Brushless DC Motors for spindles

[movingalong]

Hey guys,

I'm looking for some input on project that I'm working on, here are some details. I have been shopping for some motors to put on a couple of small spindles. I just need to run them at about 2700rpm, geared to the spindles at 2:1 ratio (~5400 spindle rpm). I have been looking closely at these motors from keling:

http://www.kelinginc.net/DCBrushlessMotor.html

Specifically the NEMA 34 sized ones.

I've never dealt with BLDC motors before, and wondering if a member here can enlighten me on driving these motors, and which power supplies are available for them and similar motors. It seems like a dc power supply that will run 48v and 55amps is going to be a little expensive. But that's just ignorance talking.

Thanks

[vger]

The 55 amp rating is the peak current rating. Nominal running current will be much lower. On driving these.... you will have to have a driver that is specificly designed to run a BLDC. It will have the 3 phase outputs for the motor and the inputs from the hall effect sensors in the motor. There are many available off the shelf or you can construct your own based on circuits like this one....
http://www.allegromicro.com/en/Produ...3930/index.asp

Some common brushless DC hall comutated motors you use right now are... the fan in your computer, the spindle motor in the hard drive, cd rom, and floppy. The ones you are looking at have a bit more power, but the drive method is the same.

Steve

[LUCKY13]

These guys have a drive that will work with the BLDC motors and there drive is who's I am going to use for just such a type motor.


good BLDC Drives



You also might look into Viper drives (do a search on the forum and you will find them).

Both Granite & Viper have sections in the forum to find more info about them. I really like one of the Grandie drives though because it can drive many different motor types, plus everyone that runs them just love them.



IMHO a BLDC motor is a better setup for a CNC build if reaching for best performance is the idea. They last longer plus they have more power with less inertia in a smaller package. I have never tuned a set but there specs speak for there self. You might look at Granites website for motors also, they have a few nice ones but they will not be selling them anymore after there stock runs out.


Jess

[Jason3]

I'm actually about to do something similar - I'll be using a servo for my spindle project, it will be direct drive though. I'm also using one for my Micro lathe build.

Granite Devices motors are servos, right in the middle of the Keling ones' range for power & torque, but are a smaller frame size. They have a higher voltage winding, so need less current. I think (not sure) the Keling BLDC motors don't have an encoder, but stand to be corrected on that. You could perhaps use a VFD to drive it, but if you'd like to control it with Mach3 then using a Granite drive and servo would avoid the need for a digital to analog interface.

If Granite Devices have run out of stock of their servos and you'd like one, please feel free to PM me

Best regards,

Jason

[blurrycustoms]

Thanks for all of the replies, I am working with Martin on this project, and this is good information.