Explain a relay to me...

[Richard Vyse]

While at the PCS meet I mounted two 184's on the Criterion and removed the one in the center. I wired both beacons to the single power lead from the old beacon. My beacons will stay on for about 5 minutes before the delayed breaked kicks them off. I was told to install a relay but I have no idea what that is or how to do it.

Help.....

 

[Danny Ryder - Deceased - 1962 - 2021]

You didn't expect all the lights to work all together did you? Hehehe! May have to run separate wire for each but will leave this to someone more ambulance swavy than myself.:3_7_11v:

 

[Mike McDonald]

In order to win....

Richard: In order to win next year's Light & Siren Show hand's down..... you need to mount (3) "CJ's" on the roof @100 Watts Each, + a "Q" in between the tunnel's and a B&M behind the grille, pulling a trailer mounted gen set with two 8-D Cat Batteries for back-up..... and still hope the famous REEB Ambulance doesn't show up from wherever it's resting place is? MM

 

[Dwayne Brooks]

In your case a relay is an electrical device that uses a very small amount of voltage to start & stop something much bigger. For example we use relays alot at work, you can start a 480 volt AC 3-phase stamping press with a tiny "signal" of 24 volts DC. Relays are also used in cars, a horn relay converts a ground signal from your steering wheel to complete the 12 volt signal to your horns. There are several types of relays.
In your case a relay will not help, your problem is that you are pulling too many amps on one circuit now... two beacons are pulling more amps than the breaker is rated for. You need a breaker that is rated higher than the amps you're pulling to run 2 beacons, I recommend you go with a higher amp breaker & increase the size of your power wire going up to the beacons (more amps generates more heat & will melt the insulation off or cause it to become soft) or put them on seperate fused circuits.

 

[Jerry Jacobson]

In your case a relay is an electrical device that uses a very small amount of voltage to start & stop something much bigger. For example we use relays alot at work, you can start a 480 volt AC 3-phase stamping press with a tiny "signal" of 24 volts DC. Relays are also used in cars, a horn relay converts a ground signal from your steering wheel to complete the 12 volt signal to your horns. There are several types of relays.
In your case a relay will not help, your problem is that you are pulling too many amps on one circuit now... two beacons are pulling more amps than the breaker is rated for. You need a breaker that is rated higher than the amps you're pulling to run 2 beacons, I recommend you go with a higher amp breaker & increase the size of your power wire going up to the beacons (more amps generates more heat & will melt the insulation off or cause it to become soft) or put them on seperate fused circuits.

Dwayne is 100% correct. You won't get better advice.

 

[Paul Steinberg]

He needs to also increase the gauge of the wire that is supplying the the power to the beacons, and put them each on their own circuit and circuit breaker. If he increases the amperage of the circuit breaker without changing the size of the supply wire, the higher amperage breaker might not trip and it will damage the supply wire since it is carrying more current than it is rated for. Circuit breakers are designed to protect the wiring, not the appliance. Also, every time a circuit breaker trips, it is slowly degrading in its ability to trip again. This is why breakers eventually don't trip, and the electrical wiring meltdown will cause a fire. In this instance installing a relay to operate the lights isn't going to resolve the problem until each light is put onto a separate circuit. I have no idea how many additional lights he has added to the system without adding additional circuits, but if he has just added them to existing circuits, they too might be dangerously overloaded. To put it bluntly, if Richard doesn't understand electrical wiring and all the ramifications of piggy backing additional lights to existing circuits, then he should leave it to someone who does, or learn about it before proceeding. I would hate to see him loose his ambulance to an electrical fire as a result of improper wiring. Even if the wiring "melt down" didn't cause an outright fire, the time and work to rewire an entire ambulance would be a daunting task.

 

[James Maguire]

The purpose of the relay in this case is to switch both beacons with a single source...

You want a DPDT relay rated for the load you are carrying. The reader's digest version:

Take the power formerly going to the beacons - use that to power the coil on the relay

Run TWO new power feeds each one with its own fuse (or breaker) - each one will go to one pole of the relay and feed one of the beacons.

