12V dc reversing speed controller

[MCKDAVID]

have to build up and machine back a worn out bearing sleeve off an idler wheel for a mini digger, so have been motivated to finally build the weld positioner I have been sourcing the bits for.

Was planning to use the parvalux motor and reduction gear box, but concluded that would be complicated for pulleys and physical size, so have settled on a 12V version, just using bits I have.... Have the angle gearbox, pulleys, belts, power supply and motor etc. Tried the motor off load, (think it's around 750 W) and it's pulling 35amps, which would probably double on load, so looking for a speed controller with a capacity of around 100A to give me a 30% safety margin.

needs to be reversing too. Had a scan on google and found this one, but don't have a lot of confidence in Wish. Looking for a "decent" one that'll last more than 5 minutes.. or a simpler solution for dc speed control?

any of you electrical / electronics gurus have any recommendations, thoughts .

 

[hotponyshoes]

The guts from a cordless drill might do the job but maybe not for that sort of amps.

I have used a few of those Chinese speed controllers and they don't seem to cope with anything like the amps they claim.

You are going to have to find some way of supplying it with 100a at 12v anyway so what about an adjustable lab type power supply?
You may have to remove the control pot and fit it to a pedal and fit a manual switch for direction control.

You may have more options (better quality) if you went to 24v. Personally I would be looking at a lower power motor at higher rpm and adjust the gearing to suit but I appreciate you may be using parts you already have

 

[MCKDAVID]

The guts from a cordless drill might do the job but maybe not for that sort of amps.

I have used a few of those Chinese speed controllers and they don't seem to cope with anything like the amps they claim. Exactly my thinking..... they seem to have small horses over there... hahahha

You are going to have to find some way of supplying it with 100a at 12v anyway so what about an adjustable lab type power supply?
You may have to remove the control pot and fit it to a pedal and fit a manual switch for direction control.

You may have more options (better quality) if you went to 24v. Personally I would be looking at a lower power motor at higher rpm and adjust the gearing to suit but I appreciate you may be using parts you already have

well that was my plan to try and use up existing bits, and ideally get it done asap, so I can knock teh job out.. I've looked at some positioners on the market, and you can get them for 250 euros, so probably more hassle than it's worth, but that's the bottom of the market and dopn't look up to much, so probably not much better that I could put together myself..

Aye tried with a battery drill, and it would cope I think, so might yet rethink the 12V motor idea, as it seems to run into a wall pretty quick, especially given the current. The battery drill isn't a bad shout, as it basically has all the bits already, multiple gears, variable speed and reversible..

off to rethink, bit early for a beer though.....

 

[hotponyshoes]

Just have a look at the specs/manuals for the drills first.
Some of them vary speed and torque so have very little torque at low rpms.
Others vary speed but keep constant torque and others keep the torque at all speed ranges.
You might also find the switch needs to be relocated to the pedal so you might want one that does not have the fwd/rev integrated into the switch

 

[gaz1]

 

[MCKDAVID]

aye thanks Gaz, saw those, good solutions...

been faffing about all morning, and have the solution, more or less, definitely going with a battery drill option. after thinking about it, it's not for production work, so battery power is fine, if I have to wait for batteries to charge up, I can live with that. also makes it more portable, so can store it out of the welding area when it's not needed...

now the complicated bit, making it simple... ahahhahah

 

[Johnnybravo]

Mine was built using a server psu. 12v. Speed control is a pwm 20A dc controller. Didn’t bother with reverse. It is easy though. I did it on my bead roller. Same set up but 24v had by daisy chaining two server power supplies together ( done properly, not the potentially lethal way on insulating one case and cutting the ac earth). Direction control and brake via two relays. Figured it was a better option than a reversible speed control, as direction can be changed but the speed is the same

 

[Johnnybravo]

Mine also has two gurt sprig loaded carbon blocks to get the earth to the chuck without it trying to go through the bushes or bearings. It was a production machine for welding up bogey wheels for a production line prior to remachining. Paid for itself rather quickly!

 

[rikrobson]

Are you sure you have the figures correct for the motor? 750W is an awful lot for 12V.

 

[MCKDAVID]

Are you sure you have the figures correct for the motor? 750W is an awful lot for 12V.

small engine starter motor, have a box of them. Small physical size, so thought it would be fine but apparently not.

 

[MCKDAVID]

Mine also has two gurt sprig loaded carbon blocks to get the earth to the chuck without it trying to go through the bushes or bearings. It was a production machine for welding up bogey wheels for a production line prior to remachining. Paid for itself rather quickly!

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looks good, this will be a lot simpler I hope...

aye for the welding return, I was planning on stripping back some heavy welding cable, crimps on the ends, one fixed, the other with a heavy spring to maintain contact with the tube below the chuck.

 

[Barking Mat]

That second video is @Robbie260 , if I remember correctly, here on the forum.

Nice build Robbie incidentally.

 

[Johnnybravo]

small engine starter motor, have a box of them. Small physical size, so thought it would be fine but apparently not.

You don’t need anything near that. Starter motors are intermittent use only. I used a window winder motor and a lot of gearing. Get it in the ballpark with gearing and fine tune with the speed control. The gearing gives more than enough torque

 

[MCKDAVID]

You don’t need anything near that. Starter motors are intermittent use only. I used a window winder motor and a lot of gearing. Get it in the ballpark with gearing and fine tune with the speed control. The gearing gives more than enough torque

aye, learning as I go here, just trying to use up the crap I've accumulated...

 

[Robbie260]

That second video is @Robbie260 , if I remember correctly, here on the forum.

Nice build Robbie incidentally.

Ummmmm thanks Matt I really appreciate the Kudos but since I have never put a video up on YouTube or any other social media yet I doubt it's me. For future reference this weirdo is me.

 

[Barking Mat]

Ummmmm thanks Matt I really appreciate the Kudos but since I have never put a video up on YouTube or any other social media yet I doubt it's me. For future reference this weirdo is me.

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Who am I thinking of then ?

 

[Barking Mat]

Ummmmm thanks Matt I really appreciate the Kudos but since I have never put a video up on YouTube or any other social media yet I doubt it's me. For future reference this weirdo is me.

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Love the Minion reservoirs...

 

[Robbie260]

Love the Minion reservoirs...

Yes they are awesome.