yup, faultfinding a bunch of series switches on a Live circuit is a lot easier than on a Neutral circuit - I must stop forgetting that the "Disconnect" switch is there for when we want to work on ANY of the electrics/electronics.

A fuseholder terminal block is ideal for the fuse, but bad on the wallet. Oops they are priced on bulk batches of 20-50 pieces. Folk have mentioned that FactoryMation does sell smaller quantities.

These look a LOT better on price! Singles
  #73  
Old Fri 15 June 2007, 22:12
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Quote:
Originally Posted by Gerald D View Post
A fuseholder terminal block is ideal for the fuse, but bad on the wallet. Oops they are priced on bulk batches of 20-50 pieces. Folk have mentioned that FactoryMation does sell smaller quantities.

These look a LOT better on price! Singles
Gerald,

Better check the spec's a little closer. Dang, you just posted that one was bulk and the other was single. Your good.

I did notice, that the factormation "store" had better ratings (current/volts).

Greg
  #74  
Old Fri 15 June 2007, 22:17
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Greg, at the current or voltage level we are talking of here, the quality is not critical. Can buy purely on convenience/price.
  #75  
Old Fri 15 June 2007, 22:24
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Agreed. But, for a newbie like myself, the factorymation site had better spec sheets.

Please don't ask what I'll do with the other 19 parts

Have a good evening. There is a good ball game on the "xm".

Greg
  #76  
Old Fri 15 June 2007, 22:36
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
I think if you order FactoryMation by e-mail (not online) you can get smaller quantities.

(It is 6.36am here - the evening is long gone!)
  #77  
Old Sat 16 June 2007, 07:12
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Here we go again - extracted from this proposal: 1060130CA.pdf


May I use an "L" in the lamp?

Generally I don't like fuses. But in this case, I can't think of a more perfect application for a fuse. That loop going along all the E-Stops in series can be 20 meters [70 ft] long with about 10 joints, flexing as well, running tightly parallel to control signal cables, and exposed in about 3 control signal boxes - a tiny fuse is VERY cheap insurance!
  #78  
Old Sat 16 June 2007, 08:04
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
Quote:
Originally Posted by Gerald D View Post
May I use an "L" in the lamp?
The L is fine. It simply seems to be a convention to use the first letter of the lens color inside the figure. A was for amber in this case, though any color is fine. The circuit looks great.

One possibilty for inexpensive fuse holders are those that mount in holes in panels and have a cap. Many of these can use crimp on connectors. But if you don't have the terminals and tool, then it gets pricey again. But as I have seen on your grounding thread, you really need the crimp tool anyway. The other issue with those holders is that they work best with a D shaped hole to keep them from rotating. Having said all of that, there are also holders designed for one fuse that can be soldered or use the crimp on terminals.

http://rocky.digikey.com/WebLib/Coop...t%20Series.pdf

http://www.newark.com/jsp/Electrical...sp?sku=67K1780

http://www.newark.com/jsp/Electrical...sp?sku=67K2290
  #79  
Old Sat 16 June 2007, 08:45
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mike, I am very partial to DIN rail mounted components that are very common here and in Europe. I think this style at at $2 - $3 is just right. (For these fuses one has to decide if they are going to be 20x5mm or 1x1/4")

While I have your attention, how fussy are you guys about the "flow direction"(?) inside a panel. For example, would you accept the bottom terminals of a contactor connected to mains and the top connected to the consumer - ie. flowing up? We tend to frown on that. We seem to want the consumer at the bottom and the supply from the top - ie. a disconnect switch will still be live(hot) on the top terminals even after turning off. Your comments?
(With bottom-entry cables it seems to make more sense to attach the mains to the bottom of the disconnect?)
  #80  
Old Sat 16 June 2007, 11:10
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
Yeah, I looked at your links after I posted mine. I like those fuseholders too as long as you have end clamps or other devices to support them, such as the relay/contactor. Plus you have to buy some DIN rail.

Bottom feed is something I run into. I got bitten by it Thursday as a matter of fact. I had voltage on the bottom of the fuses and none across the fuses so they must be fine, right? They weren't and I lost about 20 minutes futzing around with other possibilities before I discovered the fuses were fed from the bottom. It can be much more convenient at times, but I think they out to be labeled as such if it is done.
  #81  
Old Sat 16 June 2007, 13:08
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
We used to mount the DIN (German Industry Standard) rails hard against the back panel, but then it was tricky to lay panel wires out the bottom of of one component and then to the top of the next component. Now we stand the DIN (Deutsche Industrie Norm) rail up on spacers so that we can pass the wires under the rail. Snag with this is that tracing the wires can lead to mistakes because they get hidden. (A dental mirror is useful for this tracing).

Here is a mix of top & bottom feed, even with the rail up on spacers. But I think that the flow is fairly logical. As you say, labelling and diagrams also help a lot. I just wanted your opinion if bottom feed might be against any codes?
  #82  
Old Sat 16 June 2007, 18:09
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
Quote:
Originally Posted by Gerald D View Post
I just wanted your opinion if bottom feed might be against any codes?
I don't think it is against any codes in the US. The one I ran into was a US made, UL approved, digital DC drive package built by Reliance Electric.
  #83  
Old Sat 16 June 2007, 20:43
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Hopefully the last question on the bottom/top issue: Would any laugh if I fed this contactor (as an example) from the bottom on the T1 T2 T3 terminals? I reckon that turning the contactor over for upside-down markings is a worse crime to commit.