 

[William Ross]

Ditto

I agree with Paul. In the past I learned the hard way in regards to wiring and loads (and how to use a fire extinguisher). I finally sat down with my brother in law (an electrical engineer) and he expalined the ins and outs of circuit abuse. Simply put it's not as easy as just gettng the power to the appliance and having it work. You don't have to be an engineer to figure out these circuit problems, just realize that there are right and wrong ways to go about wiring a car and seek out advice from the right people. Also realize wirng is not trivial and a bad job can result in burning your car to the ground or the whole building if it's in a garage.

 

[Bruce Osborne]

In your case a relay is an electrical device that uses a very small amount of voltage to start & stop something much bigger. For example we use relays alot at work, you can start a 480 volt AC 3-phase stamping press with a tiny "signal" of 24 volts DC. Relays are also used in cars, a horn relay converts a ground signal from your steering wheel to complete the 12 volt signal to your horns. There are several types of relays.
In your case a relay will not help, your problem is that you are pulling too many amps on one circuit now... two beacons are pulling more amps than the breaker is rated for. You need a breaker that is rated higher than the amps you're pulling to run 2 beacons, I recommend you go with a higher amp breaker & increase the size of your power wire going up to the beacons (more amps generates more heat & will melt the insulation off or cause it to become soft) or put them on seperate fused circuits.

This is a very good description of a system, also look for resetable breakers for each circuit.

 

[Dwayne Brooks]

He needs to also increase the gauge of the wire that is supplying the the power to the beacons, and put them each on their own circuit and circuit breaker. If he increases the amperage of the circuit breaker without changing the size of the supply wire, the higher amperage breaker might not trip and it will damage the supply wire since it is carrying more current than it is rated for.

Ummmm, that's what I said...

You need a breaker that is rated higher than the amps you're pulling to run 2 beacons, I recommend you go with a higher amp breaker & increase the size of your power wire going up to the beacons (more amps generates more heat & will melt the insulation off or cause it to become soft) or put them on seperate fused circuits.

Richard will get it straightened out now, guess the dangers of overloading a circut & using too small gauge wire should have been stressed more from the beginning...

 

[Steve Lichtman]

I'm no electrical expert, but could he use two relays connected to the switch? Turn on the switch, which throws both relays, one for each beacon with it's own breaker on each circuit?

Larger diameter wire is good! Remember, you now have two motors and 8 bulbs to power.

This is why multiple beacons were installed at the factory, they did all this work ahead of time.

If he were like most of us, only turning on the beacons once or twice a year and only for a few minutes, he could get away with it the way it is. Richard is NOT like most of us in that respect!

 

[Todd Merrifield]

To be clear, JUST a relay isn't going to solve the problem, but one or two may be PART of the solution.

I picked up a great little book at the Goodguys show in Columbus about automotive wiring. You can find it here: (at the top of the page)

http://www.watsons-streetworks.com/wiring_accessories.html

It is well worth the $8.00 it costs, whether you know nothing about automotive electrical circuits or you just need a refresher. It is very simple and easy to understand, and it starts at square one and builds from there. I recommend it to ANYONE who isn't fully confident messing around with 12 volt circuits. It explains everything with pictures as well as text, and gets detailed enough that you will also understand things like remote door lock circuits.

As for Richards problem, the best solution has already been described (splitting the lights out to two circuits, each with their own wire and breaker/fuse) but that is a lot of work running extra wires. Until that can be done, it might be possible to wire the two lights in series with each other instead of in parallel and still use the same breaker and wire, but it might make one light turn slower than the other or light up more dim. It is not the ideal way to wire it, but it wouldn't hurt anything and it would work with the existing wire and breaker until Richard has time to take apart whatever needs to be taken apart to run the new wires.

To wire the two lights in series, you would:

connect the POSITIVE wire from the breaker to the POSITIVE wire of the first light,

then connect the NEGATIVE of the first light to the POSITIVE of the second light.

then connect the NEGATIVE of the second light to either chassis ground or to a wire that runs back to the battery (whatever wire was there as the negative when there was only one light).

When wired this way, you will see one of two things: Either both lights will run slower and dimmer than they did before, or one will run slower and dimmer than the other. The difference may be negligable enough that it could be left that way and it would look all right.

