How to run this stepper motor without toasting any chips?

[Triode]

I got some bipolar stepper motors from a surplus store and I'm getting ready to build a circuit to drive them, but since I have little experience with driving larger motors with electronics I want to make sure I properly protect the system. I'm using a pic18F4550 which is connected to my computer through USB, and I don't want to burn up either of them.

The motors are marked 2.4v 1.8A, 1.8 degrees per step.
STP-57D309-02 (haven't been able to find this or a part of it on google)
There are four wires Orange, Yellow, Brown, Red
The motor itself is a 2" cube.

I'm thinking of driving each motor with a L298n. The data sheet for a L298 says it can handle up to 46v, 4A and 25w, so technically it should be able to drive these steppers, it does seem kind of small for motors this size though.

Also, obviously I'm not powering these with USB power, so I'm going to have to feed the driver chips from a second stronger power supply. Where should I put protection diodes? I'm thinking from ground into each motor wire and from each to positive, like most stepper circuits, but will I need them anywhere else? And what spec of diodes should I use?

 

[OlPhart]

All major manufacturers have app notes on using their products successfully. Since they designed the product, nobody offers better advice.

Unipolar step motors are prone to fewer problems than bipole. It's why H-bridge chips are popular. I recommend starting with unipolar until you understand MOSFETs, drivers and their protection. Season to taste... <<<)))

 

[Triode]

Ok, well I've made circuits drive both several times, just not large ones. Since there are more experienced people than me here I thought it would be worthwhile to pick up any tips they might have about making the circuit more reliable. I certainly know enough to make it work.

 

[shortbus=]

The easiest/best way is to get the correct IC in the first place. In the end it takes much less board space and costs less to just use something made for the job. bipolar stepper driver ic - Google Search

 

[Triode]

Did you seriously just link me to a Google search? I've read and understand the data sheet for the L298. I'll just build it with flyback diodes on all the input lines and that should do it. That's all that any of the diagrams for other controllers I've found do. I've looked at some of the diagrams on CNC forums, they just don't typically work with a USB pic chip like mine so I wanted to see if I could get any tips about that specifically. But I'm sure it will be fine.

 

[shortbus=]

The L298 chip will limit the speed of the motor to around 140 - 150 RPM. If that will work for you go for it. Every one starting out wants to make their own drivers, but it's just not worth it in the end. The L298 also drops a pretty large amount of voltage too, again if you can live with that, go for it.

A dedicated driver chip has all the good stuff in it and is made to do just the one thing and does it good and simply. No code to screw with nothing but a easy way to do the job. If you look on the CNC forums, you won't see anybody returning to their posts and bragging about how good their home made drivers work. They all end up with a dedicated form of driver, especially for a bipolar motor.

 

[Triode]

I have every intention of using a ready made driver chip, or did you mean the controller? I could certainly use a controller like the l297 with this and I'm considering it, but that isn't really a big issue. What are you saying would limit the speed? The L298 can handle plenty of current and voltage and it switches fast enough.

 

[ducleboykuty]

how to do a circuit control dc motor

hello everry body
how to do a circuit to control a dc motor start in 15 minutes and then stop in 15 minutes
the delay time can show on led 7 segment
who are you can help me?

 

[Triode]

Ok, ignoring that unrelated post.

I'm still wondering why it would limit speed to use an L298 when it can drive the amount of voltage and current the motor is rated for, and why you act like im trying to design my own driver when I'm talking about using an existing driver chip. Is there something else I should be using, I'm here to learn. Do you mean an entire driver board?

 

[cr0sh]

Make sure when you use the L298, to use a properly sized and mounted heatsink with it, if you want it to survive...

 

[shortbus=]

@Triode- if the L298/L297 combination is such a good way to drive stepper motors, why is it that NONE of the commercially made devices that use a stepper motor use them? The idea that just because that combination of chips is a good one because it is found all over the Internet is not a good reason to use them.

Just about all of the posts about stepper motor driving problems on all forums is about "how can I make my L298/L297 circuit work?" Using one of the other driver chips eliminates the problems.

 

[cr0sh]

@Triode- if the L298/L297 combination is such a good way to drive stepper motors, why is it that NONE of the commercially made devices that use a stepper motor use them? The idea that just because that combination of chips is a good one because it is found all over the Internet is not a good reason to use them.

Just about all of the posts about stepper motor driving problems on all forums is about "how can I make my L298/L297 circuit work?" Using one of the other driver chips eliminates the problems.

Maybe he's a hobbyist who can't solder SMT components (yes, I know the L298/297 are available in SMT packages - but they are also very common thru-hole "DIP" devices as well, although difficult to mount on perfboards - I use special "adapter" PCBs from this guy that have worked well, though: **broken link removed**

I'll admit it isn't the best device combo, especially for a manufactured device - but then again, when you look up "h-bridge" and "stepper" on google, I would bet a fair percentage of the links go to tutorials on the L298/297 combo. If there were other IC combos (or just the h-bridge) that were thru-hole, that were better than the L298/297 (is there a better drop-in replacement for the thru-hole version, like the SN754410 is for the L293?) - I'm sure many would love to hear about it.

