[samim]

The G540 can be powerd with 18VDC to 50VDC supply voltage.

If the motor is rated at only 3.4VDC @ 2.9A, what is the advantage of having higher volt power supply?

Are there other stepper motors which operates at much higher voltage ?

Thanks

[ger21]

RPM is proportional to voltage. The drives need higher voltage to keep the full rated current flowing at higher rpm. Most steppers can be run at up to 20x their rated voltage. If you know the motors inductance, the ideal power supply voltage would be 32 times the square root of the inductance.

[samim]

My Dahlren is so old, I dont know what the inductance. According to the manula, it has high torque stepper motor through 5/8" dual lead 4TPI lead screw, dual ball bearings.

No sure if that helps.

Thanks.

[Richards]

Old motors can be a problem. Look around the various stepper motor manufacturer sites and try to find other motors that have similar specifications. For example a modern square type 23 frame size motor from Oriental Motor that has similar specs is the PK268-03A that, when wired unipolar, has 3V and 3A. It has a unipolar inductance rating of 2.2mH, so I would try a power supply of about 35VDC to 48VDC. (The higher the voltage, the hotter the motor).

In any case, start at the lower end of the voltage range and work up. I use a Variac to adjust voltage going TO the transformer. The Variac lets me try almost any voltage. By starting low and giving the motor plenty of time to temperature stabilize between settings, you could find a voltage that works for you.

Be sure to run the motor with a regular load on it to simulate the actual conditions of the finished product. I like a motor temp of 65C or less. Motors can run a lot hotter than 65C, but I'm kind of conservative. I just don't like the smell of hot electronics.