Remote Starter Solenoid and Battery Disconnect Contactor

[stevet903]

OK, if you want to go the solid state route, this might be what you are looking for:

http://www.perfectswitch.com/downloads/Relay%20Data%20Sheet%20v1p1.pdf

They make a number of other items that may be applicable to what you are designing - solid state circuit breakers for example - check out the Power-Gate section of their web site....

Steve

[rv_safetyman]

Folks, you are really bailing me out here.  I am coordinating your replies with my design person since some of this is over my head

He pointed out that JWallin's calculation of 3600 watts being 1/2 horsepower was off by a factor of 10 - should be 5 HP.  However, the wattage or amperage at 12 V is the main selection factor.

Today, I am going to try to make it through the huge number of relays on the page cited by Steve:

http://www.texasindustrialelectric.com/relays.asp

I saw at least one that was continuous duty and normally closed.  I think it was 150 amp capacity, which may be enough.  I am sure there are others on that page.

Steve, the perfect switch item looks really interesting.  I forwarded a copy to my electronic guru for his review.

You guys are such a big help!!!  The project is heating up and I really appreciate all of the great replies.

When everything settles down a bit, we may want to do a bit of brainstorming about how the selected components can be used to protect our buses.  The high current circuits in our buses present some significant potential hazards (consider that we could weld at least 1/2 material with 300 amps).  I, and I hope all of you, have proper size fuses on our house battery bank (mine is 400 amp), but I doubt many of us have protection on the chassis battery system.  Same is true of battery shut off switches.  I have one for my house battery bank, but not the high current chassis circuit.

Jim

[akbusguy2000]

Jim:  I have a manual battery disconnnect like the one seen here:

http://www.cooperindustries.com/content/public/en/bussmann/transportation/products/circuit_protection/series_15250_batterydisconnectswitch.html

It's mounted near the coach's 8-D batteries, works very well to kill all power when needed, and it will handle all the loads I've thrown at it when in the closed position, including starting.

If I were in the mood to improve it's functionality I'd consider adding remote controls - perhaps by marrying an appropriately sized double-acting air cylinder to its lever/handle, which could in turn be controlled mechanically or other options, such as solenoid valves, etc.

Modern techies might consider my approach primitive, but I have read enough on these boards to realize the most troublesome components in the modern bus might be electronic in nature.  And, if I were to flind myself in the throes of an electrical fire, I would be more likely to have a functioning air system.

ymv

tg
4106

[luvrbus]

Jim,just asking how do the Hybrid cars disconnect automatic with a problem they disconnect even when they sense moisture or heat

good luck

[TedsBUSted]

. . . Studies suggest that there are a lot of high current (primarily battery cable size) electrical fires in buses and trucks.

I would have to question those studies, sounds like fear selling or buck-passing to me.
In my opinion, a simple starter circuit, capable of drawing full battery current, installed in a  clean workman-like manner, seems to be one of the most trouble-free and reliable of all circuits.

Usually a well designed OE starter circuit will outlast the vehicle, and that's including cables, insulation, connections. Unnecessarily adding connections and contacts to a high current circuit is usually an invitation to problems. Although I do feel there's at least some peace of mind to be had with a simple manual main disconnect.

I'm not sure of the specifics of your non-bus application, but I'll mention that some weld contactors, and electric lift-truck contactors, are well within range of switching the currents you've mentioned, although most of these applications have gone to solid state switching.

I'll also mention that once a circuit has gone into some sort of fire-starting dead short, there will probably not be enough ampacity left to energize any sort of magnetic coil actuated switch. With that, I would think that  your emergency application may be better off to rely on a current-held, mechanical drop-out, type  contactor.

Ted

[thomasinnv]

Jim, just a thought here at a possible solution. When I worked construction, the elevator guys sometimes had to install a 'shunt trip breaker' on the elevator machine. Under normal conditions it acts like a regular circuit breaker in the on position, but in the event of fire a low voltage signal (usually 24v) is sent from the fire alarm panel to the shunt and trips it to the off position. Possibly you might be able to find something of the proper capacity to work in your situation.

