- Thread starter God mode restorations
- Start date
Thats better, Thanks.Best description (or comparison) of a diode is to think of it like a funnel: the water (or electrical current) is happy to flow through it one way but can't do so the other. Even the electrical symbol for a diode looks like a coffee filter holder
henry Kadzielski
Member
- Messages
- 1,208
- Location
- Australia Wollongong
The bottom machine, I have her twin sister, she is very happy here at my place
Woody.v8
Blue gluer
- Messages
- 4,154
- Location
- staffs
What's the dice?
Very nice my friend.
Fraserb
Member
- Messages
- 1,562
- Location
- Scottish Borders
There's been a bigger delay, had a rush job to finish.
Kram
Member
- Messages
- 6,855
- Location
- Sussex
If the battery polarity was wrong, that would have instantly exploded the diode, but Id expect it to take some time for the mosfet to fatigue from spikes.
Onoff
In the land of the unfinished project I am King!
- Messages
- 11,618
- Location
- Sevenoaks, UK
Right...I don't mind admitting my mistakes...
My finger is on the positive of the battery....spot the mistake?
Htf did I manage that? By getting the polarity marks the wrong way round on the 3D print!
Just the diode died d'you reckon?
Barking Mat
Cuddler of hedgehogs.
- Messages
- 12,917
- Location
- France, Brittany.
D'oh..
Kram
Member
- Messages
- 6,855
- Location
- Sussex
Ive done the same and worse!
Have you tried it correct polarity since? If the speed control still works, then just replace the diode
Onoff
In the land of the unfinished project I am King!
- Messages
- 11,618
- Location
- Sevenoaks, UK
Ive done the same and worse!
Have you tried it correct polarity since? If the speed control still works, then just replace the diode
I'll give it a go tomorrow. Cheers.
Material?
Dr.Al
Forum Supporter
- Messages
- 2,215
- Location
- Gloucestershire, UK
If it's a simple DC motor speed controller, it probably has a circuit that looks a bit like this (the coil is the motor - image stolen from google image search as I was too lazy to draw it):
The MOSFET has what's known as an "intrinsic body diode", so should look more like this:
As a result of that, you have two diodes in series, both pointing "upwards" (from negative to positive). If you connect the power supply the wrong way round, you effectively short circuit the power supply through those two diodes and one or both devices will go pop (probably at that current an internal bond wire will break and it will have an unconnected pin).
If you're lucky, one or other will have broken and the break will have protected the other one (but it's pot luck which one will go first). If you're unlucky both will have broken. If you're really unlucky, other devices on the board will have gone as well (lots of ICs have parasitic or protection diodes that point "upwards").
slim_boy_fat
Forum Supporter
- Messages
- 29,540
- Location
- Scottish Highlands
Today I made [well nearly finished] a pair of machine vice 'hold-downs for the pillar drill table [a big thanks to Mike @Wallace ] for the alloy blocks. 
Thanks to the Member on here who suggested the pattern, sorry but I've forgotten who it was
. They still need a tiny bit of fettling but I've proved they'll do the job - just have to get/make M10 bolts. Don't you hate it when a drill bit grabs and nearly breaks your wrist....
.
I want to radius the edges as they're sharp but don't have a suitably profiled milling cutter. I'm thinking I might carefully & gently try a router bit in the mill, but I'm not sure if they'll do alloy.....
. Answers & the address of a good A & E, please. 
Thanks to the Member on here who suggested the pattern, sorry but I've forgotten who it was
. They still need a tiny bit of fettling but I've proved they'll do the job - just have to get/make M10 bolts. Don't you hate it when a drill bit grabs and nearly breaks your wrist.....I want to radius the edges as they're sharp but don't have a suitably profiled milling cutter. I'm thinking I might carefully & gently try a router bit in the mill, but I'm not sure if they'll do alloy.....
. Answers & the address of a good A & E, please.
Last edited:
Hood
I am obsessed.
- Messages
- 17,308
- Location
- Carnoustie, Scotland
Handrail hinges fitted today, will let someone else do the polishing
and pic of the aft section hinged open and in the keeper.
The two cap screws below at either side of the stanchion are adjusters to get the rails sitting level when shut, they will be replaced by grub screws but had forgotten to take them so just shoved capscrews in to check all was well.
and pic of the aft section hinged open and in the keeper.
The two cap screws below at either side of the stanchion are adjusters to get the rails sitting level when shut, they will be replaced by grub screws but had forgotten to take them so just shoved capscrews in to check all was well.
zx9
Forum Supporter
- Messages
- 5,170
- Location
- South East London
Router bits will probably 'do' aluminium for a while, lubricate with WD40 and don't complain that they no longer cut wood nicely afterwards.
zx9
Forum Supporter
- Messages
- 5,170
- Location
- South East London
Rather him than me, I can trash end mills quick enough.
northwest
Searching for the Holy Grail.........
- Messages
- 5,757
- Location
- Manchester UK
Needed to make a couple of stools for the range as they have destroyed every type of bar stool we have had, some of em could break a cannon ball! Anyhow these are fast and dirty, fit where they touch tripod style stools. So while I was at it, going like a lunatic I decided to make a stand for my little folder. Naturally I should have thought it through a bit more but you only get to know this towards the end
Chopped a few bits up:
Mostly 30mm 3mm wall box but 40mm for the stand:
They came out well, made three stools:
Naturally, back at base I realised the error, cant get bolts through:
Ahhhh.... But I have a tig welder and some stainless bushes in 10mm:
Powder coat tomorrow.
Chopped a few bits up:
Mostly 30mm 3mm wall box but 40mm for the stand:
They came out well, made three stools:
Naturally, back at base I realised the error, cant get bolts through:
Ahhhh.... But I have a tig welder and some stainless bushes in 10mm:
Powder coat tomorrow.
