Hi all,
I've been trying to add a temp sensor on my dash so I don't have to look back or ask my family to tell me if the genset is running hot. We have an info panel installed on our cupboards but I can't see it while we travel. I bought this guage and I'm trying to hook it up to the same sensor my genset info panel uses on the engine. I get the correct reading on my info panel but nothing on the new guage. If I connect only the new one, I get the correct reading.
Any thoughts would help! ;)
Thanks!
Pat
That's not going to work like that. You can buy dual output senders that will operate two gauges. They are often used on boats. The gauges and sender must be properly matched.
easiest is to put a T into sensor hole and run two sensors..are you wired to sensors parallel or series ? Lin noticed you post while typing.what if he wired them in series would they only read 1/2 of actual?
Those are two great ideas guys! Thank you so much for your expertise.
Pat. ;D
Datcon makes a pair of gauges designed to run from a single sender (one output). That's what we use on our genny -- one gauge at the genny enclosure and one on the dash. Same with oil pressure.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
I have always ran 2 gauges of 1 sender from the generator like Sean never a problem for me
How about just using a video camera. Many yachts have just one set of mechanical gauges in the engine room with video cameras to watch from the bridge. Good Luck, TomC
Quote from: luvrbus on July 15, 2010, 08:40:03 PM
I have always ran 2 gauges of 1 sender from the generator like Sean never a problem for me
It depends on the type of gauge. Tachometers may work as they are just counting pulses. Resistance dependent gauges like pressure and temperature, even if they work, will not be accurate because the resistance is divided. There are both senders and gauges designed for dual positions.
In addition, the gauge must be matched to the sender as there are several different resistance types out there.
How about a switch to select the gauge you need at the time? Wire it to the control location you have now.
Centrix you will find out here you try your idea first then if doesn't work then you ask lol
Quote from: Don4107 on July 16, 2010, 08:13:44 AM
How about a switch to select the gauge you need at the time? Wire it to the control location you have now.
This is how I did it. I drilled out the drain plug for my differential and pipe threaded it for the sender thread. I used a sender identical to my engine coolant and connected it to a switch on the dash. When it is in the differential temp sensing posit I get a red led light over the gauge. This would work with a lot of sensors we use and would be reason enuf to change out sensors and meters to accommodate.....I did.
MORE importantly: While you are in there and mucking about and running wires and such consider this: Nobody is ever watching when the needle pegs. Gauges are not for anything but verification and seeing trends develop. Install "idiot type" sender units that switch on(make contact) when alarmed. That means the water temp alarm unit goes to ground when over temp is sensed and the oil pressure sw goes to ground when the oil pressure drops below acceptable limits. You can run these all in parallel and to a single red light AND A LOUD ALARM but install a "cut out switch so you don't get and alarm for low oil when starting. On that cutout posit have a large red light to alert you to the system being bypassed. Test it by switching on the engine power with the disable.
If you are running a 2 Stroke with two thermostats you should have a temp sensor and alarm for both heads.
Admittedly, I am sort of anal on this topic.
Good luck,
John
Quote from: JohnEd on July 16, 2010, 10:46:21 AM
... That means the water temp alarm unit goes to ground when over temp is sensed and the oil pressure sw goes to ground when the oil pressure drops below acceptable limits. ... run these ... to a ... LOUD ALARM ...
Actually, I disagree with all of this in the present situation (generator coolant temperature). Rather than using up a good coolant sender location for a sender for an alarm that should, by rights, never sound, you should use (or, more precisely, the generator manufacturer should have used) that location for a two-wire, normally closed sender wired into the "run" circuit. When the temperature reaches the set point, the contacts open and the generator immediately shuts down. A similar switch, with normally open contacts, is used for oil pressure; when the pressure drops below a set point, again the contacts open and the generator shuts down.
You need to use two-wire senders for this purpose, because you want the fail-safe shutdown circuit to be power-to-run (meaning any loss of power causes a shutdown). Most diesel generators include these common safety shutdowns as a matter of course.
A grounding sender for an alarm and light is a good idea for engines you can't allow to shut down inadvertently, such as the main engine. Many buses commonly came equipped with Kysor modules to do exactly what you described (gang several fault conditions into a single light and buzzer or bell).
I am presuming the the OP's generator has two coolant senders; one would be the shutdown as I just described, and the other would be the sender for the gauge. It is this latter sender which would get replaced with one made to drive a dual-gauge setup.
FWIW.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Sean,
I don't disagree with anything but your crit of me. Your info only augments and compliments what I said. All the systems, and mainly the older ones, didn't come with the level of sophistication that you mention. Not that they all couldn't be modified to utilize all of the circuits that you noted. We were talking about gauges for monitoring performance. Emergency shut down circuits are a different topic. I offered ideas on achieving that level of monitoring utilizing all of the extant equipment/gauges/senders in the current design and my advice was germane and possibly of use.
Lets look at this as three topics about the same equipment. Those topics would be:
1) Monitoring with remote sensors and indicators.
