Help with phase converter. Old Bradbury screw lift & very old converter.

[Jelly_Sheffield]

it all sounds very simple by the experienced memembers but I think it's a black art.....
I'm in the same boat as u and am really considering VFD for my 3 phase gear....

If you're finding the issues with phase convertors confusing (and it is confusing, especially because there's lots of special cases, and lots of conflicting advice based on people's anecdotal experience online)...

If you go VFD, I would recommend buying from someone like MotorsAndInverters.co.uk or Invertec, where you can ring or email, tell them your use case and motor details and they will help specify what you need, pre-programme all the parameters, give you tech support installing it and offer a decent warranty.

The cheap fair eastern VFD's can be a real bargain, but are often a nightmare to set up until you're familiar with that specific model...

And the documentation is always pants, I recall my mate Tom, who is an electrical engineer, desperately struggling to interpret a chinglish instruction manual for a VFD he was fitting with a new motor on his Myford and eventually him messaging a colleague of his who speaks fluent mandarin asking them to read the chinese version of the instructions manual...

After about ten minutes came the sage response:

"F' me mate, the Chinese version is if anything less well written, you're just going to have to guess."

so a bought unit from Transwave /plug n play seemed good until reading the above....so again, now undecided...and I cant afford to pay £1500 for something that may not do the job.

If you're concerned, it's worth ringing them and asking for advice.

They're a proper old-school manufacturer, it's proudly designed and hand assembled in Birmingham and they back it up with technical support from actual engineers who understand the kit.

Based on previous experiences with them, if you rang up and in the conversation they determined you'd recently bought something not quite right for you from them...

I strongly suspect they would offer to take it back and give you full credit on the right machine for your needs, or if it's second hand to modify it (if possible) at a very reasonable rate.

 

[Onoff]

Where can I get myself a 230v transformer for this type of controls, see picture.

Erm...doesn't quite work like that. In fact quite likely you could retain that changeover switch for a single phase set up.

Open the box up and show us inside if you can.

 

[Onoff]

See specifically my post #43 here:

Manual / Hand pump conversion of 3ph car lift

The output from the VFD should be connected directly to the three brown wires coming from the motor. There should be nothing in between VFD and motor, only copper and plastic. In the photos, it looks like the motor wires go into the blue box. Disconnect them there and wire into the VFD. That...

www.mig-welding.co.uk

 

[minimutly]

No motor overload from what I can see! I think I it’s the current too it as once it starts to struggle that’s when it trips, obviously as the power drops the current increases causing the trip!
I’m leaning towards the single phase motor swap due to the limited amount of support with the VFD’s and their parameters.

The lift is constant current once it starts, unless the thread sides are deformed over a portion of travel - once off the ground it should go to the top...

 

[Tom_79]

Erm...doesn't quite work like that. In fact quite likely you could retain that changeover switch for a single phase set up.

Open the box up and show us inside if you can.

It does look like from the data inside those controls that it can be used single phase.

 

[Onoff]

Usually, to make a single phase motor go one way or the other, you swap the links in the terminal box. So clockwise on the left, anticlockwise on the right:

https://flic.kr/p/2f3heYT

I put the brass strips to one side. Then took a 4 core cable to the motor:

https://flic.kr/p/2f3hgqR

The change in direction is by operating one of two contactors taking the place of swapping the brass strips in the terminal box.

This is on the Bradbury. Literally 2 push buttons at 230V potential.

https://flic.kr/p/2f3hgTK

On the Grazia two push buttons operating at 24V potential.

I'll get pics, more details in a day or so.

 

[Relic]

Is there anything between the motor and the converter? Switch, overloads etc? Strange that it stops mid travel.
The two post screw lifts are a pig to get to start, my old Tecalmit (if I recall) will not start on a full load lift, the belts smoke, it's on a single to 3 phaseconverter.

 

[Relic]

Yup.
Needs an idler motor for 3rd phase.
Converters usually give a bit of voltage spread over 3 phases.
Not exactly even but work.
Idler motor runs full time.
2 phases of motor across 400 transformer output.
L1 and L3
L2 is off off motor directly..
Suspect your lift motor should be delta connection with a idler motor providing the 3rd phase.
Use a clip on type of ampmeter to see what's happening.
Symptoms you describe are classic under voltage 3 phase motor operation.
By that, a phase missing.
With operation on only 2 phases, you should be able to hear motor growling.
By testing current is flowing on all 3 phases should narrow problem.
Supprised it even gets away.
Common to find output shaft cut off on idler motor.
Your transformer is tiny.
Any KVA rating visable on transformer?
Usually have to select a D curve circuit breaker to hold in on start up.
Moulded electronics could be part of SCR soft start for an idler

 

[Tom_79]

Yup.
Needs an idler motor for 3rd phase.
Converters usually give a bit of voltage spread over 3 phases.
Not exactly even but work.
Idler motor runs full time.
2 phases of motor across 400 transformer output.
L1 and L3
L2 is off off motor directly..
Suspect your lift motor should be delta connection with a idler motor providing the 3rd phase.
Use a clip on type of ampmeter to see what's happening.
Symptoms you describe are classic under voltage 3 phase motor operation.
By that, a phase missing.
With operation on only 2 phases, you should be able to hear motor growling.
By testing current is flowing on all 3 phases should narrow problem.
Supprised it even gets away.
Common to find output shaft cut off on idler motor.
Your transformer is tiny.
Any KVA rating visable on transformer?
Usually have to select a D curve circuit breaker to hold in on start up.
Moulded electronics could be part of SCR soft start for an idler

So I either need to add an idler motor, change to single phase or VFD. I don’t fancy VFD for the lack of info and setting them up! I don’t like trial and error haha. Time is off the essence now. Work is stacking up and no lift.

