regulator problems and questions dt400

[twinrock]

So checked the Voltage out put today on the dt and out put was like 30v !! At idle,!. I had a spare regulator off a dt 125 this brought it down to 6v how evr regulator was very hot..it was much smaller in size with no cooling fins on it, .. when the bike was rev-ed voltaged increased to 50v , without the regulator on.. surely thats not right.. I would have imagined some where around 10v max.. I dont want to run it with the working regulator as im scared il burn it out then burn out lights ect..any help would be great thanks

[pokey]

It will be similar to the suzuki system and sounds like they are stuffed and not rectifying or your measuring incorrectly
Retrieved from "http://suzukits.informe.com/wiki/view/Voltage_Regulator_%28explained%29"


Voltage Regulator
A voltage regulator, or VREG is designed to smooth out the DC sine wave created by the rectifier. The VREG is wired is series, connecting the Rectifier to the system. In order to fully understand it's function, you must understand half-wave rectification.


1 Half-wave rectification
2 Voltage regulation
3 Why Regulate Voltage?
4 diagnostic purposes of this article
Half-wave rectification



The rectifier on the TS,TC, and TM bikes are all Single diode, half-wave rectifiers. This means that the rectifier simply allows positive current to pass and blocks negative current to the positive line. This process causes the the positive line to pulse, at the same speed as the AC alternated. Which, in a magneto system, is the engine speed.
Half-wave rectifier

 Voltage regulation
Voltage Regulation is the process of maintaining a steady output voltage irrespective of the input voltage. The faster the engine/generator is turned, the greater the voltage that is produced. A regulator helps to maintain a steady voltage for the electrical system.
Typically linear voltage regulators dissipate the additional power, this can cause heat within the device, hence, many units are supplied with heatsinks or are fastened to some metal part of the bike to dissipate heat.
 Why Regulate Voltage?
Without a steady voltage within the electrical system, lights and other electrical items would be subject to the varying voltage generated by the generator. As the generator/engine speed increases the voltage increases, increasing light brightness and often blowing bulbs.
It is worth noting that on many bikes, battery charging is controlled by other means.
diagnostic purposes of this article
Ultimately, on this system the voltage regulator is not strictly necessary. Because the magneto only puts out enough voltage to run the system, the VREG does not need to reduce it. At the same time, the VREG only allows the bulbs to 'burn' brighter and the battery to charge more quickly. So if you are diagnosing a system in which the bulbs are not receiving power, as long as the VREG passes voltage (even if it is not regulating it) it is not the cause of the failure.

Retrieved from "http://suzukits.informe.com/wiki/view/Voltage_Regulator_%28explained%29"

[twinrock]

Yeah I understand the function and how they work  but my question is still this..how hot should I expect it to get, like I stated the one that works sits nicely at 6 v how ever just gets quite hot..the one that doesnt work, the original one on the bike  pumps out up to 50v when revs are raised, is this typical of a bad regulator or is thre something else at play.maybe stator related as I have had faulty regulators before  but they still did not let the bike generate that kind of voltage..i can only asume its the reg as its dc voltage

[OverTheHill]

I'll put my oar in & you can pick bits out if useful. On my old 360 yam [talking RT1] i used to run a 12volt quarts halogen [big round xj650 light by memory] & ran it unregulated & never blew it but damn near melt holes in the tar seal. Apart from that [if 'not' running a battery to soak of the excess charge] run a finned DT175 [common yam reg] hooked to the tail light wire so it's there only when lights 'on' & regulating everything from instrument lights right through. that way it's only in use when lights 'on'. Of course--what to do with the stop light bulb which misses out that way. [talking 6 volt DT type regulator by the way with std 6 volt bulbs]. If you have the battery charged through the rectifier then that should soak of the excess but run the regulator as a bulb saver incase one headlight filament blows & takes the lot with it--hate that. Yam's used to have more than one wire where you could increase or decrease the voltage to the rectifier & alter the battery charge rate with lights 'off' but if this is still the case on your 400 you might be able to utilise these wires to vary voltage to the lights only. I'm 10 years behind your 400 thinking back to my 360 but nothing much changes in that area despite cdi ign. [i think!!]. Probably contradicted myself in the story above but pick through it. Good luck.

[twinrock]

Hey thanks for that.. yeah I should have a 175 one some where ,the dt100 one I have is very small no fins relys totaly on bike frame for heat sink..
..I have a dt200l one but it has 4 wires red, white, black and yellow, as told in another post using this could then give me the option of 12v  how ever which wire goes where?  Im currently using a step up modulater to be able to run 12v led tail light works perfectly.. problem  is if the reg fails it will and has fried the modual..a $30 part.. ifthe 12v reg works but ever fails u fry the leds which are not replacable. Have to buy another complete tail light..a draw back of leds in this case..

[twinrock]

Ok..I think I have a handle on this now..the prob was I did not realise that the batt also acts as a regulator sucking current..I was measuring the voltage across the batt leads not the batt itself..this is what I normally do with any "modern" 12v bike..as a result the bike was getting huge voltage soon as u conect the batt it sits at 6v with out the regulator getting hot...my fault and miss u derstanding .how ever I measured the  voltage on the head light which runs on its own direct off the engine it was at 12v AC at the globe , now that will blow a standard 6v globe almost instantly I just put a 12v globe in i.which is what "overthehill" was talking about however surely this cant be factory..could I now put a 12 regulator just on the head light...? Remember this will be a regular road regoed bike..so best, steadiest lighting as possible would be the best result

[OverTheHill]

hmmm, i've probably confused things enough--i know what i know but beyond that i'm a bit lost. But. you'll probably find the lighting coil has a few different wires coming off it. One will be direct lighting to the head/tail/& instrument lights & others will be one for charging & maybe an option for higher daytime charging. If you're measuring voltage across the headlight wires minus the bulb try it again with the bulb in place & the resistance of the bulb should sort it out. Think they run a 35 watt headlight so that combined with instrument & tail bulb might leave it reading ok with revs on. That's with battery hooked up & rectifier etc. Anyway, getting out of my expertise [lack of]. Would it charge enough to keep up with running a small 12 volt battery & run all the lights off it [battery] & have no more bulb issues. Or then again if that doesn't work, just do the same with the 6 volt battery as you know the charging will keep up when reved. More to think about. Cheers O.T.H
ps, i have a couple of resistors [suzuki & yamaha] not what you need but think they were purely to soak up the excess voltage on some scooters where you could run with the tail light & instruments on but headlight off & this resistor soaked up equal to the missing headlight bulb then got bypassed with headlight on--anyway, getting off track again.

[twinrock]

Now dts in my experience ,175s,200s and now 400 have 2 lighting coils one for tail light  indicators and horn, and one just for head light that only comes on when bike is running and runs straight unregulated from the motor the other, tail horn indicators run via batt I have since learned that the so called regulater is nothing more then a diode which simply acts as a altinator switching AC to DC then the batt is the regulator. How ever the head light  On my bike is putting out up to 12v ..I originally just fitted the 6v globe and ran the engine and it blew the bulb in a few seconds.. thats when I measured the voltage to find it was running up to 12v..Now my thinking now is maybe on the 400 the tail light is also to be run on the same coil as the main light this would prob bring voltage down to a safe level , but since im currently running a LED rear tail it can not be run on AC So ill run a spare rectifyer/diode in series and that means I can run a 12v glob head light and a led tail all bright nice and steady..
Hopefully..