Several Questions

[DistortedDesign]

Hi, I have some noob questions. I am about to start my Joes 2006. I haven't been on the forums in about 6 months. I have been waiting on funds so I could finish buying everything I need to build my Joes. My memory is a bit foggy so I could use a bit of refreshing.


What is the wiring you can use to get extra power out of your motors? Is it wiring unipolar motors with a bi-polar controller card to get the extra power?

Is there a way to use a uni-polar controller card like hobby cnc with bi-polar keling motors? Keling has the best prices on motors I have seen. I already have a hobby cnc kit. I know they say that you can't use them but I wanted to refer to you guys first.

Reading the hobby cnc kit it says that you need double the rated amps per motor for running. So if you are going to run 2.5A per motor, they said that you need 5A per motor. So instead of only needing a 24V 7.5A power supply, I need 24v 15A power supply?? I haven't read or seen anything on here about that.

I am looking a 400- 425oz motors, what kind of power (amp/volts) should I have for this setup?

Ohhh and a FYI Keling power Supplies are WAAAAAAYYYY over priced. I found the exact same power supplies they have for 1/3 the cost at MPJA.

[DistortedDesign]

Ok, I am confused...... I just looked closer at kelings website and the 425oz motor data sheet. According to his part number and the explanation at the bottom of the page it is an 8 wire bi-polar motor???? Is that even possible?? The data sheet shows the data for the motor wired in uni-polar, bi-polar parallel, and bi-polar series......

[ger21]

8 wire motors can be run unipolar, bipolar parallel and bipolar series. Bipolar gives more torque than unipolar, about 30% more. Bipolar parallel gives higher rpm's.

If you're using the HobbyCNC drive, you'll get the best performance running at around 36V. Not sure about current with that drive.

[DistortedDesign]

Does anyone know how many amps you really need for hobby cnc with 425 Oz keling motors? Right now I have 24v 6.5A power supply, is that enough? Do I need to get another one and run them together so I have 17A?

[DistortedDesign]

Anyone?????

[Crevice Reamer]

First of all, a stepper motor gives it's maximum torque when standing still, and it goes downhill as the speed increases.

Just because a motor is rated at 425 oz doesn't mean that that motor is more powerful than one rated 280 oz. The Keling 425 will give that much torque only when wired Bipolar parallel and powered by 83 volts. If you use this motor unipolar and powered by 36 volts, it will probably not give you HALF of that torque. running it with 24 volts would allow even less.

The formula for best-performance motor voltage is 32 times the square root of the motor inductance in mH.

You have to do more than just compare torque ratings. You might be ahead by just selling the unipolar card on ebay and buying something that will allow Bipolar Parallel wiring and a higher voltage power supply.

CR.