eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
So having recently picked up the 25 H.P. Baldor VFD from my other thread, I've been thoroughly reading the manual and discovered that a series 15H, "E0" drive has no dynamic braking hardware. It will do DC injection braking though. My thinking has been in the direction of just repairing and using the lathe's mechanical brake and not worrying about that.
However, reading up on the subject has gotten me interested in how exactly it works. There are two terminals at the terminal block labeled 'B+' and 'B-' that I assumed were connected to the DC bus and that seems to be the case, as the voltage reported by the drive as 'DC Bus Voltage' and the voltage at those terminals is the same. There are also two terminals that are related to the braking labeled as 'D+' and 'D-' that I'm not sure about. All four are to be connected to the external braking transistor and resistor, along with their grounds of course.
How hard would it be to create my own external unit just to do it for the experience? I'm fairly well versed in basic electronics and have created other circuits, repaired plenty of surface mount and through hole electronics, etc. Seems like it shouldn't be too complicated, to simplify it, just have to figure out how to drive the transistor so it activates the output to the resistor once the voltage on the DC bus hits 380V then shut it off after it drops down to 360ish.
However, reading up on the subject has gotten me interested in how exactly it works. There are two terminals at the terminal block labeled 'B+' and 'B-' that I assumed were connected to the DC bus and that seems to be the case, as the voltage reported by the drive as 'DC Bus Voltage' and the voltage at those terminals is the same. There are also two terminals that are related to the braking labeled as 'D+' and 'D-' that I'm not sure about. All four are to be connected to the external braking transistor and resistor, along with their grounds of course.
How hard would it be to create my own external unit just to do it for the experience? I'm fairly well versed in basic electronics and have created other circuits, repaired plenty of surface mount and through hole electronics, etc. Seems like it shouldn't be too complicated, to simplify it, just have to figure out how to drive the transistor so it activates the output to the resistor once the voltage on the DC bus hits 380V then shut it off after it drops down to 360ish.