Replies

1. 
   kelvinpot | Mar 13, 2008 03:42pm | #1

   I think what you are hearing is the difference between universal motors, routers, skill saws, lunch box planers and induction motors. Induction is smooth and fairly quiet, i think the rpms are a lot lower for starters. Your router is going 10,000 rmps while induction is 1750 rpms or 3500 rpms. I think the drum sander will be fine noise wise. You can get a small 15" induction planer for pretty cheap and it will run circles around your lunchbox type. Last a lot longer as well. Check grizzly,i've had good luck with them.
   Have fun,
   KP

2. 
   saschafer | Mar 13, 2008 03:48pm | #2

   Induction motors hum, universal motors scream. The primary reason is that universal motors have brushes; that's where the scream comes from. Universal motors are typically smaller and lighter (and cheaper) for a given power capacity, but that advantage goes away at higher powers. For the most part, induction motors are fixed, single speed, while universal motors can be varied from near zero to very high speed. The top speed of a universal motor is also much higher--the maximum practical speed of an induction motor is 3600 RPM.

   There is also something called an electronically-commutated motor. Internally, these are most like universal motors, but they use solid-state electronics instead of brushes, so there is no scream. Electronically-commutated motors are relatively expensive, but you do see them in some kinds of variable-speed drives.

   -Steve

    

3. 
   RickL | Mar 13, 2008 05:12pm | #3

   Basically it's a router running a lunchbox planer. Typically it's 20,000 rpm and rhe speed is reduced to around 4,000 rpm or so in order to prouce the torque and horsepower needed.

1. 
   Bugsy | Mar 14, 2008 02:36am | #4

   Thanks for the insight guys,