Hydraulic Pump Motor Control Options

[iaindunn]

Hi again. just thought I would include a pic of my control board amd circuit diagram. This has 3 speed controllers and the hydraulic pump switch on it. The pump switch is good to about 4 amps without heatsink but can go up to 12 amps with a heatsink.
The pump switch is the bottom PIC chip. Not sure if the diagram will be big enough as an attachment.

[rc_farmer]

Is the pump all you can run off this board?

[iaindunn]

No the board has 3 escs' on board as well, 1 for slew and 2 for track motors and a 5v supply .

[tfmacz]

Hi Iain
is is possible you could share the pic hex files for both the H-Bridge drive pics and the pump switch pic.

I can program pic's and a couple local guys would like to play with you design.

Thanks for sharing

Originally Posted by iaindunn

Hi again. just thought I would include a pic of my control board amd circuit diagram. This has 3 speed controllers and the hydraulic pump switch on it. The pump switch is good to about 4 amps without heatsink but can go up to 12 amps with a heatsink.
The pump switch is the bottom PIC chip. Not sure if the diagram will be big enough as an attachment.

[iaindunn]

Would you prefer the assembler as you then play around with it in mplab ?
I have posted the assembler for the pump switch above:
Below is the speed control based on microchips simple esc desigen but rewritten to give forward and reverse. The track motor controls are on one 12f675 and are simply forward and reverse for both run off toggle switches on my trasnmitter. I did do a 2 speed version but didn't gain much from it:

Any questions just ask.

Iain

[tfmacz]

I am looking to take some shortcuts to start with. So If you have the .hex binary files would save me some time initially. I use Eagle for pcb design and I make prototype pcb's on a small cnc mill built for the purpose.
I have your schematic diagram, could you post an image of the copper side of the pcb? It will save me some layout time.
I don't currently have mplab installed anywhere.

Looks like I will have to rebuild my development box.
Thanks for all your help.
Ted

Originally Posted by iaindunn

Would you prefer the assembler as you then play around with it in mplab ?
I have posted the assembler for the pump switch above:
Below is the speed control based on microchips simple esc desigen but rewritten to give forward and reverse. The track motor controls are on one 12f675 and are simply forward and reverse for both run off toggle switches on my trasnmitter. I did do a 2 speed version but didn't gain much from it:

Any questions just ask.

Iain

[fhhhstix]

Originally Posted by Espeefan

I would guess that like most things in life, there are always exceptions. Since the hydraulic pumps are coupled to the engine, it's not uncommon for the pump RPM to vary all the time too. Look at a wheel loader, for example. Lots of driving forward and backing up. In between, steering when the engine is winding down, or at idle, and lifting or dumping the bucket. Pump (oil flow) output varies quite a bit. Now something like a back-hoe or an excavator is a totally different story. Maybe even a skid-steer, but the demand for hydraulic flow on a machine that is constantly moving, and uses hydraulic motors for the drivetrain also, actually needs good flow, and maximium pump output. Then we also could consider the variable displacement hydraulic pumps, that put out more flow, when it is demanded, regardless of engine RPM.

So I would think on a small scale model there is no reason why the pump can't be throttled back to reduce heat, and increase battery life. Sounds like a win win situation to me. Heat is the worst enemy for a hydraulic system, next to oil contamination. Yes, you could put a heat exchanger on any hydraulic system, but on a scale model, it would be easier and cheaper to throttle back the pump, or shut it off completely.

Out in industry, where I work, we are starting to see some hydraulic pumps run with electric motors, and variable frequency motor drives, which throttle the motor and pump RPM back, when the flow is not needed. The worst is when an operator walks away from a machine and leaves it running. The oil is constantly going over the relief valve and the motor is drawing more power in doing so, while also heating up the oil for the next few hours. Yes, the heat exchangers cool the oil too, but it is still getting warmer then it normally would, if the machine is cycling.

Thanks for the explanation. Yes I did take offence!

I work for the CAT Rental Store and work on all kinds of hyd systems by a lot of different manufactures JLG, Broderson, LULL, Bell, Trail King, and the list goes on but hay my boss will be glad you explained to me how it works.

All I am saying is why over complicate some thing you can take care of with a cheap switch or cooler.

Originally Posted by egronvold

You can get a suitable ESC for $8 But you do need a radio with at least 2 free mixes.

$8 esc shipped from where and will last how long and who warranties it.

Travis

[Espeefan]

Originally Posted by fhhhstix

Thanks for the explanation. Yes I did take offence!

I work for the CAT Rental Store and work on all kinds of hyd systems by a lot of different manufactures JLG, Broderson, LULL, Bell, Trail King, and the list goes on but hay my boss will be glad you explained to me how it works.

Travis

Travis, I know you work for a Cat Rental Store. Relax. I'm not out to bust your chops. If that's what you think the purpose of my post was, I apologize. I was just making a point that pump speeds and outputs vary all the time, so why not do it with a model too. Given the choice, I'd throttle back the pump, AND have a heat exchanger, but if you only do one, I'd throttle back or turn off the pump altogether. Reduce the current draw, and save wear on the components. That's just my opinion. Everybody has one. You don't have to accept or like them, nor take offense to them. I'm just saying....

[egronvold]

Originally Posted by fhhhstix

$8 esc shipped from where and will last how long and who warranties it.

Sold at hobbyking; Turnigy 30A (not including shipping). It's quite small, which is good since space is often limited. I think a ESC is a good option in loaders and ATDs, but in an excavator you might as well go for an on/off switch.

My two main reasons for using ESC/ switch are not to have to listen to the awful sound of the hydpump when full flow is not necessary and to avoid unnecessary draw of current.

Many may think there's a delay in the hydraulic functions when using ESC/ switch, but there really is not. You can save a lot of AMPs just learning to operate machines with hydraulic steering by just driving "smart" --> less battery changes = more fun

It would also be cool to change the counterweight on the trackloader to a heatsink with a fan. That would be almost as "the real ting" I guess.

[fhhhstix]

Originally Posted by egronvold

It would also be cool to change the counterweight on the trackloader to a heatsink with a fan. That would be almost as "the real ting" I guess.

Izzy and I talked about it and it would be cool but I felt it was a bit unnecessary for a toy. Right now with my loader set up it will run for 45-60 min on a battery and that is fine with me. As for the esc yes it has a good purpose but I like to keep things simple and it also give newcomers a simpler way to do things till they get to know their equipment and radios.

Travis

[iaindunn]

Originally Posted by tfmacz

I am looking to take some shortcuts to start with. So If you have the .hex binary files would save me some time initially. I use Eagle for pcb design and I make prototype pcb's on a small cnc mill built for the purpose.
I have your schematic diagram, could you post an image of the copper side of the pcb? It will save me some layout time.
I don't currently have mplab installed anywhere.

Looks like I will have to rebuild my development box.
Thanks for all your help.
Ted

No worries Ted.I'll dig ou the hex files and my layout over the weekend and post here.

Iain

[iaindunn]

Originally Posted by iaindunn

No worries Ted.I'll dig ou the hex files and my layout over the weekend and post here.

Iain

Hi Ted could you pm me and I'll send over files. I use express pcb for layput and schematic and not sure how to post thos here.
I

[tfmacz]

Originally Posted by iaindunn

Hi Ted could you pm me and I'll send over files. I use express pcb for layput and schematic and not sure how to post thos here.
I

Hi Iain
I think you should be able to attach the files like any other file. Like when you attached the .txt files for the source listings.

I sent you my email address in a PM. The Express PCB files might be useful, My buddy has used that in the past.
Cheers..
Ted