3 phase monitor

Hey Guys,
While working on a machine the other night I found that we didn't have a 3 phase monitor in the shop when I needed one. I know there are plenty of them on the market and they are fairly inexpensive, except when the employer doesn't want to spring for one. So now the big question...does anyone have a diagram or info on homebrewing one? Thanks for any help.

Waggs

Can you be more specific on what type of monitor you need?
Phase rotation
Power meter
Phase loss

Hey Jim,
While a do all would be nice I'm really just looking for phase loss. But it would be interesting to have rotation along with it. I have one laying around somewhere but being a tinkerer I thought it would be fun to build one and understand just how they 'do' what they do. Thanks for the reply Jim!~!~!

Bob

Timemark in Oklahoma makes some good units that I've used for years.

You could suggest to your boss that the alternative is putting two 480 volt coil relays across phase A-B and B-C and placing the contacts in series, and show him how that is more expensive than a phase monitor.

Do a cost analysis. How much would it cost you to make a phase monitor. How much would it cost to repair a machine that didn't have a phase monitor on it. How cheap a phase monitor really is.

By the way, the SymCom 250A is my phase monitor of choice, I've had too many Timemarks blow-up during a lightning storms.

How ya been Buddy?

I think I know why you want to build one.

The Time Mark and others are easy, three flying leads with alligator clips, color coded of course. Fast for monitoring rotation and loss.

So, would you want it for Wye or Delta? Or both?

Now, to reinvent the wheel....

73 kc

Here's something neat.
http://www.grace-eng.com/VoltageVision/DS-R-3W.shtml
Not exactly what you're looking for, but......

Rube: Yeah, I've used some Timemark units in the past. Handy but not quite what I'm looking for.

Alaric: Although proving something to my boss would be of immense personal pleasure he doesn't have any idea what it would be I was trying to prove to him.

Tark: I haven't seen the SymCom units yet...will have to dig into them. What I am really looking to build is just a simple one that attaches with alligator clips. Its really more an exercise in building and learning as I already have one stowed in the kit bag at home...I refuse to take it to work.

Casey: Hey Dude, like minds think alike, don't they?...hahaha. Yeah the tinkerer in me says, 'build the stupid thing'. You guessed right. It would be needed for wye-delta. Btw, I've...mmm...changed industries. Now back in injection molding. Will PM ya more about the change.

olias: That is a neat little unit...I haven't seen that before. If I get a chance to recommend something along that line sometime I will take a closer look at it.

Thanks to all who responded...much appreciated.

Waggs

I've seen/used very small 3 phase motors with a little disk on the shaft to show direction and the alligator clips.

I usually just use a dual trace o'scope - not viable for your use though

rod