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Author Topic: Hazard Lights  (Read 233 times)

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Offline mountg01

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Hazard Lights
« on: June 29, 2020, 05:29:23 PM »
Hi everyone - I bought a n gauge car with flashing 'hazard lights' I connected it to my Gaugemaster 12v accessory supply - the car flashed once and stopped. The car supplier says:
"train controller outputs have unregulated outputs and flashing LEDs, flickering LEDs and electronic modules need a smooth regulated supply.  Static LEDs are fine on a train controller up to a point, as they usually only give out half an amp for the 12v accessory output and adding too many LEDs will mean this will also stop working.
 
If you are planning on adding more LEDs, especially flashing, flickering or modules such as arc welders etc then you would be much better off using a totally separate 12v DC regulated power supply".
Can anyone translate please? Does this mean I've blown the hazard lights or should a gaugemester 12v accessory supply provide satisfactory voltage for a 12v accessory?

Offline themadhippy

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Re: Hazard Lights
« Reply #1 on: June 29, 2020, 05:56:07 PM »
The voltage on a   unregulated load varies with load,without a load ,or very low current load the output voltage can be higher than expected,start drawing a current and the voltage will decrease.A regulated supply will hold the voltage to its stated value,theoretically regardless of the load,however in reality they still have a minimum current were the voltage will fluctuate,but its so low its not normally a concern,and a maximum current limit were they'll shut down.
Don't fart before your arse is ready

Offline Nigel Cliffe

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Re: Hazard Lights
« Reply #2 on: June 30, 2020, 10:52:03 AM »
Can anyone translate please? Does this mean I've blown the hazard lights or should a gaugemester 12v accessory supply provide satisfactory voltage for a 12v accessory?

Can't say what's happened to your model car. 

Most (all?) Gaugemaster power supplies, with a 12v DC output, are a transformer and a rectifier.  What comes out is "unregulated 12v DC".   Its voltage varies with load (so may be a lot higher than 12v with low loads), and the DC has a 50Hz mains ripple on it (so its far from "smooth").    Transformers are heavy and quite expensive.   

A "regulated 12v DC" can be had from a modern "switched mode" power supply.  Those are the small power bricks (either plugs directly into wall, or brick with short mains lead) used to power many modern devices.   Almost all of those are regulated supplies.   You can tell easily from the wide input voltage range - if it works on anything from 100v to 240v as input, its going to be a regulated supply, whereas if its only 220-240v, it may be a transformer (now rare, but not unknown). 

So, your best power supply for such things, is an old laptop, TV, or charger, looking for one which puts out 12v.  Read the label on the power supply for voltage and the current it can deliver.   Or buying a new one.


- Nigel

Offline Bealman

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Re: Hazard Lights
« Reply #3 on: June 30, 2020, 11:10:30 AM »
To answer your question at the end of your post, the answer should be yes.

If a smoothed supply is necessary, the circut of the led unit should sort that.

I have used old train controllers as raw power supplies for years without problems.
Vision over visibility. Bono, U2.

Offline ntpntpntp

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Re: Hazard Lights
« Reply #4 on: June 30, 2020, 11:28:09 AM »
I recently tried an LED with integrated flashing circuitry, it was very fussy about the voltage and wouldn't flash properly outside of a limited range. 

I have more success with simple astable electronic circuits built from discrete components (or bought online if I'm feeling lazy), or better still I create PIC based driver modules so I can program the flash rate and effects myself.

I always use a voltage regulator module to control the voltage for accessories.  For my current project I've made sure each baseboard has a 12V and a 9V regulator available.
« Last Edit: June 30, 2020, 11:30:30 AM by ntpntpntp »
Nick.   2016 celebrating the 20th anniversary of "Königshafen" exhibition layout!

Offline mountg01

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Re: Hazard Lights
« Reply #5 on: June 30, 2020, 11:39:11 AM »
I contacted Gaugemaster and they agree that the 12v accessory outlet on standard controllers is 'unregulated' and therefor not suitable for flashing LEDs and that I need to buy one of their 'regulated' controllers -  they seem to think this is quite acceptable that their standard product is unsuitable for modern accessories - maybe it's time Gaugmeaster updated their products, I'm a bit upset

Offline Bealman

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Re: Hazard Lights
« Reply #6 on: June 30, 2020, 11:47:42 AM »
There is really no need to get upset about these controllers/units if you look at them as a source of power.

Indeed, the latest NGSJ describes a circuit to turn them into useful power sources!
Vision over visibility. Bono, U2.

Offline ntpntpntp

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Re: Hazard Lights
« Reply #7 on: June 30, 2020, 11:54:00 AM »
I use these little modules as fixed output voltage voltage regulators

https://www.ebay.co.uk/itm/LM7812-Three-terminal-Voltage-Regulator-Converter-Module-15-24V-to-12V/253544689502



There are loads of other designs on ebay. Just remember most of them come from China even if it says UK
« Last Edit: June 30, 2020, 11:56:15 AM by ntpntpntp »
Nick.   2016 celebrating the 20th anniversary of "Königshafen" exhibition layout!

Offline mountg01

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Re: Hazard Lights
« Reply #8 on: June 30, 2020, 12:03:33 PM »
 link=topic=50141.msg651583#msg651583 date=1593514440]
I use these little modules as fixed output voltage voltage regulators

There are loads of other designs on ebay. Just remember most of them come from China even if it says UK
[/quote]
thank you ntpntpntp - if that's all it needs to regulate the output I think GM should fit them as standard to their top of the range contollers - I paid nearly £200 thinking it would give me everything I need, now I must fit something minor like this to make it work :thankyousign:[quote author=ntpntpntp

Offline ntpntpntp

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Re: Hazard Lights
« Reply #9 on: June 30, 2020, 12:21:12 PM »
Which GM controller is it exactly?

