Lathe and phase convertor

[addjunkie]

before i got side tracked rebuilding a farm house, i purchased a 3 phase lathe. Then a phase convertor from traswave. Well as i said i got side tracked. 2 years later,,,,, And today i had a play.

Wired up phase convertor, and plugged it all in, green light comes on, and the motor sounds like its trying to start, but doesnt. The boost light never goes out and phase 2 sits at 200 volts.

Head scratch time, any pointers greatfully recieved. Have a funny feeling that the control circuit is wired from L1 and L2, and as L2 is the manufactured phase its not closing a relay.

No wiring diagram doesnt help!

 

[MattH]

As you say the control my not be across the correct phases.
transwave specify that all control circuitry must be hooked up to two particular phases. They say that the symptoms of being in the wrong pair will be that the motor doesn't start or the controls will cycle.

Just try swapping L1 and L2 around, if that doesn't work then swap L1 and L3.

 

[addjunkie]

Swapped L2 to L3 after some head scratching as wire numbers, etc dont match drawing, no surprise there, with imported machine.

Motor turns but doesnt reach full speed and trips....to be further investigated. Switched lathe to lower speed selector, its a two speed motor, and spins up no problem starts stops and reverses as it should, with the bost switch at no 2.

Back to high speed messed about the boost settings, sometimes reaches full speed sometimes doesnt, the trips, when it does no matter where i move the switch it sounds awful, bit of a pain to to have to mess on with another switch when starting lathe.

Any ideas? Im at about the end of my electrical knowlege.

 

[MattH]

Is it a static convertor?

 

[addjunkie]

Yes

 

[MattH]

You might need a rotary converter with a dual speed motor. If you have an old 415v motor you can add it inline to converter your static to a rotary.

 

[addjunkie]

Looks like i need to do far more research, motor shouldnt be an issue, think i know where there is one, from the instructions i think it needs to be similar size?

 

[addjunkie]

Well been to shed for another play, with someone to start and stop machine while i investigated fiddled with settings,

Now have all 12 speeds, top 6 need boost at 5,6,or7 depending on the speed, then once at speed turn it down to 1 or 2 depending on the speed. Bit of a pain, but can live with it, now i know what settings to use, had to tweak over load relay up 1/2 an amp.

Dro and coolant pump even work.

Now all i need are some coolant, a coolant nozzel, and some new cutting tools. And of course something to turn. But im happy mill and lathe now both working only been here 21/2 years.

Thanks for your help

 

[wilbur]

Static phase converters can be a bit hard to get started. Back in the 80s, a neighbour of mine had to build a 3 phase coolant pump for his milling machine so that he could start the pump first to get the phases spread out enough in the converter that he could then start the milling machine's main motor.

 

[addjunkie]

If i do this again, i shall be looking at Variable frequency drives, far far cheaper. I like cheaper.

 

[JohnRUFC]

http://www.britishblades.com/forums/showthread.php?77227-How-to-wire-up-an-inverter-Properly

Have a quick read there.

 

[MattH]

http://www.britishblades.com/forums/showthread.php?77227-How-to-wire-up-an-inverter-Properly

Have a quick read there.

LOL, love articles like that.

"How to properly"! No RFI filter as per manufacturers instructions, no contactor as per instructions, no NVR as per heath and safety, no shielding (either from chips or RFI) as per instructions!

Very "Proper"! (No offend to JohnRUFC).

VFD's aren't cheap if you need a 415v output stage that a lot of motors need and are even worst when you need a 415v 2 Stage unit to run a dual speed motor (looking at £1000).
I use Cheap VFD's all the time but they necessitate a complete rewire of the machine controls. Static and Rotary converters are mostly plug and play.

 

[MattH]

 

[JohnRUFC]

No offence taken, as far as I was aware the guide would have worked. Glad to know it wasn't safe! Would love to see a more detailed guide if you ever have time?

 

[printcom]

If it helps my lathe has a 2 speed motor and that wouldn't start with a static converter, works great with a rotary one.

 

[addjunkie]

Well the compete rewire of controls scares the bejesus out of my, ive seen vfds at a 100 quid, suspect most are just wired direct to the motor bypassing any controls in the home enviroment.

Running another motor in parallel was the next option, in essence a rotary convertor, i picked up a second hand motor today for free, but hopefully wont need it.

Though might be worth while if it gets me away from the adjusting setting everytime i stop and restart the machine

 

[printcom]

Just seen this rotary converter on ebay. I might have a punt myself as i only have a 4hp one.

 

[Maker]

Well the compete rewire of controls scares the bejesus out of me.

All you do is bypass the original switches and contactors, such that the motor is wired straight into the inverter.

 

[ford34/2]

From Drivesdirect:::
The old fashioned STATIC and ROTARY phase converters are the most basic type of converters, they are not much good at all with the STATIC being large and heavy as per the right hand picture above and this STATIC type will oftern have problems running modern motors and when they do run them at all they are not at all smooth and you will have a loss of power and our customers have oftern burnt out small motors using a STATIC type converter !, Keep well clear of them !,

The ROTARY PHASE CONVERTER is a big and bulky as can be seen in the (left picture)above its an item thats makes loads of racket in the workshop and uses loads of power even before you start your machines and even then the power output is not up to the most demanding tasks, both these types of converters are so simple you can make your own if you want to with plans on how to do this being sold all the time on EBAY but I would not bother as you are sure to be unhappy with the results once you have it up and running !,

Both the STATIC and ROTARY converter have now been dropped from the DRIVES DIRECT product range so these types are basically becoming obsolete now with all discerning users opting for the latest DIGITAL PHASE CONVERTER technology but as we try to assist our customers as much as we can there are often times when a customer who already has one of the old STATIC or ROTARY converters and is unhappy with them for what ever reason wants to upgrade to the DIGITAL system and if the unit they have is in good condition we will always do our best to offer them a PART EXCHANGE deal against a DIGITAL unit,

GO DIGITAL - It's the only way to go !


http://www.drivesdirect.co.uk/
if you want to see the pictures

I have both 415V and 220V 3 phase, brilliant kit.-- All came from Dave, never had a problem with any of the four I have

Stan

 

[Maker]

I think some motor manufacturers state the warranty will be void if they are run from a static phase converter.