Hi,
I suspect that the real reason that your steppers can't go as fast as you want is because they have too high inductance (3.8mH).
The lower the inductance the faster the stepper can go before it loses torque and stalls. Every stepper loses torque the faster it goes.
A 23 size stepper with 1mH inductance will retain about 40% of its torque at 1000 rpm whereas a 3.8mH stepper of the same size might have only
10% at 1000rpm.
To be honest I doubt the 34 size steppers will be any faster than what you have. Sure they have a lot more torque at slow speeds but what about at 1000 rpm?
Manufacturers of steppers know that first time buyers don't know about inductance so they make cheap high torque steppers but with such a high
inductance that they can ONLY be used at low speeds. Don't be duped out of your money.....you need LOW LOW LOW inductance.
For 23/24 size steppers get 1-2mH with 1mH preferred and reject anything over 2mH.
For 34 size steppers get 2-4mH with 2mH preferred and reject anything over 4mH.
The classic way to overcome inductance is to use the highest possible voltage driver and power supply you can get. At the current time Gecko's (the
gold standard for performance and reliability) are rated to 80V. Leadshine AM882's are also rated to 80V and quite a bit cheaper than Geckos.
To me it matters not whether you have a driver that accepts AC (it rectifies and smooths that to produce DC) or one that accepts DC only, the only difference
is the voltage available to drive the stepper, the higher the better. My Vexta 5-phase stepper drivers accept 230VAC but rectify and regulate to 150VDC to drive
the steppers. With 150VDC up their chuff they spin at 2400rpm no trouble!
There are some advantages of closed loop steppers but not enough to justify the expense. The manufactures claim that they go faster and have more power.
That's ABSOLUTE RUBBISH. They are when all said and done ARE STILL steppers, they lose torque as they go faster. A closed loop drive DOES NOT CHANGE
the physics of stepper motors. The manufacturers are using a bulls****t line to get your money.
If you really want closed loop performance then get AC servos, don't waste your money on closed loop steppers. Delta (Taiwanese manufactured in China) or DMM
(Canadian manufactured in China) are two very good brands that won't break the bank. There are even cheaper Chinese AC servos much less well known and of less
certain quality and support but at the price they beat any stepper ever made.
Craig