A simple and cheap current limiter for unipolar motors

[666]

Hi all... After posting my 3 axis pic design i promised to post the design of the current limiting circuit.

So here it is...

Hope someone can make use of it. I use it myself and it does the job...

Regards from Denmark!!!

666

[rippersoft]

Very cool! I was hoping that you would finish this and post. I have been looking for a simple way to use larger motors.

RipperSoftware

[666]

Erh... Finish it? What´s missing???

The pinouts are easy:

1. VCC
2. Motor1 common
3. Motor2 common
4. Motor 3 common

Calculate the resistor value, assemble the board, and connect the wires.

If you have any questions i´ll gladly help you.

Regards...

[666]

What size motors do you use???

I use these... The 342´s...

http://www.jvl.dk/files/pdf/ld042gb.pdf

666

[picbits]

Good work

I'll be using a PWM chopper drive on mine but might just whack one of these in at a slightly (+25%) higher current limit to act as a failsafe in case one of my PWM locks or tries to overdrive the motor.

[666]

A PWM is the preferred choice, but sometimes simplicity beats technology...

[picbits]

Simplicity quite often rules lmao.

I will be combining simplicity for the emergency protection side of things with complexity for the showing off side of things. All it takes is a processor crash with the PWM outputs locked on and you could rapidly burn out an expensive stepper.

[666]

Upload some pic´s of your device when it´s finished... Allways exiting to watch other peobles creations...

Goddspeed and regards from Denmark...

[picbits]

Will do - I've got to sort the machine out first - will not be concentrating on the electronics until the mechanicals are done. If my 26mm forstner bit ever turns up from Ebay (its been almost a week now) I'll be able to get on with my bearing mounts

I visited Copenhagen on company business a few years ago - drank far too much (very expensive) beer but it was a nice place to visit

[666]

I´m working on a cast alu design... At present time i need a small gantry mill. Will come up in another tread... For now i use my 2.1 ton Stanko Mill with MT#5 spindle... Heavy metal... And quite awkward to do PCB´s on!!! ROFL And danish beer rules! Good luck with your design. Looking forward to see your gallery when finished...

[rippersoft]

Originally Posted by 666 Erh... Finish it? What´s missing??? The pinouts are easy: 1. VCC 2. Motor1 common 3. Motor2 common 4. Motor 3 common Calculate the resistor value, assemble the board, and connect the wires. If you have any questions i´ll gladly help you. Regards...

Sorry, didn't mean to offend you. I confused your thread with DaRy who posted about a similar circuit using LM317.

Simple unipolar driver with current limiter

[666]

HEHE... No problem... Sometimes i forget that i made a board myself, and afterwards assume that everyone knows my projects as well as i do...
Just glad to help if anything should come up...

666