I'm interested in dissecting a broken diode cutout and was wondering if anyone had any that no longer work. I want to see what it needs to be rebuilt. Email me at firstname.lastname@example.org
Since the correct diode installed correctly is likely never to fail - you would be wise NOT to copy a broken one. Many home brew attempts at converting the mechanical cutout to a diode type have resulted in failure for 1 of 3 reasons.
The wrong device was chosen in the first place.
The device chosen was not installed with adequate attention paid to "heat sinking"
The generator charge rate was set way too high and this results not only in diode failure but also generator first and then often battery failure too since the battery can very easily be overcharged when using a cutout rather than a voltage regulator. When using a cutout - the charge rate is fixed and constant so for sure at some point the battery will begin to overcharge unless the drive in the T is very very short indeed.
Assuming your Model T charging circuit is in correct working order get yourself a FunProjects Voltage regulator and you will have a bullet-proof battery charging circuit.
The FP VR modulates the generator charging output to the battery based upon it's need for replenishment. Hence; The battery is not boiled by uncontrolled generator output and the long suffering Model T generator gets a rest.
Ron the Coilman
Hmmmm... Can you explain how the battery can become "overcharged" and fail? It is my impression that this cannot happen (even with the original style cutout) as long as the charge rate is not set too high and there is water over the plates in the battery.
In a perfect world you are absolutely correct, but the original Model T charging system was designed in 1920 and is imperfectly applied today. In today's world how many Model T's have you seen with the generator charging rate set too high and the water boiled out of the battery?
The original Model T charging circuit is of marginal design! The cutout operates and the battery gets charged regardless of (owners whims) the generator's output.
In today's Model T driving environment therein lies the beauty of the FP VR. Using the VR the Model T generator output is modulated to charge the battery only to the extent it requires replenishment and at a LOW rate of charge.
I understand very well how the Model T charging system works and am ready to debate the aspects of using a FP VR versus a original cutout in today's Model T driving environment with anyone.
In my opinion the FP VR is one of the best modifications you can make to a properly operating Model T.
Ron the Coilman
And, I might add, The FP VR looks exactly like a cutout. So if you are trying to build a show car you should not loose any points.
I installed one of John's voltage regulators on my '23 T a number of years ago and it has worked perfectly ever since. However, since installing this regulator the T uses more oil, and the oil leaks out faster. Also the tires have worn and the paint is not as nice as it was before. John has absolutely refused to do anything about This.
If I go back to the Ford cutout, will these problems correct themselves?
Based on info you have previously provided, I can only conclude and repeat what I have told you in the past - namely - that your car is NOT a Model T Ford. It likely is some sort of GM product. There is a book, now out of print, called "Model T The Car That Changed the World" that I would recommend you obtain and read carefully. It also has large pictures in it if you find the words in the book too difficult. That book will help you identify what vehicle you actually own and perhaps lead you to eventually resolve whatever difficulty you are having.
John: Changing the subject and then asking me to purchase an expensive, out-of-print book, is not the proper way to treat a non-paying customer! Not only that but I just dame in from the garage and one of the tires is flat! AND it is a Model T...my mother told me so!
I just hope the new folks here understand the three previous posts. (Grin)
I just wish someone would pay attention to what Chris originally asked. Didn't seem like it was an unreasonable request.
Hey Mike, where ya been? I haven't seen you post for a while.
I would guess that what Chris was looking for was a Fun Projects voltage regulator to dissect. I have a burnt out one here that a customer gave me a couple years ago. I took it apart out of curiosity and there are a couple simple components inside. The main component looks like it has had the numbers sanded off it (or maybe that component is custom produced with no numbers?). With that said, unless you were an electronics expert with the proper test equipment, there would be no way of identifying that component.
As I understand it, if you have a failed FP regulator and you have not opened it up, I think there is some kind of specially priced repair deal that they offer. I think this would be the best course in "repairing" one.
Well I am so glad that my dear friend Bruce McCalley is still alive & well & remains so CHEAP . In our initial meeting Bruce refused to give the waitress a tip!
