AC Variac

Tom Militano

Feb 27, 1999
I know my way around a machine shop pretty well, but electronics are a total different world to me. Do any variacs come set up for ac input and dc output? All the variacs I've seen on e-bay have ac output. Do you have to run them through a bridge rectifier to change to dc? Can a variac be used for a speed control on a dc motor. Thanks.

[This message has been edited by T. Militano (edited 05-23-2001).]
Tom, a friend of mine made an anodizer for me with a variac. Yes it comes out AC and must be ran through a bridge rectifier which converts it to DC. Mine is 0-140 volts. Plenty of power. I never turn it up on high end or else it boils and etches titanium. It may still have a few bugs to work out. Bruce B
I took a bad fall and can't move my right foot, can't even wiggle a toe. I have a lot of damage from bulging discs, spurs, compressed discs, a damaged sciatic nerve and they can't operate due to the condition of my lower back, twenty years of fun in the military. Have to use crutches at present. The fall caused more damage, bruised a nerve, and the doctors said it will probably not heal, so it's probably a permanent condition. I'll just start grinding sitting down. I've had a lot of fun getting in this condition though. I'm still going to the Blade Show on Saturday, if I have to slither around like a snake. My wife and son will be with me and they can carry the supplies I need to replenish. Is 5 amps sufficient to control a dc motor? Do variacs come for 220 volt single phase applications? See you at the Blade Show?

[This message has been edited by T. Militano (edited 05-24-2001).]
Tom Sorry to hear of your health trouble. Yes 5 amps is enough. 220 isnt neccesary. Mine is 115 volt and its plenty powerful. The mini anodizer that Reactive Metals sell is a 4 amp 0-200 amp I beleive. It works great I hear. See ya at the blade show. Bruce B
I just got lucky and won a new, unused 120v or 240v variac off of e-bay for $27.00. All I need to do now is get a friend of mine, who works in electronics, to wire it up and add the bridge rectifier and I should be in business. Thanks for all the feedback.
It's pretty easy. Johnny Stout drew a pic on the back of a napkin for me and I had no trouble soldering the rectifier to the 4 leads and attatching the alligator clips.

Arthur D. Washburn
ADW Custom Knives