2) Alarming with visual and auditory devices
3) Emergency shut down
I was referring to topics 1 and 2 and you seem to have been into topic 3. I agree with you on what you said about equip protection auto shut down devices. I also don't see what I said about meters as in any way a repudiation of what you said. You have often seemed, to me at least, to come out of the chocks with a resounding "YOU ARE NOT CORRECT" and in this instance, as others I have noticed, you are not justified in saying that even in the technical sense. Sometimes you seem to be playing "gotcha". The game is actually "How do we create the best and most full advice for any situation". Not who did it or what degree(academic, not Fahrenheit) is at hand.
I would suggest you read DaleCarnegie but I suspect many before me have already done so. Certainly I could be faulted for not utilizing his sage advice in this particular instance but I feel driven to baser approaches and I am sure you have been spoken to in velvet tones that haven't apparently gotten through.
Take this as on topic and clarification and intended as completely positive in tone and message. :)
Your friend,
John
Quote from: JohnEd on July 16, 2010, 10:57:23 PM
I don't disagree with anything but your crit of me.
John, I did not intend to "criticize" you and I am sorry you read it that way.
Please go back and read my very first line:
"Actually, I disagree ..."That means just what it says: I disagree with the recommendation. Disagreement is not criticism. Later in the same post I agreed with you that this was a good idea for engines that can not be automatically shut down, for whatever reason.
I stand by my disagreement, on many grounds, principally human factors. I think it is a bad idea to have an alarm bell or warning light at the driver seat for a generator when, for the same effort to make such a circuit, a proper safety shutdown could be implemented. That's an opinion (different from yours, apparently), and I thought I was clear about that.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Sean,
Perhaps my sensativity to your "disagreement" stems from how highly I esteem you professional opinion. I was in a reactive frame of mind when I read and answered your post. Even at that I now think I over reacted and extend the apology you deserve. I'm sorry, Sean. :o :)
Back to bidness: What do you say to splitting this sort off topic up into the three subsets I proposed?
*
Actually, I disagree with all of this in the present situation (generator coolant temperature). Rather than using up a good coolant sender location for a sender for an alarm
For clarity, I never proposed giving up the temp sender hole for anything.....I think we can have our cake and eat it too. Just takes a smidgen of engineering, mostly.
I have always used a single wire sender where the sender was NO and went to ground. That design, one that predominates in the industry, is deficient in that a broken wire defeats the alarm. a ground, on the other hand, will alert you to the circuit failure. I incorporated a Bosh 30 amp relay(for overkill) into my circuit so I got the two wire system but only ran one wire into the engine bay.
Little emergency so I'llhave to finish later
Sean I intend on wiring my coach almost identical to yours and using your many informative articles, posts, pictures, drawings on your website, etc. as my instructions and plans. However, I really dont like the automatic shut down of anything (other then if I am going to blow up my engine because of overheating and even then I want the option to override that if need be). John's idea of the alarm and lights is right on as far as I am concerned because I only use the gages for mostly troubleshooting or monitering if I know there is a problem, otherwise I am just blissfully driving along happy as a lark but keeping a closer eye on my speedometer "especially" if I see a black and white
Quote from: happycamperbrat on July 20, 2010, 05:10:07 AM
... I really dont like the automatic shut down of anything ...
Well, generator manufacturers have been using safety shutdowns for years for good reason.
The day WILL come when you are running the generator out of sight and earshot of any sort of alarm, or out of reach of the kill switch. Perhaps you'll be sound asleep, with the air conditioner running. Or you'll be outside, gathering firewood, checking out the swimming hole, or even driving back to the park entrance to pay for your site. Maybe you'll be working on the roof with a power tool.
Generators are (and should be) designed to run unattended. By contrast, a main engine is far less likely to be running when you are out of the driver's seat and away from the kill switch. Even then, most heavy diesels have safety shutdowns, which must be deliberately over-ridden with a dead-man switch to keep the engine running.
If I turn the cooling fan off on my generator while it's under load, it will shut down within 30 seconds. The time between when an alarm could sound and the engine would be damaged would be even less -- maybe 15 seconds or so. To keep a generator safe with an alarm-only system, you'd have to be within 5-10 seconds of the kill switch at all times. For low oil pressure, you'd have even less time, perhaps a second at most.
I do not know of any reputable genset manufacturer that does not included these two basic shutdowns. But many of us are getting used generators that may have been subject to amateur modifications, and some folks are putting one together from component parts, and these safety shutdowns are a critical part of any generator that needs to be paid attention to.
FWIW.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Sorry, missed this one while I was off line (long story):
Quote from: JohnEd on July 18, 2010, 08:47:28 PM
... I now think I over reacted and extend the apology you deserve. ...
Not necessary, really. I recognize that this is a flat medium -- tone and inflection do not come across -- and it is all too easy to misinterpret the tone of written words. One of my faults is that I write in the technical style of an engineering manual, and I tend not to "hear" all the ways in which the inflection might be misconstrued.
Quote
... I have always used a single wire sender where the sender was NO and went to ground. That design, one that predominates in the industry, is deficient in that a broken wire defeats the alarm. a ground, on the other hand, will alert you to the circuit failure. I incorporated a Bosh 30 amp relay(for overkill) into my circuit so I got the two wire system but only ran one wire into the engine bay. ...
