DC motor_N-channel MOSFET's_H-bridge

[vicpopo]

Hi Speedy,
That is my day point from the h-bridge.
As I said I reworked 4 screws through hole to deep its heads into the copper disk.
Problem solved
I removed the insulate kit (brown sheet) and I fixed one more time the 8 mofsets ready to solder.I have to adjust each mofset angular position before screwing them firmly.I printed the a picture , I will make the adjustement with it.
The opposite board side is ready for soldering the 8 mofsets.
Pictures describing what I explained above.

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Copper disk reworked

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Mofset

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Mofsets fixed

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Cpu fan up view

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Cpu fan side view

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Top view board

That's all folk's for tonight.See you guys tomorow , have a good night for the paris ,londres , madrid gmt hours Xsimer.
Best regards

[speedy]

Good morning vicpopo :
I wish you slept well ... Great job my friend, Sorry ... I didn't realize before that it could be so hard for you.
Don't rush ...!! there is no one coming to finish line after you ...

Some bad news, You're going to rework that ... ... But for 1 minute rework it's good news ...

In the side view image of the Fan [Yes, a good photo from you it is seated good ] you can see the nuts are higher than the level of the MOSFET's which will face the board top layer directly then they will short touching it when been mounted ...

What to do ? ... Simply reverse the bolts heads ... right on top of the black isolators without washers and use the hexagonal shape of the nuts to give you the 1mm spacing required before to the Fan and small washers to fill the 4 holes leveled for a good tight bind ... ... I'm sorry ... Why didn't I said so first ?...!!! ...

Pls. do another MM [multimeter] test for MOSFET's isolation from copper disk and a microscopic visual inspection with the top side not touching bolts ... If Ok ... give us the result photo pls.

-Top side doesn't need to be tinned unless with some soldering for thin MOSFET's pads until it comes to a wider aria of copper Remember good ... another 1 minute rework ... The Side illumination of the last photo makes solder looks like Mountains ...

So try to enhance the solder layer evenly more [ Pleeease use a soldering grease ] sucking or moving the excess solder to the missed spots of motor mounting screws, power connections, and MOSFET's pads ... watch out for tracks touching together and do another visual inspection for MOSFET's CD bolts for a 1mm solid clearance in between ... give us a photo.

-Pls. Give me a start idea ,How you are going to mount the fan firmly solid to the board ...? What is your fan's dimensions ? Do they have additional brackets from the board down side ? I guess the Fan holes are not the same as the board outer 7x7cm holes ...!!!

- Prepare the bottom side with the missing parts if any ... remove IC's if installed and check with MM each IC base for short circuits between side by side legs ... replace back IC's and confirm every part in correct place and orientation and soldered good ... clean it and give us on top and 4 angles closeup photos.

With great power comes great responsibilities ...and you have the power ... just not ON yet .
thanks for your patience ...


regards
speedy

[vicpopo]

Hi Speedy ,
I don't yet finished to read your post because I was a step forward.
I bend the mofset legs and I will solder the mofset like the picture attached.
For the cpu fan I show you a little drawing I yet made.
Question 1 : if one mofset gnd is grounded to the copper disk what happens?
For cpu fan mounting like I want to do , I forecast to glue a piece of plastic in the center or the top board .With screwing the cpu fan firmly I don't have the risk to damage the mofset solders.If it's not clear I make a little drawing.
I confirm to you that the fan mounting positions are bigger than the 7x7 cm , It's the reason why I thought about the mounting as shown.
Best Regards

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Edit:I just finished to read your last post.Is it necessary to fix the mofsets so close to the board? I don't need to win a few mm , I just want that it works!!
One more thing why I bended the legs as shown it's because I have to adjust the 24 legs to the pads.Believe me my friends that will be a big deal doing this 24 solders.If the legs are to short it will be more difficult to adjust them.

[vicpopo]

Hi Speedy,
Better than a drawing.The real mounting!
Best Regards

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[speedy]

Yes My friend closer is way better and that is not a tight strong bond between copper disk and Fan base ...
Don't expect me to override that point pls.

if the MOSFET's legs is little off bent . there will be air gap under the fan's base thus no heat transfer between them .

