Re: DC versus 3 Phase

I am running my Shopmaster2000 with the 3 phase motors 0.75 kW (1HP)
from the beginning (ordered without motors and mount european 3ph)
because I have 3 phase outlet in my shop. The switches forward stop
reverse were 3 phase, only to wire them properly.

I plan to add VFD in future (still rather expensive for me). I asked
some VFD suppliers and they recommended me:

1. Use motor that is VFD rated. You can also use optional output
inductance that eliminates long wires and HF noice on motor.
(expensive) It could be also good for older not VFD rated motors.

2. For lower speed use external ventilation!!!

3. Buy optional input filter to eliminate noise to power line.

4. Use upper frequency max. 100-120 Hz (depends on motor). With higher
frequency lower torque.

5. Use lower frequency down to 5 Hz (scalar control VFD), down to 1 Hz
(vector control VFD) with rated torque. Some vector control VFD can
run up to twice rated torque at lower frequencies.

6. Buy external braking resistor if you want to stop motor more
quickly.


Alex