Can someone tell me if I would need a braking resistor for my new CNC, and if so, how to calculate the Ohms needed for my 1.5 KW VFD? Also, where would be the most economic place to buy one? Also, do the sizes of my stepper motors affect the size of the resistor needed, or just the VFD? Thanks in advance for any assistance.
Short answer: You don’t need one. Only needed if you are breaking a load with a quick declaration ramp or a lot of inertia / power. If you go coast to stop mode there’s no breaking so no need at all. You can use the vfd for some breaking with out the resistor just watch your vbus doesn’t go to high. If it does it’ll trip and go to coast to stop anyway. Lengthen the deceleration time if this happens.
Ok, thanks Paul!
Haas uses electric stove elements for their resistors. Inexpensive and high wattage. Not sure what ohm.
Cool idea to use an electric stove element!