Which N gauge car (have you got a link) ?

We don't know for sure that this is the reason why your flashing LED didn't work, we are just theorising.

Do you have a multimeter? Every railway modeller should have one.   Connect the flashing LED to the controlled  track output of a controller, and gently turn up the voltage whilst measuring with the meter (making sure you have the correct polarity for the LED also). See if it comes to life?
« Last Edit: June 30, 2020, 12:29:01 PM by ntpntpntp »
Nick.   2016 celebrating the 20th anniversary of "Königshafen" exhibition layout!

Offline mountg01

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Re: Hazard Lights
« Reply #10 on: June 30, 2020, 02:17:13 PM »
Which GM controller is it exactly?


Which N gauge car (have you got a link) ?


We don't know for sure that this is the reason why your flashing LED didn't work, we are just theorising.

Do you have a multimeter?
[/quote]

This is my controller:
Gaugemaster GM-GMC-Q Four Track Cased Controller
This is the car
https://www.layouts4u.net/n-scale-lighting/n-scale-illuminated-items/car-with-hazard-lights-n-scale
but now both GM & L4U say I have the wrong controller

Yes I have a meter, I'll try what you suggest and see if it works but

Offline Nigel Cliffe

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Re: Hazard Lights
« Reply #11 on: June 30, 2020, 02:51:39 PM »

Gaugemaster's DC controllers are ancient, well tested, solid designs.  But, they do what they do, which is the things needed by folks 40+ years ago when they were designed.   They're expensive because of what's in them; a lot of pieces of metal; metal box, metal transformers (two in the unit described), and so on.   And they're pretty bullet proof because its a solid design with few parts to fail.   But, being 40+ years old in design, and even for 40 years ago, a fairly basic design, the output of the 12v DC sockets is not "stable" in a modern sense, nor is it "smooth".   


The little module mentioned above also comes in a very similar "variable output" type, usually with a screwdriver adjuster of the output voltage.   Those might be useful as the output voltage can be fine-tuned.  I've used quite a few of the variable output types on projects over the years. 



A voltmeter will show the voltage, it's not likely to show the ripple, or stability of the voltage.     Yes, they are a tool most modellers will find very useful, but don't read too much into what they show you. 



- Nigel



Offline ntpntpntp

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Re: Hazard Lights
« Reply #12 on: June 30, 2020, 02:58:46 PM »
So the Gaugemaster controller is pretty typical of most controllers in having unregulated accessory outputs.  Might be interesting to check with your meter the actual voltage at the 12V DC terminals? 

I wouldn't say you've got the "wrong controller", it's the same sort of thing as many of us use.

The listing for the car does specify it needs a regulated supply, so maybe it's a bit more fussy then (say) general purpose LED street lights with resistors which can tolerate a bit of leeway in the voltage and would work fine with the DC outputs of your GM unit.  Notice the similarly priced car with head/tail lights *doesn't* mention needing a regulated supply.   

As I mentioned in a previous reply, I've made sure I'm driving my accessories via voltage regulators to ensure the voltage is controlled, which then helps with controlling the brightness of the lights and also protecting microprocessor-driven accessories.


« Last Edit: June 30, 2020, 03:40:39 PM by ntpntpntp »
Nick.   2016 celebrating the 20th anniversary of "Königshafen" exhibition layout!

Offline mountg01

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Re: Hazard Lights
« Reply #13 on: June 30, 2020, 05:45:51 PM »
thanks everyone - as suggested I have connected the little car to the variable (track) output (with a meter attached) and it doesn't work at any voltage - I also have a few of the headlight/taillight cars and they all work at 12v from the accessory port but VERY bright - connecting through the track supply I found the best 'brightness' was achieved for those (and then the twin street lights also purchased) was around just 6v. I have a spare 7.5v plug-in transformer - and a new variable voltage transformer I purchased to run the strings of fairy lights I'm using discreetly around the layout so I'll use something other than the GM controller and leave that just for my tracks and points. Layouts4U did say they would swap the dodgy car if I returned it so all's good
 :thankyousign:

Offline ntpntpntp

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Re: Hazard Lights
« Reply #14 on: June 30, 2020, 06:38:19 PM »
I also have a few of the headlight/taillight cars and they all work at 12v from the accessory port but VERY bright - connecting through the track supply I found the best 'brightness' was achieved for those (and then the twin street lights also purchased) was around just 6v.
That doesn't surprise me at all, I usually run LEDs at far less than the "typical" current.  You're doing the right thing by trying a variable supply and find what looks right for your purposes. 

Techie note:  Just keep in the back of your mind that LEDs are actually current driven devices not voltage driven, and what you're really doing is adjusting the voltage across the series resistor of the LED and thus affecting the current flow. You must always use a current limiting series resistor with LEDs.

Quote
Layouts4U did say they would swap the dodgy car if I returned it so all's good
That's good.

They don't cost much, for example the head/tail light cars are all over ebay at 10 pieces for £7 ish from China

https://www.ebay.co.uk/itm/10Pcs-Flaring-Light-Painted-Model-Cars-with-Wires-N-1-150-Building-Train-Layout/193463713264

I've not seen the cars with hazards on ebay but no doubt they are out there

« Last Edit: June 30, 2020, 06:40:24 PM by ntpntpntp »
Nick.   2016 celebrating the 20th anniversary of "Königshafen" exhibition layout!

 

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