@Bill: I assume downstream of the power source, such as between the power source and the throttle? I am assuming a standard fuse holder and fuse would work? I can look for a resettable breaker, as I imagine that would be more durable.
@Cliff: The benefit of a good Dad and getting married later than my peers!
Yes you could use a fuse and holder but if it blows you don’t want to be trying to remember where you put the spares, LOL
Well, if he is building a box to put this thing in, then he can build a small compartment in the box for spare fuses.
blade type fuse and holder, available at auto parts store, walmart, etc.
Greg Elmassian said:
blade type fuse and holder, available at auto parts store, walmart, etc.
Why a fuse over a resettable circuit breaker?
Probably for a faster blow.
Right, and also easy to change to different amperage… and inexpensive, easier to find on the island, and smaller…
By making it easy, if you experiment a bit and pick the lowest amperage fuse that does not blow in normal use, then if there is an issue, the fuse will most likely blow sooner and avoid damage to the loco.
I’m a witness to a 9 amp short in a system that only had a 10 amp breaker:
Gents,
Thanks for your input. I went to the hardware store today, and one of the employees happened to be an electrical engineering graduate student. Yay! With his help, I was able to source all supplies accept for the power supply right there. I prefer to deal with a local business, as this is a.) good for me as I learn something and save on shipping, b.) good for the local economy, and c.) facilitates exchanges when I invariably get the wrong thing.
Below please find the components, from left to right:
DPDT switch for direction control -> fan speed controller for speed control (I just liked the slide vs. the knob) -> fuse holder and 5 Amp fuse (all they had) -> Socket for power sources to track -> male connecter for wires leading to track. The lot cost me $65 for enough to make two controllers, which is about what it would’ve cost me online.
I have a bunch of wire left over from a ceiling fan I installed. I figured I didn’t have to show that! Beyond that, anything I should return / exchange / suck up and order on line?
I am still debating the laptop style power source vs. the “desk top” style power source. The former seems more rugged and has no exposed terminals; the latter would allow for one control box and minimize chords but leave the 110V wires nominally exposed. I can see what might be available locally, then go from there.
Again, I really appreciate the help and advice. This has saved me a bundle to date.
Have a great week!
Eric
OK, so:
return the fan controllers.
get the school this guy graduated from, call the dean of engineering and have him revoke that guy’s degree and have him change his major to fantasy football, or expel him.
be sure that anyone that works on anything electrical in your house has not attended this university.
You CANNOT use a triac/diac to vary the voltage to a switching power supply… absolutely insane…
Greg
To further explain, fan controllers normally only work on incandescent lamps, and certain kinds of motors.
Your power supply for your laptop that you are going to use most likely will work from 90 volts to 240 if it is modern. So right off the bat you can see it won’t work. But wait, it gets worse! The fan controller is not actually reducing voltage, but it is reducing average voltage because it is pulse width modulating the AC sine wave.
So, it should really make the power supply nuts, or overheat or both.
Now, these fan controllers are designed to work on 110v AC… so my assumption so far is he thinks you can vary the output voltage of a regulated power supply (no way) by varying the average input voltage… that is insane.
But maybe he thought you could put the fan controller on the DC output… also wrong, since these units normally depend on AC to run their circuits.
Greg
Greg,
I can’t thank you enough; it seemed a bit strange to have AC components on a DC circuit, but, as mentioned electrical engineering was my academic kryptonite. I am good enough to draw a diagram of what I wanted to do, though, so I am surprised he didn’t understand where I was going. I had held off ordering the power supply / supplies pending a parts review and a quick run to Target for suitable boxes, so no harm done to wallet, trains, or - most importantly - persons.
I’ll get the fan controllers returned and put the money to the proper controllers I saw available from the store recommended earlier in this post.
Again, my sincerest thanks for taking the time to review this!
Aloha,
Eric
No problem, I’m really surprised that this was a graduate student, but as being in the same place long ago, school gave me little practical knowledge, I learned a lot by doing.
The funny thing is that even as a person who only has an BSEE knows that circuits act very differently on AC vs. DC. How he assumed an AC controller would work on DC is troubling.
