I have a friend that's a master electrician. He was cleaning up his office today, and gave me some old stuff.

The one thing I got I know fairly little about. It's a Magnatek GPD 503. He said it's 3 phase, but thought I could put in a normal wall cord and run a 3 phase motor. It appears it's rated 300-500V 3 phase. Seems without a lot of extra gear it's not much use.

I'm not even sure it works. I like his idea, but I doubt that's possible, I was thinking maybe it could work as a signal generator of some sort if I can find a way to get 120 to run it and somehow isolate the output.

 

That is a VFD, Variable frequency Drive for a 3ph induction motor, some can use 1ph input and out put 3ph, but that is most likely a 10-15hp model, if so it it too large for 1ph in.
Also being a 300v model you may have problems trying any output on 240v 1ph.
If it does fire up, you may have luck running a smaller 240v 3ph motor.
If it works, there may be a lucrative market for it?
Max.

 

They seem to sell from $300-500. It had the cover off when I got it. I gave it a look see if could see any signs of issues, other than some dust i didn't really see anything.

 

That's a rebreanded yaskawa drive, top of the line. Maybe worth a few hundred bucks if works, But it's probably 15+ years old. It probably doesn't take single phase input, although some models of the GPD do, they are not common. Most of them do however take a DC input. So if you had a step-up transfermer and rectifier, you might be able to use it.
here's the manual:
https://www.yaskawa.com/pycprd/look...1W9ROOa-FJQutNOPOdvUZ6CWgC782P7F_3ohoAfFdnl68

and several more info about gpd503:
https://www.yaskawa.com/pycprd/prod...al-purpose-drives/g3-gpd503-drive/tab1/link10

 

It could be nice to use, but from looks of the manual i'm missing some choke type things for the in and out. Then also need transformer to step up and change phase.

Here is a manual: http://igor.chudov.com/manuals/Yaskawa-GPD-503-Manual.pdf

The label on it says this: Input AC 380-460V 50/60HZ 3Phase 14.9A. Output: 0-460V 0-400HZ 3 Phase

Variable torque continuous 13.5A, constant torque 12A.

If it fires up it may be better just sell and possibly see if there is something similar but something I could use better.

 

You don't need those reactor ("choke type things") in most cases. They put them in the manual so that when you blow up the drive and send it in for warranty work, they ask "did you use the reactors? No? "

 

Most manufacturers recommend a 3ph inductor or choke on the input or output, but the VFD will work without it, the one on the output side is to reduce switching noise and make it easier on both motor and drive, especially if a non-vector rated motor is used.
Max.

 

Thinking it could be cool for driving a tesla coil. Then don't need spark gap, etc. Giant solid state driver for a coil.

 

As a word of caution, an inverter can be used only with an "inverter compatible" motor.

A motor intended for use with ordinary 60 Hz. commercial power will eventually suffer an insulation failure due to leakage current from the stator to ground.

 

That may be true in a 24/7 situation, but there are uncountable VFD's out in the real world happily using them on non-inverter motors.

 

As a word of caution, an inverter can be used only with an "inverter compatible" motor.

A motor intended for use with ordinary 60 Hz. commercial power will eventually suffer an insulation failure due to leakage current from the stator to ground.

I have been istalling VFD's with non-vector rated motors for some decades now, the oldest was a 1950 motor, so far had no failures, the only precaution is I usually maximize 4 pole motor to 120Hz.
If nervous of using one then a 3ph inductor on the motor side will ease things considerably.
Max.

 

Well here's the manual for it and if I am reading it right that particular model is a monster! 75 - 100 HP capacity!

http://igor.chudov.com/manuals/Yaskawa-GPD-503-Manual.pdf

Looks pretty straightforward to hook up and test. Now if it does work and you can get a buyer a VFD that size and brand out to bring you $1000 or more easy even as an older unit!

And no it will not work for a tesla coil driver unless you gut it and plan to just use the massive power supply and switching devices only. The actual electronics that control it will never let it work as anything else but a 3 phase motor drive.

 

Well here's the manual for it and if I am reading it right that particular model is a monster! 75 - 100 HP capacity!

That is just the general series, they start at 1hp in that model.
Max.

 

According to the manual for it this unit (the DS316 model) will run a 7.5HP motor. Says 10.2A at 460V.

It looks like it has a switching mode supply in it to run all the logic. I'm thinking it probably hooks into either a 120 or 220 poles. I'm not 100% on how three phase works i'm thinking it's like the 220 range plug. You have a neutral, and two hot. wither hot to neutral makes 120, hot-hot makes 220. Seems to me the 460V rating would have to be a combination of like a pair of 220 or something.

I suppose I could probably always bypass the SMPS too and put in some power from something else and see if it powers on.

It looks like it was used because appears fan blew in dust. Only knockout on it though is on the side of the plastic cover which seems odd.

 

According to the manual for it this unit (the DS316 model) will run a 7.5HP motor. Says 10.2A at 460V.

It looks like it has a switching mode supply in it to run all the logic. I'm thinking it probably hooks into either a 120 or 220 poles. I'm not 100% on how three phase works i'm thinking it's like the 220 range plug. You have a neutral, and two hot. wither hot to neutral makes 120, hot-hot makes 220. Seems to me the 460V rating would have to be a combination of like a pair of 220 or something.

I suppose I could probably always bypass the SMPS too and put in some power from something else and see if it powers on.

It looks like it was used because appears fan blew in dust. Only knockout on it though is on the side of the plastic cover which seems odd.

No neutral used in general for VFD hook ups, whether 1ph or 3ph in.
The general rule 1 ph input can be used for anything 5hp and under.
Max.

 

Okay. Any idea then of how a single phase would hook up, do I need the full 460V then? It looks like has 3 screws for in 3 for out and a pair for a DC bus for something. Has others on control board, but they seem to be sensor type things.

 

Single phase input is usually detailed by the particular manuf, they do not all conform to one single method, e.g. some require two particular phase inputs for the 1ph pair, usually because of the control voltage take off, also the 1ph versions are predominantly 240v, probably because of the rarity of a 460v 1ph service.
I suspect you need a full 460v, not only for the P.S. capacity but the low voltage control circuitry may be affected.
It may be a question of hooking it up and experimenting, there are generally many safety features included and if the display lights up, may give you a certain fault msge if it does not like anything.
Max.

 

Okay. I looked at the power/terminal board. I figured out where part of the SMPS line in comes from, but not sure yet where other side of that goes. It seems to go back to one of the phases, but that also links to 2 transistors used by the DC input. A normal hookup for this seems fairly simple, but has DC bus, some other DC thing the manual is calling a DB unit.

Looks like got a bunch of stuff ti figure out on this.

 

DB maybe Dynamic Brake?
Apart from the control circuit, most just input the 3ph or 1ph directly to a bridge rectifier.
Max.

 

Most VFD's that size will work on single phase if they are powering a smaller motor or if the main rectifiers are replaced with higher amp ones and the main power capacitors have an extra set added externally they can usually work well at full power.

I have a few 460 VAC units that I have used that way before and just used a common 115/230:230/460 isolation transformer setup as a boosting auto transformer to get 480 VAC single phase from my 240 VAC power. I just set them up with the two 115 secondaries as extended parallels of the 230 VAC primary winding configuration turning the 120 - 0 - 120 supply into a 240 - 0 - 240 system.

Given that if it's only a 7.5 HP and it 460 VAC that brings the price down a lot. I typically buy good used ones on eBay for under $50.