  #84  
Old Sun 17 June 2007, 09:11
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
As far as bottom feeding a contactor, I'm not sure. The only example I found was another Reliance Electric design, but they had relabeled the terminals. I found this short discussion also but I don't have the NEC handbook.

http://forums.mikeholt.com/archive/i...p/t-62360.html

I also began to question the wisdom of switching the neutral. Again, there seems to be no definite rules against it I could find other than the mention below, and it may be referencing switching only the neutral. I don't remember it being something that is typically done in the US since the neutral is bonded to ground.

http://www.isa.org/Template.cfm?Sect...ontentID=40708
  #85  
Old Sun 17 June 2007, 10:18
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
On bottom feeding, thanks for finding that discussion, and let's just avoid it altogether. (I plan to make more graphical drawings of the components on the DIN rail and you have helped me tremendously with real industry feedback)

Switching of the neutral is something that Mike R also had big problems with, but he eventually relented when it was made clear that we only switch the neutral simultaneously with the Lives (Hots) on a single multipole switch or contactor. We never think of the Neutral as something that is connected to Ground (Earth). In fact, because we have lots of Ground Fault Protection, touching Neutral to Ground (Earth) causes a trip (fault). Look at all continental Europe 2-pin plugs for 230V - they can be inserted any way around.

Snag is, we sometimes find that an idiot swops Neutral & Hot (Live) in a distribution board upstream and we are never 100% sure which of the two wires is 230V above ground potential. Maybe something similar to the US 230V single-phase where BOTH wires are treated with equal respect.

Bottom line is that we prefer switching both wires, but only in a switch that forces them to be switched simultaneously. However, since I am going to end up producing circuits for the America's versus the non-America's, I can avoid neutral switching in the one case.
  #86  
Old Sun 17 June 2007, 11:22
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mike N, the simultaneous disconnecting of all Lives(Hots) and Neutral is equivalent to pulling the plug - what could be safer than that?
  #87  
Old Sun 17 June 2007, 15:40
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
Quote:
Originally Posted by Gerald D View Post
Mike N, the simultaneous disconnecting of all Lives(Hots) and Neutral is equivalent to pulling the plug - what could be safer than that?
Well, yes and no. One of the issues with E-Stops in general is all of the new safety regulations that go with them. Depending on the assessed level of hazard to life and limb, it can get very pricey to properly construct an E-Stop circuit. This is true in the US as well as Europe. Worst case involves redundant contactors, safety relays (very pricey), and two pole force guided E-Stop pushbuttons.

The problem with breaking the neutral is that you don't know that it or the hot, really did break. Welded contacts are a fact of life. If you are holding a plug in your hand you can visually (or tactiley if you are vision impaired) tell that that all circuits are indeed disconnected.
  #88  
Old Mon 18 June 2007, 09:29
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by Mike Nash View Post
. . . . Worst case involves redundant contactors, safety relays (very pricey), and two pole force guided E-Stop pushbuttons.

The problem with breaking the neutral is that you don't know that it or the hot, really did break. Welded contacts are a fact of life. If you are holding a plug in your hand you can visually (or tactiley if you are vision impaired) tell that that all circuits are indeed disconnected.
Mike, to the best of my knowledge, the Ensto multipole disconnect switches that I am promoting here, embody the principles of "safety relays" and "two-pole force guided E-Stop pushbuttons". These Ensto's are force-break or positive action switches - a single welded contact prevents the handle from turning and prevents any other pole from opening.
  #89  
Old Mon 18 June 2007, 11:04
Mike Nash
Just call me: Mike Nash
 
Bessemer, Alabama
United States of America
Quote:
Originally Posted by Gerald D View Post
Mike, to the best of my knowledge, the Ensto multipole disconnect switches that I am promoting here, embody the principles of "safety relays" and "two-pole force guided E-Stop pushbuttons". These Ensto's are force-break or positive action switches - a single welded contact prevents the handle from turning and prevents any other pole from opening.
That's good. And I was actually addressing the contactor as opposed to the disconnect switch. It's the reason redundant contactors are required in the applications that are considered to be more hazardous. I attended a three day "school" on safety devices and their use and application. All through the training it was repeatedly stressed that we were not to determine the hazards involved or suggest devices needed. The end user or equipment manufacturer was required to do that or they could contract a qualified (abundantly insured I'm sure) safety engineering firm to make the assessment as to what was required. My only intent is point out possible issues based on my expereince with equipment failures over the years.
  #90  
Old Mon 18 June 2007, 11:49
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mike your words have been very much appreciated. The readers keeping an eye on this thread must have noticed:

- how tricky this subject can get and some of the risks to be considered,

- that it is not a simple DIY project to be tackled lightly

- how unqualified I am to be the guide in this area
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