 

[Mike McDonald]

Kevin "O"

It's too bad Kevin O'Connell didn't have more time to stay and help you as he is considered the expert of all experts for wiring of lights and sirens.... on the West Coast at least! MM

 

[Rick Duffy]

KO problem solver!

It's too bad Kevin O'Connell didn't have more time to stay and help you as he is considered the expert of all experts for wiring of lights and sirens.... on the West Coast at least! MM

Yes... That's right Mike!

Kevin spent some quality time with me, helping me wire the Horn/Siren switch for the Q-1B that was original to the '64.

In so doing, he even took a layer of skin off his forearm, while running wires under the dash! He blamed it on old age... I blame it on too many sharp edges under there!

Hopefully, he's healed up by now... but the Q played marvelously during the 17 mile Code 3 ride to the Hudson Fireman's Museum and equally as well during the light and siren show!

Kevin is MOST knowledgable and was an excellent guest speaker at our banquet!

Onward and Upward!

Rick

 

[James Maguire]

I wouldn't wire the beacons in series... By putting the beacons in series, you are in effect connecting them to a 6 volt power source. While this won't matter much to the lights, I doubt the motors will like it very much. At best, they might just stall - at worst, they will overheat as they try to work harder with less voltage.

The reason I suggested using a DPDT relay rather than 2 relays is that I like to keep things simple - no need to add complexity where it isn't required.

My question is... just how much do these things draw??? I wouldn't expect just 2 beacons to overload a circuit. I am wondering if there aren't other loads on the circuit, or maybe a high resistance short somewhere.

 

[Todd Merrifield]

I wouldn't wire the beacons in series... By putting the beacons in series, you are in effect connecting them to a 6 volt power source. While this won't matter much to the lights, I doubt the motors will like it very much. At best, they might just stall - at worst, they will overheat as they try to work harder with less voltage.

Good point. It won't hurt the lights, running the motors slower might not be the best for them. I stand corrected....

 

[Steve Lichtman]

Richard's car was "born" with one beacon, and apparently it wants to stay with one beacon....

 

[John ED Renstrom]

I really can't understand why a simple thing can get so confusing. people you use the switch to trip the "relay". heavy wire from the hot side of the the 4 gage wire to the main power solenoid which is just behind the switch panel is were you draw the power from for the lights. the simple way to do it is with a head light relay. power from the switch trips the headlight relay that is grounded threw the case. way less the 10 amps to do this. the power side drawes off the hot wire coming up for the switch panel. when it closed it runs the 2, 4 bulb lights that are grounded threw the car body. sorry if that is to easy. for me it ain't rocket science it's the KISS principle. it's either a relay or you change out the 10 amp breaker for one big enough to handle the load of the 8 bulbs. that is providing the contacts in the switch are heavy enough to handle the current draw. cole-hearse will have a switch big enough but it might not fit the hole. a relay tucked up behind the panel is easy and a lot neater.

 

[Richard Vyse]

I really can't understand why a simple thing can get so confusing.

Now Ed, not everyone is as smart as you when is comes to these things. I usually can figure it out given enough time and advice. I have the same thoughts when it comes to embalming a body knowing raising an anterior tibialis is not as easy as raising the left brachial, but I can do it.

 

[John ED Renstrom]

if you think of wring as plumbing it gets much easier. size of the pipe to carry the volume at a given pressure is all you need. relays are control valves with a remote switch. solenoids are just bigger valves. which reminds me if your taping off the hot from the main power Solenoid do so from the draw side so that it will be dead if the master switch is off. be sure to put a fuse in the power side to at least a 25 i would think. I don't remember the formula for watts to amps. don't work with that enough to have it on top of my head. just remember there is one. sorry if I came off as a wise guy. didn't mean to. for me if you were putting a relay in line for the lights of course you would trip it with the light switch. that is what that switch is for. turning on the lights. but first run the numbers 4 30 watt bulbs draw how any amps. you do have the 30 watt bulbs don't you not the 60? if the lights and the motors draw less then 30 amps combined, then first try a 30 amp breaker in the holder . if it holds and the switch does not get to hot to touch then just go with that. just following the KISS principality the easy thing first before the hard thing.