Running stepper at higher voltage

[Biggs427]

My machine have 1.6mH (X and Z) and 1.8mH (Y) steppers.

Using the Gecko formula sqareroot(mH) * 32 this gives 40v and 42v. Is this max voltage? target voltage?

My drives can handle more so what would happen if I use a bigger PS; like 60v?

Similar Threads:

• advice on voltage and amps to run higher RPM
• Stepper Squeal/Whine at higher voltage ... So close, but yet so far
• Able to run motor with higher voltage driver?
• Does higher voltage allow steppers to move faster?
• Capacitor at higher voltage?

[109jb]

The formula gives an optimum voltage. Higher than this and there is minimal return regarding performance. Lower and the performance will suffer. Higher will also mean increased heat though too.

[ger21]

What voltage are you using now?

[Biggs427]

40 volts

[ger21]

If the motors aren't getting hot now, then 60V might get you 30%-40% more speed, at the expense of hotter motors. But it's hard to know for sure until you try it.

[Biggs427]

Would this help acceleration too?

[NIC 77]

Would this help acceleration too?

Yes. The torque that is available at your max speed determines the acceleration you can get. Some programs have two inputs for acceleration, one for rapids, and one for feeds, mach 3 does not. So if you're using Mach 3, then your max acceleration either for rapids or feeds is determined by what torque is available at the fastest speed your motor turns.

At the high RPM range of your stepper, a doubling of the voltage doubles the torque. At the low side of the RPM range, the torque is about the same.

[ger21]

It's not quite a simple yes or no question.

Say you have a 250oz motor, where the torque drops to 100oz at 1000rpm.
You're acceleration rate up to 1000 rpm is limited by that 100oz of torque.

Now, you raise the voltage top 60V, and you now have 100oz of torque at 1500rpm.
If you want to now run your machine 50% faster, you're acceleration is still limited by the 100oz of torque you have at your max speed.
If you want to accelerate faster, you'll need to lower your maximum speed. You can do the same thing now at 40V. Lower you're rapid speed, and you can increase your acceleration.

The real issue is that hobbyists and DIY builders rarely (if ever) design their systems and buy their components based on specific performance goals. They buy what everyone else buys, what's readily available, or what's cheapest. And then try to squeeze every ounce of performance out of it, which is the real issue. For a reliable stepper system, you really want to have at least 25% of reserve power, to overcome the variety of issues that can potentially cause lost steps.

[Biggs427]

... you really want to have at least 25% of reserve power, to overcome the variety of issues that can potentially cause lost steps.

When I configured my controller, I did some tests and determined that the max rapid speed I could achieve with my machine was 590IPM for Y and 610IPM for X axis.

I set my rapid to 400IPM so roughly 33% less than max speed. Is this the reserve power you're talking about?

[ger21]

yes