6 wire motor options

[Ross77]

Thanks Gary

Always over thinking things :0)

I was looking to use this as bit of a test bed to learn Linux as well and it seemed like a good idea. As long as it will mill pcbs then I'll be happy.

[Ross77]

Had another look at the machine today and noticed that the stepper is 1.65v and 4.7A, will it matter that the drivers are only 4.2A peak?

I bought the Gerber engraver and 3 vinyl plotters as a job lot and they all the same make of stepper. I have another motor that is higher voltage and lower current, would that work better?

[john swift]

the other factor you need to take into account is the inductance of the motor coils

the higher the inductance , the longer it takes for the motor current to reach the current the stepper driver is set to

this delay will reduce the speed you can step the motor

by using higher stepper driver supply voltages you can speed up the increase in current
the heat due to the copper & iron losses as you increase the voltage is the limiting factor

as a guide to select the supply voltage

multiplying the square root of the inductance (in mH) by 32 = stepper driver supply

for 2.2mH coils

32 x 1.48 = 47V


for 5mH coils

32 x 2.236 = 71V


using a stepper driver at its 4.2A limit
to drive a 4.7A motor will reduce the motor torque to 89% of its maximum

John

[Ross77]

I cant find the specs for the exact model but looks like my best option is to go for full coil as the current will drop to 3A, which is within the driver spec. ideally I should double the voltage to 60V but the drives are 50V max so will try with the original 30V (tested today and its 30V not 50V as first thought) and see how it goes.

[m_c]

Try it and see.

You'll most likely find the original motors were not driven at maximum voltage or current, and even if they were, you'd just need to a tune everything a bit slower. However, you'll most likely find fitting modern drivers will give a performance boost anyway, so even at less than maximum voltage/current, you'll most likely be able to get better performance.