The reason why grounding-type senders should not be used for the safety shutdown circuit is that they can not be made fail-safe. By this I mean a loss of electrical power to the sender circuit or a broken wire should cause an immediate shutdown. You might be able to do this with an oil pressure switch, if you got one that was NO, and it was the final completion of the Run circuit. But a temperature switch is more problematic, because you now need to open the circuit in the middle. So you need at least one two-wire sender.
While I agree with you in principle that an alarm/light circuit is nice to have, in practice, the set-point of the alarm circuit would either have to be so far from the set-points of the safety shutdowns as to be a source of nuisance alarms, or else they'd be so close together that the delta between alarm and shutdown would be milliseconds, rending the alarm circuit useless.
The more important issue, though, is the limited placement of temperature senders. While oil pressure can simply be manifolded from the existing pressure sender port and will work fine, proper temperature senders actually protrude into the coolant flow. You can't simply extend an existing sender location with a tee and gang more than one sender, because they will not be getting the correct readings.
If your engine has a single temperature sender port, my advice would be to use that port for the safety shutdown sender, which will be two-wire NC. And if it has two ports, then the second one would be used for the gauge(s) that started this whole thread. If two gauges are needed, then a dual sender is called for, again because there is no good way to add another sender.
If two gauges are not needed, there are senders that have dual terminals, one for a gauge, and one for a grounding-type alarm circuit. These senders are commonly sold for applications where a simple idiot light is being replaced by a gauge/light combination, or where the user wants a gauge but the ECM requires the switch. This could be used to implement a tell-tale alarm, but, again, the setpoint would likely be so close to that of the safety as to be nearly useless.
I have never seen a sender that has both a two-wire NC switch as well as a gauge output. Nor have I ever seen a sender that has both a dual gauge output and a grounding switch. Not that those things could not exist, but the market would be very small, and these are mass-quantity items.
FWIW, and speaking as I was about "amateur modifications," when I got my bus the generator in it had been modified either by the PO or by the crappy outfit that converted it (long since defunct, for good reason) with a tee into which the original safety sender and a gauge sender had been threaded. As a consequence, neither sender was in the coolant flow and they were both getting lower temperature than actual. They had two different gauges with two senders which never agreed, and lord knows whether the shutdown switch could even have been effective if needed. To make matters worse, the shutdown mechanism they had cobbled together was power-to-shutdown, meaning that an electrical failure would prevent the generator from being shut down at all (whether with the control switch or by the safety shutdowns). We ended up putting all new safeties and gauges on it, rewiring everything, and putting a proper power-to-hold run solenoid in.
I hope that clarifies a bit more why I recommend focusing on a properly configured (and tested) safety shutdown system rather than adding a tell-tale alarm. Doing both correctly may be difficult if not impossible depending on engine configuration.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Brat,
I remember a lot of discussion about auto shutdown here. Must be an hour or so of speed reading. Lots of different opinions and a host of options.
We are kindred spirits on the issue of getting a gauge in front of you for everything. They are most applicable for troubleshooting and for spotting trends. To expand on that I think you need a gauge at the device and in the cockpit. Solely because you "troubleshoot" at the device, also. Back in the day, we Triumph pilots were well aware that there was no incident in recorded history of anyone looking at a gauge when it went to peg. We all installed idiot light senders and audibles. Race cars have this feature. What are we talking....water temp, oil pressure, volts and current. I don't think the alarm circuit is as justified at the gen cause you are in there. BUT, all of these are just the addition of a wire mainly. I wouldn't mess with the OEM protection circuits unless you are driven to that and even then I would get a lot of advice. I have no difficultywith imagining myself looking at the temp gauge and pondering ..."that is 10 degrees hotter than it usually runs....hummmmmm".
I don't like the auto shutdown except to protective from an idiot that is running my engine independent of my supervision. And you can dream up any circumstance you wish. An "over ride"....certainly...as long as it isn't labeled as such.
I remember hearing that the DDEC III had a auto shutdown AND a alarm that "sounded" a few degrees from shutdown. Also, that the shutdown came 20 seconds after the shutdown alarm, not the "caution-hi temp"alarm, sounded. That sounded a bit much to me but why not, if you have the computer and sensors do everything you can to make life safe and easy. Admittedly, I don't have all the facts, or even a portion, but that was discussed as a reality of some ECU or a possibility. And just what flexibility does Silver Leaf give you in the alarm dept?
If you get an alarm before b"terminal" temp is reached you can reduce speed and drop a ear to see if you an maintain. You get some time from a well designed system. Normal is 180 to 185 on a hill. 205(?) is getting to the damage temp and 212(?) equals cracked heads and other stuff. A couple thousand pounds of cast iron doesn't go up 8 degrees instantly or in 30 seconds so a alarm before shut down is use full and allows you time to take action and analyze the results. Whether the alarm is selected for 190 or 195 or 200 is a choice that will be driven by the normals for your particular system.
John