[rv_safetyman]

Ted, as far as high current fire information, one of the best I have found is:

http://www.onnettomuustutkinta.fi/Satellite?blobtable=MungoBlobs&blobcol=urldata&SSURIapptype=BlobServer&SSURIcontainer=Default&SSURIsession=false&blobkey=id&blobheadervalue1=inline;%20filename=gvty79bpq89a.pdf&SSURIsscontext=Satellite%20Server&blobwhere=1284990324385&blobheadername1=Content-Disposition&ssbinary=true&blobheader=application/pdf

There were two studies done, one in 2000 and one in 2001.

At the trade shows, I used to hear some pretty good stories from folks visiting the booth.  Several talked about having mechanical work done and then having either a fire or a total electrical failure from the mechanic mis-routing the cables or damaging them by stepping on them or dropping something on them.

Clifford, I have been wondering about the hybrid cars or all electric cars as well.  We have a company here converting some hybrid cars to lithium ion batteries and each battery pack (perhaps half a loaf of bread size and maybe 1 of 100) must have a PC board that can shut that battery off.  However, there has to be some sort of final shut off.

Ted, your suggestion about forklift contactors might just be the ticket.  The customer is in a market that would relate very well to that technology.  I will have to do some research.

thomasinnv, interesting application.  I will do some research on that as well.

Jim

[buswarrior]

DING DING DING!!!

thread drift....

TedsBUSted wins the prize!

Usually a well designed OE starter circuit will outlast the vehicle, and that's including cables, insulation, connections.

Most of our coaches are BEYOND the considered life span of the vehicle.

All the more reason to seriously consider some high amperage fire starting, or a complete rejuvenation of the high amperage components, including the cabling.

Electrical fires are a HUGE concern for the front line coach companies today. There have been way too many coach fires in the last 15 years caused by electrical issues.

Fire suppression systems are pretty much standard fare on both coach and transit.

happy coaching!
buswarrior

[TedsBUSted]

DING DING DING!!!

thread drift....

TedsBUSted wins the prize! . . .

So what's the prize for drifting?
Maybe a Cole Hersee master disconnect switch?  

With most vehicles, battery disconnecting is old hat, that's why I was trying to reply to rv_safetyman's original  non-bus industrial question.  But quietly drifting away again, I'll mention that with late 50's and newer wiring, plain old insulation deterioration is usually not near the problem it used to be with earlier cloth insulation.  And now with one of my prize-winning drifts back towards the center line, I'll say that many vocational trucks  and most heavy equipment applications are  usually equipped.with a manual disconnect located near the batteries.

With some applications, an in-cab remote disconnect is used. Remote disconnects are often seen on firetrucks. Remote disconnects can be both direct acting and relay-type. However, with a remote disconnect the main feed to the starter is not switched and remains "hot" at all times.

As to remote switching of the main starter feed, this has been done too; usually in a series-parallel application. Delco-Remy at least used to build a very heavy  two-terminal solenoid switch also. Externally the cap and studs of this Delco switch appeared to be identical to the typical Delco starter-mounted solenoid switch and I'm guessing that the internal components were similar too. Not sure if these are still in production because I haven't seen one in a long time. Hey was that just a good drift or what?  

In closing, some combination of the above components would nearly completely isolate a coach's battery bank and maybe some also could be applied in rv_safetyman's industrial application. Be warned, today's electronics do not like the  spikes associated with heavy relays and their collapsing coils.

Ted

[luvrbus]

Delco still makes that part you can buy it from Texas Industrial those are sharp people why not let them design you a system.
Jim I have had good luck with those guys in a commercial service never sent a project to them they could not solve DC or AC or a combination.
I started using the owners of TIE back in the 70's when Wabco couldn't figure out their own design for the electronics on the scrapers they built also they solved problems on my LS 918 crane Link Belt couldn't.
I don't know they still do that work or just sell parts the 2 owners have to be way up years now  


good luck

[buswarrior]

oops, I put the thread drift sentence in the wrong place!

You get the prize for the "outlast the vehicle" line!

I think I'm the one that was sending the thread drifting.

thanks for your excellent detail!

happy coaching!
buswarrior