I have been thinking about the proper way of mounting such parts (fuse holders, jacks etc) on metal chassis.
Some of them have a D-shape axis, I think everyone has come across such parts. So, the best way of securing these from rotating is to cut a D-shape hole. Not an easy one or whatever.
I think that what I must do is use locking washers, the ones that have teeth for example. I suppose that this is a quick and cheap method of securing almost everything.
Does anyone have experience on the use of such washers? Do you think that it is sufficient?
Some of them have a D-shape axis, I think everyone has come across such parts. So, the best way of securing these from rotating is to cut a D-shape hole. Not an easy one or whatever.
I think that what I must do is use locking washers, the ones that have teeth for example. I suppose that this is a quick and cheap method of securing almost everything.
Does anyone have experience on the use of such washers? Do you think that it is sufficient?
Does anyone have experience on the use of such washers? Do you think that it is sufficient?
for speaker terminals it is not enough
one thing you really do not want is a speaker terminal moving when mounting a speaker wire
It is meant only for fuses and power jacks - where power jacks could be tiny XLR, DIN connector (most possible) or typical cheap 2.1 jacks for guitar pedals.
Many thanks for the answers!
spwalek: I did not figure out what you mean by "twisting on the holder"!
how about secure/safe fuse holders ?
could you be please be more specific/precise about what problem it is you need to solve
how about secure/safe fuse holders ?
could you be please be more specific/precise about what problem it is you need to solve
I am building a power supply to power up 11 effect pedals for guitar use. This will require that I have 12 secondary fuses at the rear of the box.
But I want these fuses to be easily replaced during a gig. So I planned to use regular panel mount fuseholders like this.
For the layout that I plan to use, check this thread, post 78.
So I just say that since regular fuse holders are D-shaped, I want to come up with an easy way to ensure that they don't rotate, other than drilling a D-shape hole.
EDIT: What is this secure holder you are talking about?
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one where you won't have to touch the fuse when in curcuit
could be the like the one you suggest yourself
I would suggest a fuse drawer ... since it has room for a spare fuse
but harder to make the square holes
and with that many you need ...
I know its good practice to use multiple regulated supply in those 'power bricks'
but do you really have fuse them all seperately
actually, with this low power, do you need to fuse more than incoming mains voltage
one where you won't have to touch the fuse when in curcuit
could be the like the one you suggest yourself
I would suggest a fuse drawer ... since it has room for a spare fuse
but harder to make the square holes
and with that many you need ...
I know its good practice to use multiple regulated supply in those 'power bricks'
but do you really have fuse them all seperately
actually, with this low power, do you need to fuse more than incoming mains voltage
You are quite right about the need to fuse everything - with one exception: the regulators have internal shutdown, so high that if so much current goes through, other componens could be at peril. Notably, the 2R2 5W smoothing resistors I plan to use would just be at their limits (around 5W dissipation at 1.5A) but the inductors I also plan to use for HF attenuation, 560uH at 0.4A DC, could be in danger.
That is what I suppose!
I would suggest 'ordinary' regs, and maybe cap multipliers
if done properly, thats all you need
make it reliable and don't take any chances with these tings
btw, each output should all have their own individual supply regs, so I'm not sure I understand your 'dissipation problem'
first smoothing at trafo does not need to be be regulated, but could just be ordinary bridge and caps, thats all
if done properly, thats all you need
make it reliable and don't take any chances with these tings
btw, each output should all have their own individual supply regs, so I'm not sure I understand your 'dissipation problem'
first smoothing at trafo does not need to be be regulated, but could just be ordinary bridge and caps, thats all
Well you need to read that thread to understand what I am talking about!
In short, 12 separatel secondaries, each one in the following style: bridge - RC filter - LC filter - regulator - load. Should 1.5A pass from each regulator (say its upper limit) and then cut by its internal circuitry, this 1.5A will pass through the RC + LC filtering stages that come before the regulator. And the resistor of the RC section is a 5W component, could possibly withstand so much current - the inductor is rated at 400mA only, though. The safe way of ensuring that no more than 500mA or so pass through these components, is to fuse the secondary (based on simulations or experimentation). All this could be regarded as pointless, but I think it makes sense: during a gig, I would not like to fry an inductor before understanding that something has gone wrong.
I think we are a bit off-topic.
EDIT: Higher current than what I need but less than the current the LM317 needs to "feel" to shut down is my concern. Still, higher current than what I need should insert additional voltage drop before the regulator, possibly threatening the 3V dropout required. I don't know what happens if the input of the regulator sags below its output - does it shut down? If so, we could say that the regulator's internal protection against short circuits is enough to protect the R-L components.
Still, what happens if, for instance, the second cap (of the LC section) breaks down? Then I assume that we would have a short circuit before the regulator - so it cannot help. If the resulting current is double the working current (assuming the capacitor had a small reactance at 100 Hz already, so the effect of it being short-circuited is not that devastating) the inductor could be at peril again.
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thats what I suggested... quit the RC LC resistor coil crap, and do it properly with regs and cap multiplier
that other stuff is for hifi
but if you only want to talk about fuses ... fine
Haha, of course and I don't want that! Off-topics are possibly your concern (as a moderator
), I like them! Well I have designed this on this RC LC easy way, I am sure your solution is excellent. I will see whether I can easily implement what you propose, thanks for the advice!
Off-topics are possibly your concern (as a moderator
mostly concerned about thread crapping
a tough indestructable 'cap multiplier' is very easy to build
place it right after your first bridge/cap smoothing
it will feed your regs 24/7
Well I know that, but I am a bit concerned about the additional voltage drop. I have designed eveything based on the RC-LC combination, worst case mains etc.
So I have ordered the transformer. The secondaries are 13.5V at 0.45A. So I am trying to find a capacitance multiplier that won't drop the input voltage to the regulator below 12-13V.
How about using a BC337-40 and a 1k-100u filter for the multiplier? Do you think it is a valid choice? Can the BC337 cope with 200mA rms easily, without the need for a fancy sink? Because if I am going to make my build bulkier, bigger and more expensive when using a multiplier, I think it is not worth it.
EDIT: I performed a simulation usind a BD135-16 plus a 100R-220uF filter, with 2200u reservoir, and the result seems very good! Do you think it's a good choice?
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Not the only way and not the safest.
What is the reasonable maximum current draw on each supply?
Insert a 3pin regulator CCS prior to the voltage regulator. Set the CCS to: maximum current draw * 120% + 10mA.
eg
200mA current draw.
120% is 240mA
add on 10mA for a total of 250mA for the CCS.
The 3pin regulator as a CCS outputs ~1.25Vdc across the limiting resistor. Use a 5r resistor. R = 1.25V / 0.25A
Use two 10r in parallel.
Dissipation in each resistor is 1.25V^2/10r = 156mW. Use >=400mW resistors.
You could use a 600mW 5r1 single resistor giving the CCS ~245mA.
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