Diy Brushless Spindle

[paul.hunaban]

I want to change out my wood router for a brushless spindle as I’m having to replace the brushes all too often.
What you guys have done here is very interesting but I’m not sure how to size the motor / what motor to get.
Therefore I have a few questions:
Q1, if the RPM/v is rated at 295 does this mean for every volt it will increase by 295 revs, i.e. for 20v the speed would be 5,900 revs?

Q2, would you read the power output in the same context as you would a wood router, i.e. if both were 1000w would both be deemed to have the same output?

Q3, Any recommendations for motor to cut wood (Oak) ? At the moment I do a lot of 3D profile work thus cut at around 2.5m per min.

Q4, should I give any consideration to the speed control other than it meets the spec of the motor, ie is there a rule of thumb for the control to have say a 10% high power rating?

Many thanks in advance Paul

[Jonathan]

1) Yes that's right.

2) Hard to say - the ratings for the brushless motors are a bit optimistic since they assume excellent cooling from the very high airflow present in a model plane. What power rating the motor is will be dictated by the speed rating since 'hobby' brushless motors with a similar kv specification tend to have similar power ratings. That's unless you introduce a belt into the system...or couple multiple motors on one shaft, but that's probably taking it too far for machining wood.

3) Clearly depends on the tool diameter, but I'm guessing you'll want about 12000rpm for oak? So look for a motor with around that speed rating. Ideally you don't want to have to use 'high voltage' (i.e. above 25V) ESCs as they're very expensive. So roughly 12000rpm/25v=480kv, or more if run from a lower voltage...

http://www.hobbyking.com/hobbyking/s...ner_Motor.html

Your next problem is the shaft diameter - the one above is only 6mm which makes it a bit useless unless you have a lathe to modify/make a collet chuck...

5) Easier to advise once the motor is chosen, but it's sensible to get a bigger one than rated to be sure. They're pretty cheap from the site I linked to above.