So connection for diode, not sure how to connect... if the case is live where do I take the connections too... Diode is top right with Yellow and Blue wiring attached...



Any chance someone could chuck up a quick hand sketch before I damage all the components again as it's starting to get expensive...

Think I really dropped one on the first attempt looking at it again today not sure if I inadvertently wired them in series...



Hence the reason only one component is blown...

 

Not sure what I'm seeing. I thought your diode was up on top of the 1st drawing, but here is the hook up.

 

Diode is on the top of the image, it's the one with the Yellow and Blue wiring attached... the second image is the original circuit...

I am using 6 fets as can be seen one dual diode...

Now I am confused...

So the positive from the battery goes directly to the frame?

The motor then flows through to the source pin and then out via the drain, is this correct so far?

Therefore the cathode is connected how?

Or are we back to how I was originally doing it and the case is ground and the supply flows through the source to the drain to the motor... in which case I can connect the diode to the drain and to ground...

 

You have to get around this idea of using the Chassis/frame connected to the +ve of the supply, draw it out as you normally would but make sure the -ve terminal is referenced to when taking measurements and viewing the circuit rather than the frame, and try and ignore the fact that the frame is positive.
Take virtually any circuit and it is purely arbitrary which terminal you make as 'Common'.
Max.

 

Are you using IRF4905 P ch FETs in a high side drive? Then I think that the motor frame in ground ?

 

The sources of the 4905's go to +12, the drain to the motor and the cathode of the diodes. The frame of the motor and the anodes of the diodes are ground.

 

So which is the better way, frame positive or source positive?

Only I am getting confused on this little bit of detail...

There has been some discussion on this, so which method are we going for?

 

Sinse you have 6 paralled P Ch FETs ready to go, I would go with post # 146 -- it is up to you for final decesion.
I think that multiple driveds might be in ord0er-- open for suggestions. For me, would use 6 555's as a driver for each FET.

 

My choice would be to use N Ch Mosfets and wire it up the conventional way the fact that the motor frame is at the +ve potential has no bearing on the circuit whatsoever.
A circuit board or component layout can still have a -ve oriented common. It is easy once the "positive frame" thoughts are completely ignored and the circuit treated like any otherwise convectional layout.
Also mounting Semi's to a heat sink that may be connected to +ve rather than -ve is no different and the same precautions have to be taken.
Max.

 

It really doesn't matter much. High power NFETs are easier to make so it wouldn't take as many. But either is ok. Your weak spot now is the diode. It may or may not be ok. We can't tell for sure because we don't know the start up current of the motor.
Before you fire it up, why don't you post a schematic so we can have a last check.

 

Hey, it has been more than a day in my part of the world. Still no schematic from Icarus. Have his wings been melted by the heat from the mosfets/diodes?

John

 

Hey, it has been more than a day in my part of the world. Still no schematic from Icarus. Have his wings been melted by the heat from the mosfets/diodes?
John

...or taken by a very big hawk!
Max.

 

Hawk? I have Bald Eagles at my farm, no kidding. I saw the first one last June about 1 mile away. One of my greatest pleasures of living in rural America is trying to identify the variety of fowl that are making a resurgence. I have a pond, and have seen a tern, crane, and stork this past Summer. The other birds really don't like the crane.

I have a flock of wild turkeys (>12) that walks across my front yard every morning and evening. Turkey season opens October 14th. I have never had a wild turkey. They look just like the Pilgrim pictures. Can't wait, but I suspect I will be disappointed in the taste. As for the OP, I have also spotted a falcon on the property. They are quite clever.

John

 

Speak of the devil...

Here they are just minutes ago.



John

 

The province I live in has one of the largest migration corridors for Raptors, eagles and hawks, a peak recorded in February and April of 2010, an estimated 11,000 raptors of 15 different species were seen travelling through the corridor, including Bald Eagles, Golden Eagles and Red-tailed Hawks.
Max.

 

sorry folks went on my Honeymoon, had no phone signal where I was located so unable to check in and post updates...

As previously stated I have no schematic software so will have to attempt a hand drawn schematic, not done one since college in 1996...

 

It really doesn't matter much. High power NFETs are easier to make so it wouldn't take as many. But either is ok. Your weak spot now is the diode. It may or may not be ok. We can't tell for sure because we don't know the start up current of the motor.
Before you fire it up, why don't you post a schematic so we can have a last check.

Just so that I am 100% sure what are you actually asking for the entire schematic as the timing circuit is attached...

All that I am planning on doing is using either output 12 or 13 to trigger the new circuit...

There is a 47 ohm resistor connected to the gate of each IRF 4905, so should be triggered from a single point on the gate...

 

What motor drive schematic are you using?
Belated congratulations on your wedding.

 

What motor drive schematic are you using?
Belated congratulations on your wedding.

Thank you Bernard, to be honest I don't have one...

 

Holy poop Batman, it works... YIPPEE

She is only running at half speed, but I can at least vary the speed... I am curious if I can alter the speed slightly to give me a wider speed range?

Using the shut down option I can immediately stop the unit in case of emergency... which is great news...

Nothing was getting too hot, slightly warm to the touch but nothing like last time...

Diode seems to be doing a grand job...

But she soon flattened the battery, I'm using a CT14B-4 which is a 12v 12AH battery

So I am thinking I may need a much bigger capacity battery to give me a few decent runs with the lure...

But thank you everyone for getting us to this stage...