And I just don't want any future accident [handling or future cleaning to the fan with a brush ]that could bend these long legs down cracking the solder and bolts will touch the top layer and getting tracks OFF the board ...

1- placing MOSFET's just on top of the board is perfect [ the board will support the MOSFET's and copper disk regarding isolation ]...
2- placing MOSFET's a little bit higher 1-2mm wont hurt [ the short and thick legs hardly can bend ]...

But this is so far away ... plus you are missing the benefits using the thick section of the MOSFET legs for 75Amps -TO-220 package limits ..!! choose #1 pls.

Answer 1:the MOSFET back mount is the Drain center leg that is the motor M1 & M2 terminals in one side [4 MOSFET's - Half of the bridge ] and they are the Positive power in the other side [4 MOSFET's - the second Half ] ... You need full isolation between these back sides specially under strong heat generated from each one of them ... you don't want these parts ever ever meet or touch the copper disk .

you asked me to make it work ... so listen to me pls. ...
best regards
speedy

[vicpopo]

Hi Speedy ,
Pls give me some informations before....
I'm a little furious because I broken mofsets legs ( 2 mofsets KO) trying to bend them shortly.
Adjusting the 8 mofsets so the 24 legs in both directions ( in the high and angular position ) is a nightmare my friend!!

I have to keep cool ... One step,forward 3 steps backward!!
Best Regards

[vicpopo]

Hi Speedy ,
I rework the as requested and I hope that it will works because if something would be wrong that will be difficult removing all mofset.
That's a point to discuss because if one mofset is KO you must remove all mofsets.
Pictures from the finished job! Hope will be suitable for you
Pictures:

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1

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2

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3

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4

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Side

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Front view

About the last picture for the trough hole n°1 I must via a screw connect the top board for the polarity gnd (-).The other trough hole n°2 is not necessary because the are 2 jumpers which connect the 2 boards faces (polarity +)
Best regards

[speedy]

Hi vicpopo :

Impressive improvements ... I guess you found a good chance to finish all this ... well done .
And easy my friend ... Don't be confused ... trust me you're doing very good . really .
you have a good sense and skills ... and the controller is easy to do with good results ...

Please Note: 1st & 2nd through hole connector are to supply high Amps. needed for the motors M1 & M2 connectors with the control of the MOSFET's ... Pleas use them and add solder to them to fasten the screws of the terminals ... plus they looks like they are not connected top and bottom layer on each hole from the beginning ...

Of course you know that these [ + , - , M1 , M2 ] are wired with strong 1mm lines cables from the battery and to motor regarding the polarity for the battery ... the other jumps on the board are to feed the control circuit down with it's needed pulses, grounding, gates protection, etc.
So, Pls. add solder to the mounting holes top layer ...


One step before power up ... confirm with Multimeter that copper disk is NOT IN CONTACT WITH ANY of the 24 MOSFET legs ...The fan base is firmly connected to the copper disk ...
IF All Multimeter testing are OK ..... Congratulations ... GO connect the AMC and motor, don't forget to give us the video of you motor running ...
woooof ... that's really a long thread ...

regards
speedy

[vicpopo]

Hi Speedy ,
Some pictures form the monster h-bridge!!
Whaou!! That is a h-bridge my friend , I love its look !! I really hope that it will works and that I didn't make any mistake
I checked the 24 legs and that is OK.

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4

Best Regards

[speedy]

Hi Speedy ,
Some pictures form the monster h-bridge!!
Whaou!! That is a h-bridge my friend , I love its look !! I really hope that it will works and that I didn't make any mistake
I checked the 24 legs and that is OK.
Best Regards

Prepare your camera first ... recording second by second ... and POWER ON ... what ever happens it should be recorded ...

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Pls. God ... some good news ... for this little poor man ... pleas, pleas ,pleas, pleas, pleas ,pleas, pleas, pleas ,pleas,



speedy