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Topic: Can you recommend the right motor shield for my stepper motor? (Read 2173 times) previous topic - next topic

HitzzFromTheGong

Hello and thank you for taking timeout to ponder my problem.

I am using a Arduino Uno r3 with a Nema 23 Stepper Motor 23HS41-1804S. The motor needs 5vdc and 1.8amp current to run properly. I have tried a couple of shields however when I find one that can handle the current it needs more volts than the 5 I have running to it. The motor will be running often for the application so it is important that the shield can handle the current for long periods.

This is a low current stepper motor but low current google searches on a stepper shields brings up specs that don't match up. Is this a common problem?

I have purchased and returned a number of shields due to this problem. I have limited access to online resources as I can only use the internet on off peak hours 2amto 8am. This makes my trial and error even more difficult. I am doing my best to understand this new hobby any help on this matter would be greatly appreciated. Thanks and be well.

c0rsa1r

You should get something like the Synthetos gShield (grblShield) V5.

This shield is used on a CNC motion control system, providing 2.5 Amps per winding with a 12-30 Input Voltage (that means you MUST have an external power supply, but that is MANDATORY for almost every motor).
"The S2000 is nothing so much as a legend in its own time. If you don't like it, you probably haven't driven it hard enough." - Car culture

HitzzFromTheGong

Thank you for your reply. My power supply is 5v 1.8amp  the same as the motor. Will that work?

c0rsa1r

I would use a power supply able to provide at least 20% more Amps than my motors need on max load.

It should work anyway, but I wouldn't do that.
"The S2000 is nothing so much as a legend in its own time. If you don't like it, you probably haven't driven it hard enough." - Car culture

HitzzFromTheGong

I have a CNC V3 Shield that has a voltage of 7-24 volts with TI DRV8825 StepStick Stepper Drivers that are rated for 2a. Would that work if I raised my  power supply?

MarkT

1.8A will run the DRV8825 pretty hot - definitely need heatsink and preferrably a little fan.

What exactly do you want to do with the motor?  How fast do you want it to turn?

Stepper motors are current rated, not voltage rated.  Your motor is 1.8A and 2.75 ohms,
the voltage needed depends entirely on how fast it turns, and might be upto 48V or even 80V
for a super fast system...

Lets repeat that important point:

Bipolar stepper motors are _current_ driven, not voltage driven.

This means H-bridges are the wrong choice (unless you only need very slow movement, and even
then they are usually the wrong choice because they are darlington drivers) 

Constant current chopper drives are the right choice.  Upto around 1.5A small single-chip
choppers like the DRV8825 and A4988 are possible.  From 2A up you really need discrete
MOSFET stepper driver, which gets more expensive, but will run cool and are available upto 10A.

The voltage of your supply depends on how fast you want the motor to turn, and how low its
winding impedance (mainly inductance) is.  Some experimentation may be required - but definitely
go for microstepping if at all possible, reduces vibration and miss-stepping.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

HitzzFromTheGong

Thanks for your time. I am using the motor to connect to a bass drum pedal to make a gong ring. This needs to be a repetitive back and fourth motion for 4-7 minutes per session. I do have heat sinks for the DRV8825's. I dont need a ton of speed just fluid even movement. Lets say I run 24 volts on my power supply how will the drivers get the 1.8amps needed? 

Robin2

Lets say I run 24 volts on my power supply how will the drivers get the 1.8amps needed? 
If the 24v power supply can provide more than 1.8 amps the question should be "how will the drivers NOT get the amps needed", or, nore seriously, why do you think there will be a problem?

...R
Stepper Motor Basics
Two or three hours spent thinking and reading documentation solves most programming problems.

MarkT

Thanks for your time. I am using the motor to connect to a bass drum pedal to make a gong ring. This needs to be a repetitive back and fourth motion for 4-7 minutes per session. I do have heat sinks for the DRV8825's. I dont need a ton of speed just fluid even movement. Lets say I run 24 volts on my power supply how will the drivers get the 1.8amps needed? 
So how fast does the motor have to turn?  Numbers please, not nonsense like 'don't need a ton of speed'
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

HitzzFromTheGong

I apologize for not responding right away I have not had access to the internet. I am not exactly sure how fast I need the motor to run as the project is a prototype to replace my labor of playing the gong/instrument. I don't hit the gong very hard but I am sure it will take some tinkering once i actually get the motor running and program the motion needed.

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