Now, from the “theoretical” perspective, I guess he thought there was just a transformer in your 24v power supply. The fan controller would have some effect on a plain transformer, but still heating would be a concern, since by using PWM, you are altering the frequency in a way, and transformers don’t usually like to have their resonant frequency changed!
Anyway, your original plan is sound, be sure to pick up that automotive blade fuse and holder.
dunno if you can find one with an LED, looks fun, but I posted this because the picture was larger
The funny thing is that even as a person who only has an BSEE knows that circuits act very differently on AC vs. DC. How he assumed an AC controller would work on DC is troubling.
I only have an Associates degree and even I know that.
Heck, I learned that to some degree when I was pre high school and playing with my trains. This is such a great hobby.
Eric Mueller said:
Gents,
Thanks for your input. I went to the hardware store today, and one of the employees happened to be an electrical engineering graduate student. Yay! With his help, I was able to source all supplies accept for the power supply right there. I prefer to deal with a local business, as this is a.) good for me as I learn something and save on shipping, b.) good for the local economy, and c.) facilitates exchanges when I invariably get the wrong thing.
Below please find the components, from left to right:
DPDT switch for direction control -> fan speed controller for speed control (I just liked the slide vs. the knob) -> fuse holder and 5 Amp fuse (all they had) -> Socket for power sources to track -> male connecter for wires leading to track. The lot cost me $65 for enough to make two controllers, which is about what it would’ve cost me online.
I have a bunch of wire left over from a ceiling fan I installed. I figured I didn’t have to show that! Beyond that, anything I should return / exchange / suck up and order on line?
I am still debating the laptop style power source vs. the “desk top” style power source. The former seems more rugged and has no exposed terminals; the latter would allow for one control box and minimize chords but leave the 110V wires nominally exposed. I can see what might be available locally, then go from there.
Again, I really appreciate the help and advice. This has saved me a bundle to date.
Have a great week!
Eric
Eric
I use these computer supplies, no exposed terminals fan cooled and mine has been running for over 6 years. I also live in a high humidity climate close to the coast and have not had 1 bit of trouble with them.
There are instructables on how to convert them to bench supplies which overcomes the load sense and fools it into thinking its connected to a computer. From memory its just adding a resistor across the 5V rail.
I use the 5V and 12V outputs with one 12V having an LM338K variable regulator on the output this give me a max of 11.3V which may not be enough voltage but enough current to run a loco.
This is the one Eric found,
considering the humidity and having kids, $15 for a completely enclosed 24v power supply with 5 amps is hard to beat.
Even though Eric is not racing trains, 12v is too low for most G scale locos…
I would put 2 in series to get 24 volts. In fact I did that with some old Lambda regulated supplies and they are still running fine.
I did check to make sure the output had no contact to neutral or ground on the input. Very important to do this when stacking supplies in series!!
check to make sure the output had no contact to neutral or ground on the input. Very important to do this when stacking supplies in series!!
Oh yes it is.
Gents,
Thanks again. I returned the fan controllers and used the money to get cheap tool boxes for the components. After much hemming and hawing, for this go around I am going to go with the 24V/5A “laptop style” power supplies to accommodate my lack of skills and lingering kid-vs-controller concerns. I’ll get the remaining parts flowing tonight or tomorrow.
The end result will be two self-contained throttles sealed with duct tape to keep out casual fingers with a socket for “power in” from the 24V/5A supply and a socket for “power out” to the rails. I am sticking with socket for “power out” as it should make it easier for the older kids to hook up and eliminate the ritual screw driver hunt when we shut down at night.
Thanks again for the patience and guidance. This project was way out of my comfort zone when Bill suggested I look into it. Saving $300-$400 and doing so safely is huge.
Have a great week!
Eric
OK,
Power supplies, power chords, the connector to take it from the power supply to the throttles, and voltage controller are on order. Naturally, I left off the voltage controllers, but hopefully my note and e-mail will get to them in time to save me the $8 shipping.
We have crossed the proverbial Rubicon…
Eric
Socket for power in and a socket for power out. Good idea, just be sure and use 2 different type sockets. I know, you will mark them, but if they can be plugged in wrong, they will be, by someone, despite being marked. I know from personal experience.