Stuff you have made today

[nickk]

Some more restaurant steelwork back from the galvanisers.

 

[mtt.tr]

Pretty good day, first job was the landrover latches from the original series to antiburst what an improvement.

Then set the printer to print the rocokola stereo badges, not only do we have the princess (thread to come) we now have the wall speakers just needed the decals, found these on thingiverse result



Then a little bit of tin bashing, haven't been the workshop in far to long been to busy was nice






These are also jukebox parts

 

[Wedg1e]

If you made one more you could have quadraphonics

 

[mechman]

If it runs only at full speed that does mean the mosfet is blown, they usually fail shorted. In other devices where the current is not limited by a motor, they can make a very big bang.

Diode spec your looking for reverse voltage and recovery time.

Mosfet any 20A+ N type should do. If you are buying one of the switches for your drill, you could take the old mosfet from that.

Haven't a clue about electrickery ( and most other things) what does a diode exactly do?

 

[Kram]

Ta. Going to sound dense here but what makes the 6A8 / 10 potentially suitable?

Cheers

Ignore that, Im an idiot. For this, they are connected in reverse, so the reverse voltage rating is irrelevant, but no downside to the bigher rating.
Had a quick look, the ones I use for this are 1n5408's.

Haven't a clue about electrickery ( and most other things) what does a diode exactly do?

In this case its a one way valve, connected in reverse accross the motor. Spikes flow through the diode instead of damaging the mosfet and other bits.

 

[Onoff]

Ignore that, Im an idiot. For this, they are connected in reverse, so the reverse voltage rating is irrelevant, but no downside to the bigher rating.
Had a quick look, the ones I use for this are 1n5408's.

In this case its a one way valve, connected in reverse accross the motor. Spikes flow through the diode instead of damaging the mosfet and other bits.

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.

 

[RWD3M]

Today I replaced this [its twin brother was already dead, having been glued back together several times] useless, cracked safety shield for the grinder

View attachment 279036

with these - £10 + post for the pair ex eBay, less than I would have paid for 'genuine' ones. These are 'proper' guards

View attachment 279038

Have they got cheater lenses in them John?!

 

[Onoff]

View attachment 281134

Can I use that as my avatar please?

 

[Fraserb]

Can I use that as my avatar please?

I'll send you a better picture of it, that one was a photo of my screen

 

[mechman]

Ignore that, Im an idiot. For this, they are connected in reverse, so the reverse voltage rating is irrelevant, but no downside to the bigher rating.
Had a quick look, the ones I use for this are 1n5408's.

In this case its a one way valve, connected in reverse accross the motor. Spikes flow through the diode instead of damaging the mosfet and other bits.

It's school time, mosfet

 

[Fraserb]

Can I use that as my avatar please?

 

[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)