Stuff you have made today

[Kram]

So my "spike" took out both diode and MOSFET? Is there a chance the MOSFET is still OK?

I'm going to chuck another fiver at it.

If the speed control is gone, thats the mosfet shorted out. one of these should do,
www.ebay.co.uk/itm/2SK4075B-Trans-K4075B-MOSFET-N-CH-40V-50A-3-Pin-TO-252-x2pcs/291888928748

 

[Dr.Al]

It's school time, mosfet

A MOSFET is a type of transistor (Metal-Oxide Semiconductor Field Effect Transistor in case you're really interested). As such it's a switch that can be controlled by other parts of the circuit. FETs (as opposed to Bipolar Junction Transistors) are voltage controlled: stick an appropriate voltage on the gate and the "switch" between the other two terminals closes.

To drive a motor, you typically flick the switch several thousand times a second which makes a square wave and by varying the on time versus the off time, you get an average voltage that does what you want.

Motors are inductive & if you unplug something inductive with current flowing through it, you get a massive spike of voltage which can damage things. The diodes in the circuit provide a path for the current when the "switch" is opened & stop things from getting sparky & letting the magic smoke out of the FETs.

 

[slim_boy_fat]

Have they got cheater lenses in them John?!

Nah, the ones in the 'dead' shields were useless, but I do need cheap reading glasses for some jobs in the cave. Old age cometh not alone.....

 

[Onoff]

If the speed control is gone, thats the mosfet shorted out. one of these should do,
www.ebay.co.uk/itm/2SK4075B-Trans-K4075B-MOSFET-N-CH-40V-50A-3-Pin-TO-252-x2pcs/291888928748

Ordered! Cheers.

 

[Tangledfeet]

First thing this morning completed welding up this shelf that hangs off the side of the welding table. Goodness knows how much tungsten electrode I got through with dipping and regrinding, and in retrospect didn't clean the metal sufficiently - but it's the most AC TIG I've ever done!

 

[Blue Chips]

First thing this morning completed welding up this shelf that hangs off the side of the welding table. Goodness knows how much tungsten electrode I got through with dipping and regrinding, and in retrospect didn't clean the metal sufficiently - but it's the most AC TIG I've ever done!

Very convenient! Nice welding bench, too! You may have already thought of this, but you might want to rig some sort of cover plate (possibly an extension of the bench top?) over the welder to protect it from sparks/slag/grinder dust, etc. Clever use of the offset box-end wrench as a torch holder.

 

[mtt.tr]

It's school time, mosfet

Type of transistor metal oxide semiconductor field effect transistor, one of their big benefits though their are a number is it has a high gate impedance

 

[Farside]

Very Day of the Jackal.

 

[Hood]

Very Day of the Jackal.

Maybe Day of the Cheetah (catamaran)

 

[Tangledfeet]

Very convenient! Nice welding bench, too! You may have already thought of this, but you might want to rig some sort of cover plate (possibly an extension of the bench top?) over the welder to protect it from sparks/slag/grinder dust, etc.

@Blue Chips Thanks! Yes, I'm pleased with the bench (I did a review of it) and finally getting round to making some hold down clamps for the 28mm holes; the vast majority of clamps in the UK/Europe are 16mm.

I never do any grinding, flux-core MIG or stick welding inside the workshop; there's a large overhang just outside the door where I can do all that!

 

[Blue Chips]

@Blue Chips Thanks! Yes, I'm pleased with the bench (I did a review of it) and finally getting round to making some hold down clamps for the 28mm holes; the vast majority of clamps in the UK/Europe are 16mm.
I never do any grinding, flux-core MIG or stick welding inside the workshop; there's a large overhang just outside the door where I can do all that!

Good review of the bench! 28mm here in the US is quite common for larger industrial benches, while the smaller benches are often set up for 16mm/5/8" tooling., with exceptions for both. I see that you're already set up for making adapters with your lathe. As to grinding and other messy activities, it's nice that you have a sheltered outdoor area to do most of that in. I try to do most of the messy stuff like grinding outdoors when weather permits. I find that I often end up doing some grinding on something I've already jigged up on the welding table, since I sometimes forget to chamfer an edge, or there's the occasional messed-up weld that needs some attention, so I sometimes grind it in place rather than re-jig everything. For smaller messy jobs, I have a built-in steel-topped bench with a fairly powerful exhaust fan in the wall right next to it, which extracts a good deal of the dust from grinding, as well as most welding fumes.

 

[Cheesie]

Was asked to do the hoovering done this instead

 

[Fraserb]

Quicker than buying a set of shelf brackets.

 

[MattF]

You do know you have a tractor obsession?

 

[Fraserb]

You do know you have a tractor obsession?

These are for my 5 year old tractor daft small person, the rest are what ever anyone wants to pay for.

 

[Agroshield]

Quicker than buying a set of shelf brackets.

If you did them as tab and slot, would it be possible to make the welds invisible in normal operation?

 

[mechman]

Type of transistor metal oxide semiconductor field effect transistor, one of their big benefits though their are a number is it has a high gate impedance

Noooo I admit defeat, think I could learn Klingon faster.

 

[Brad93]

If you did them as tab and slot, would it be possible to make the welds invisible in normal operation?

Tab and slot on plasma is hit and miss

 

[Fraserb]

If you did them as tab and slot, would it be possible to make the welds invisible in normal operation?

Yeah could do right enough, I may have a second set to show in the near future

 

[brewdexta]

I finished off the wiring to the downlighter above the new beer engine I fitted yesterday, added a beer menu on the cellar/brewery door, fixed the PC next to the cinema screen, upgraded the software on the pellet boiler, took the dog for a good walk over the moors, now about to settle down and have a beer in the cinema and watch a good movie.

Cheers
Andy