Edward R. Levy
P.S. All weak humor aside no one is more responsible for promoting this hobby & keeping it going than Bruce !! (I hope you had a great XMAS BRUCE)
EDWARD R. LEVY (the only true liberal still alive)
I'm still around and kickin'. Haven't been very active since I sold my huckster and my tudor. I have a very nice, restored 24 chassis which I'm getting ready to use for a depot hack. Hope you're surviving the holidays and having a great time!! Hope to see you in 2010.
I think Chris was wanting one of the regular diode cutouts.
Since there is a printed wiring board with more than a couple parts on it along with 2 or 3 more larger parts not mounted to that Printed wiring board, I am wondering what you had - it doesn't sound like one of our VR's since you stated there were only a couple parts inside of the one you had. You are correct that we offer a flat $20 test/repair/return on any VR that we have ever made. If the VR tests good then you get it back for only the cost of the return shipping thus you get a refund along with the returned unit. If its broken then you get it back repaired but we keep the whole $20. Actually more than 75% of them returned are OK. The only caveat on that flat rate is that the unit must NOT have had the cover removed (broken welds). In that case we will still repair it but it is then time/material since those generally are broken and/or have more than one problem. Sometimes those are beyond repair or at least the repair cost would exceed the cost of a new one.
Charging rate and batteries.
My understanding is a Model T generator (without a regulator added) is close to a constant current device for a given rotational speed, and the output does not drop off significantly as the voltage increases. The idea is to set the generator so it's charging rate offset the power draw on the battery on average. If successful the battery will stay close to fully charged. If the charge rate is slightly high then the battery will occasionally overcharge a little and some water may be lost. But a routine part of car maintenance used to be checking the battery acid level and filling with distilled water when needed.
The charge rate needs to be adjusted depending on the season and type of driving. A car driven in the winter with the headlights on most of the time will need a higher charge rate than when driven during the longer days of summer. And shorter distances with more frequent use of the starter motor and lower speeds generally require a higher charge rate.
So a car with a "properly" set charge rate can have an overcharged battery if driven on longer trips at higher speeds with less use of the headlamps.
Or the issue becomes moot if a voltage regulator is installed.
You have it correct on all scores. To elaborate a bit - there are 2 types of charging methods commonly used for batteries - constant voltage or constant current. Constant current assumes that the state of charge of the battery is known and the battery is then charged at a constant current to put back only the charge that the battery needs and then hopefully the charge is turned off. With constant voltage there is no need for a shut off nor to know the state of charge because the battery itself will regulate its own charge state IF a constant and correct voltage is applied to it. For typical lead acid 6V battery, that voltage is 7.05V and if that voltage is applied to a battery then the battery will draw current (up to ALL that is available) from that constant voltage source until the battery is fully and completely charged and then it will cease to draw current and just sit there in equilibrium at the 7.05 "float voltage". Think of a bucket that gets its water from a source that is exactly as tall as the bucket. Once the bucket is full it will not draw any more water from a source that is at the same level. Actually the cutout based system is worse today than during the T era because in the T era the T was rarely driven at high RPM constant speed for any length of time or distance. Thus a 1 hour ride in a T in the T era would result in less than 10 minutes being spent at speeds above 20 MPH most likely so a typical trip resulted in lots of low speed driving and even when the 3rd brush was set to say 10 amps (Ford's original recommended setting), the average charge rate would be less than 4 for the entire trip. A 1 hour ride in a T today would result in less than 10 minutes being spent at speeds below 25 MPH so a 10 amp setting of the 3rd brush would result in an average charge rate of near 10 amps for the trip. The cutout based system can really cook a battery because of the long sustained high RPM driving that we typically do now. Turning on the lights will lower the charge rate to the battery but not lower the work load on the generator - but - the problem is knowing exactly when to turn on the lights and when to turn them off since there is no real measure of the present battery charge level to go by. Before 1939 when Fords and most other cars started to get voltage regulators, battery shops were on every corner. They were as common as tire stores and batteries simply didn't last very long. After the VR was put on cars, the battery life lengthened and as the VR's got better the battery life got even longer. For daytime driving with a cutout, I recommend that the generator not be set any higher than 4 amps measured with an accurate ammeter. Your mileage could vary.