Phase converter???

[Jeff15]

Hi everyone, I run a few machines in my home workshop, I own a couple of phase converters one is a rotary (with motor) type the other a digital type that run two different lathes, a couple of years ago I bought a standby phase converter just in case, now I have another 3 phase machine 3hp motor that I need to set up, I got the coverter out wired a motor to it but it doesn't appear to do anything, the main box has a start stop button but also has another remote box attached with a speed control and start stop button.
When the start button is pressed on main board a breaker is activated and a sound of very quite humming a though things are working ok, however motor doesn't run, tried pressing start and stop on remote (stop does trip breaker then start re-activates it, but still motor doesn't run.
Anyone confirm what this actually is, am i missing something, maybe the motor is wired wrong? at the moment it has the jumper bars set to delta (the triangle sign) not actually tried it on the star setting.
I have however put a meter on the feed out of the box (motor feed) but there doesn't appear any volts across any phases.
Anyone any advise to try before I give up and buy another unit???
Pics are attached.
Regards Jeff

 

[ScottyUK]

It looks like some form of inverter. The two big blue capacitors indicate a DC link, and there are three switching devices of some form - either thyristor or IGBT /FETs - mounted beneath the board with the red capacitors.

My guess is that one of the switching devices has failed because they are subjected to the largest electrical stresses, but it could be anywhere on the PCB's. It has a distinctly old-fashioned appearance (1980s or '90s) and without a circuit digram fault-finding is going to be tricky, not to mention hazardous if you aren't au fait with power electronics and equipped with appropriate test equipment. There will be around 340V DC present on the big blue capacitors so be careful and allow plenty time for it to discharge before touching it. Obviously if you have a multimeter then you can carefully check for stored charge. You will quickly burn up money in labour charges trying to fix it, especially without circuit drawings. The good news is that the older through-hole PCBs are often repairable if you can find someone to diagnose the fault, and that most of the components look to be of Western European origin rather than obscure stuff from China.

Best bet is probably to watch on ebay for a second-hand variable speed drive.

 

[Jeff15]

Thanks for the reply scotty.
The unit was manufactured by a company called Glentronic Ltd in scotland, unfortunately not still in business (see new pic attached).
Not being an electrical techy when the unit is switched on should there be a voltage at the outgoing terminal block (where the motor wire is attached) even if a motor isn't attached??.
As you suggest probably look out on ebay..but thanks for your time anyway..J

 

[ScottyUK]

The Kompass directory lists ATB Laurence Scott at Norwich as a repairer for Glentronics equipment, and NDC turned up in Google. Might be worth a quick phone call, but on such a small unit the repair costs will quickly outweigh its value. Generally I wouldn't even consider repair on anything under about 11kW, although bear in mind that's my opinion as a commercial user rather than a home workshop owner.

http://www.ndc-uk.com/manufacturers.php?manf=Glentronic&bm=22#JUMP2

http://www.laurence-scott.com/products/control-gear/

FWIW I picked up a 15kW Allen-Bradley VSD for the lathe in my home shop from eBay - it cost under £50 excluding shipping. There are bargains to be had if you are patient!

 

[cranky108]

Are you sure there is a DC link? I've heard that using capacitors and inductors to shift the phase angle that it is possible to create a simulated three phase from a single phase.

I don't doubt that this will work, I just have never seen one myself.

So I suspect the two blue capacitors are shifting the AC one direction, while the two inductors are shifting the other.

 

[waross]

Looking at the picture, the nameplate rating of 3 - 60 Hz indicates that this is an invertor. You may change the phase angle but you cannot change the frequency with capacitors alone.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[cranky108]

Why would you want to change the frequency? The line frequency is usually very well set. Besides the term phase converter does not imply any frequency conversion.

 

[btrueblood]

The OP mentioned the box had a remote with a speed control on it, implying a VFD.

 

[ScottyUK]

Cranky, those are DC electrolytics. Phase shifting would need AC-rated film capacitors. Possibly I have the advantage of being familiar with the capacitor manufacturer!

 

[cranky108]

So electrolitic? Got it.

 

[waross]

Cranky; Take a look at this attachment from the OP.

http://files.engineering.com/getfil...sc=212727627.4.1480543505112&__hsfp=374225465

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Jeff15]

Thanks guys for all the replys..
Jeff