DC motors?

[Daniel Rohde]

Is there anything special or better about DC motors?

What do you need to run one?

Thanks

 

[Bo T]

I've read that in some cases a DC motor is smoother than an AC motor. Most will use an Variable speed SCR controller to drive the motor. Usually, for knife grinders, they will convert 120 V AC to 90 V DC or 220 AC to 180 DC. With the advent of the newer AC speed controllers for 3 phase AC motors there doesn't seem to be much advantage for the DC motors. When I calculated the costs for a 1.5 HP set up it was pretty much the same for both.

 

[Stacy E. Apelt - Bladesmith]

In the past, what DC had going for it was speed control on 120VAC single phase power. Also, DC motors are normally sealed units, which is a plus in a metal grinding shop.
Now, with affordable 3Ph speed controllers that run on single phase, and cheap used TEFC 3Ph motors, DC isn't the only game in town anymore.
I still like DC for its simplicity, but 3Ph is probably easier to use in larger motors. I have both on my equipment.