Got any suggestions? I would love to find a higher-power h-bridge, even if it's in a really large package - like this device I posted for help on here:

https://www.electro-tech-online.com/threads/looking-for-tec-ec-a063-datasheet.118217/

Not sure if such a thing exists (new or on the surplus market). I know that at a certain point, you have to go with discrete devices (MOSFETs) for higher-power h-bridges, but is there something out there for h-bridges between 4A and 10A, for instance? Is there a way to gang a couple of L298 (or work-a-likes) to do a similar job or increase the handling capability (I am pretty sure the 298 can't be paralleled, though I have heard the 293 being used/abused this way - but is there a way to use them in an unorthodox manner for this?).

I think more people would use other parts (especially those who aren't "designers of h-bridges") if there were some really good resources out there on the parts that do exist, and how to use them/combine them to create the systems needed for the hobbyist. Maybe then, we'd see a other chips become more prevalent? Then again, the electronics market doesn't cater to the general electronics hobbyist like it once did (which is a shame - not everybody has the skills or ability to handle SMT components).

 

[Triode]

Thanks, that was what I was trying to understand. I've looked at it more and there do seem to be chips that would work better, right away while looking for chips with the control and H-Bridge integrated I'm seeing the Toshiba TB6560 pretty often, which seems to have higher capacity and the controls are built in, would that be a better option or am i still missing something here? I think my misunderstanding was in terminology, wasn't sure if driver meant the chip that generated the pin combinations for steps or the H-bridge, I didn't know there were so many driver chips that did both. Is there anything else you can tell me to look for?

I can do smd components, but I prefer dip package ones so I can prototype a circuit and easily make changes.

 

[shortbus=]

The smd chips can be put on a board like this to work in a DIP socket; https://www.pololu.com/catalog/product/1201

 

[shortbus=]

Maybe he's a hobbyist who can't solder SMT components (yes, I know the L298/297 are available in SMT packages - but they are also very common thru-hole "DIP" devices as well, although difficult to mount on perfboards - I use special "adapter" PCBs from this guy that have worked well, though: **broken link removed**

I'll admit it isn't the best device combo, especially for a manufactured device - but then again, when you look up "h-bridge" and "stepper" on google, I would bet a fair percentage of the links go to tutorials on the L298/297 combo. If there were other IC combos (or just the h-bridge) that were thru-hole, that were better than the L298/297 (is there a better drop-in replacement for the thru-hole version, like the SN754410 is for the L293?) - I'm sure many would love to hear about it.

Got any suggestions? I would love to find a higher-power h-bridge, even if it's in a really large package - like this device I posted for help on here:

https://www.electro-tech-online.com/threads/looking-for-tec-ec-a063-datasheet.118217/

Not sure if such a thing exists (new or on the surplus market). I know that at a certain point, you have to go with discrete devices (MOSFETs) for higher-power h-bridges, but is there something out there for h-bridges between 4A and 10A, for instance? Is there a way to gang a couple of L298 (or work-a-likes) to do a similar job or increase the handling capability (I am pretty sure the 298 can't be paralleled, though I have heard the 293 being used/abused this way - but is there a way to use them in an unorthodox manner for this?).

I think more people would use other parts (especially those who aren't "designers of h-bridges") if there were some really good resources out there on the parts that do exist, and how to use them/combine them to create the systems needed for the hobbyist. Maybe then, we'd see a other chips become more prevalent? Then again, the electronics market doesn't cater to the general electronics hobbyist like it once did (which is a shame - not everybody has the skills or ability to handle SMT components).

@cr0sh- check this out; https://www.acroname.com/robotics/info/ideas/stacking/stacking.html#c

 

[RichTheDude]

The L298 is best combined with the L297 control chip, it should have no problem driving the steppers you have, but it will need cooling as the L298 will be at the top end of its rating, and it's a fairly old IC - so there will be quite a drop lost due to the L298's drivers.

https://www.st.com/stonline/books/pdf/docs/1334.pdf

The L297/L298 circuit act's as a chopper, and will apply whatever voltage it can to attain the desired current though the coil. To get speed (and high torque) out of stepper motors this is usually required (at faster step rates, there is less time to get current into the coil, as inductive reactance increases with the frequency), and the torque of the motor is proportional to the current.

Using the L298 on its own (in a voltage source type mode) would limit your step rate (and torque at higher rates) so I would suggest a chopper type circuit of some variety. This is why the L297/L298 combo is superior compared to just an L298 on it's own.

You will need to protect the L298's outputs from back EMF produced from the motors windings. I would suggest the L6210 as suggested in the data sheet, they are pretty small for 8 diodes. I would protect the motor supply with a fuse, and if you was super cautious you could isolate the driver board, perhaps using optical isolaters on the control signals - personally I would not bother.

Allegro Micro do a lot of stepper control IC's, which will feature more up to date drivers than the rather old but trusty L297/L298 combo. Microstepping is also common on such devices (a well known hobbyist site does modules for the A4983 IC (are links to shops allowed here?).