I’m a little bit simple in terms of idler motor. How does it wire up with my current set up? Like what wires to where?
My friend has a 3kw 3 phase motor just sat there and was thinking about trying it.
With what I’ve read I’m surprised it even runs agreed.
I have been drawn towards the single phase swap because of simplicity.

 

[Tom_79]

Usually, to make a single phase motor go one way or the other, you swap the links in the terminal box. So clockwise on the left, anticlockwise on the right:

https://flic.kr/p/2f3heYT

I put the brass strips to one side. Then took a 4 core cable to the motor:

https://flic.kr/p/2f3hgqR

The change in direction is by operating one of two contactors taking the place of swapping the brass strips in the terminal box.

This is on the Bradbury. Literally 2 push buttons at 230V potential.

https://flic.kr/p/2f3hgTK

On the Grazia two push buttons operating at 24V potential.

I'll get pics, more details in a day or so.

Okay thank you! It would be good if could use those controls still, it does look like I would be able to!

 

[Erie Fred]

So I either need to add an idler motor, change to single phase or VFD. I don’t fancy VFD for the lack of info and setting them up! I don’t like trial and error haha. Time is off the essence now. Work is stacking up and no lift.

I’m a little bit simple in terms of idler motor. How does it wire up with my current set up? Like what wires to where?
My friend has a 3kw 3 phase motor just sat there and was thinking about trying it.
With what I’ve read I’m surprised it even runs agreed.
I have been drawn towards the single phase swap because of simplicity.

The idler is parallel to the lift motor, upstream of the lift's controls, so it runs all the time.

 

[Erie Fred]

Okay thank you! It would be good if could use those controls still, it does look like I would be able to!

On most single phase motors I am familiar with, you bring out the starting winding leads to a DPDT
switch.
99% of single phase motors will not plug reverse, so be forewarned.

 

[Relic]

A word of caution.
Did an exercise last year with going from 3 to single phase on a car lift.
Did a temporary 2.2kw single phase as a trial.
Got car half way up as it ran out of grunt.
Bigger single phase motors have draw backs.
Dear to purchase, hard to find in stock and inrush issues at startup
Drives have advantages but at cost.
Do not recommend DIY drive installs without tech support from someone.
Hard enough to remember to read a 3 phase motor name plate.
Depending on brand, somewhere between 3 and 5kw the connection of links requirements change.
You could Google connecting a booster converter for research.
Commercial brands info out there you could adapt from.

 

[Onoff]

Did an exercise last year with going from 3 to single phase on a car lift.
Did a temporary 2.2kw single phase as a trial.
Got car half way up as it ran out of grunt.

BiL found the same until he geared it down. Not a commercial thing where speed is important. It lifts my Mondeo estate to full height without missing a beat. If it lifts / lowers at half the intended speed it's not the end of the world. Not sure on the kW rating of the new single phase motor. I've yet to check for the OP along with the sprocket and chain details/ratio.

 

[addjunkie]

So I either need to add an idler motor, change to single phase or VFD. I don’t fancy VFD for the lack of info and setting them up! I don’t like trial and error haha. Time is off the essence now. Work is stacking up and no lift.

I’m a little bit simple in terms of idler motor. How does it wire up with my current set up? Like what wires to where?
My friend has a 3kw 3 phase motor just sat there and was thinking about trying it.
With what I’ve read I’m surprised it even runs agreed.
I have been drawn towards the single phase swap because of simplicity.

Talk to one of the specialist outfits who deal with such things, they will tell you how…..and if itll work.

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[Geoffm]

I would look at a 230v in, 400v out VFD unless your motor can be changed to 230v 3ph, as the 230 in/out vfds are cheaper and easier to get. You can set the startup ramp time to overcome the startup force an limit current requirements.

 

[Brad93]

VFD's are a piece of ****, not sure what would require a professional, specialist or tech support.

 

[minimutly]

VFD's are a piece of ****, not sure what would require a professional, specialist or tech support.

Sorry @Brad93 , but the world runs on VFDs, or VSDs to give them their other name. The bigger ones tend to be 3ph in 3ph out though. Starting out with 240 is not good, nor is running a motor at 230v 3ph, but mostly it gets the job done.
You can get voltage doubling VSDs that put out 400v 3ph, but they are not cheap, and sometimes get you into trouble - my Fritz Werner mill was blowing output and driver stages one after the other, I kept fixing it until I ran out of spares, but in the end found out the real culprit - the forward reverse switch buried in the machine had got damp and was tracking across. I hate to think how much in time and money that mistake cost me...

 

[Onoff]

Went and had a look at the BiL's 2-post Grazia that as aforementioned is converted to single phase.

A 1.5kW TEC motor from Ebay etc:

https://flic.kr/p/2q7apUm

1/2" chain & sprockets. 18T for the small one, 36T for the big one.

https://flic.kr/p/2q79aJh

https://flic.kr/p/2q7apSN

https://flic.kr/p/2q7bjnz

https://flic.kr/p/2q7bjoS

 

[Brad93]

Sorry @Brad93 , but the world runs on VFDs, or VSDs to give them their other name. The bigger ones tend to be 3ph in 3ph out though. Starting out with 240 is not good, nor is running a motor at 230v 3ph, but mostly it gets the job done.
You can get voltage doubling VSDs that put out 400v 3ph, but they are not cheap, and sometimes get you into trouble - my Fritz Werner mill was blowing output and driver stages one after the other, I kept fixing it until I ran out of spares, but in the end found out the real culprit - the forward reverse switch buried in the machine had got damp and was tracking across. I hate to think how much in time and money that mistake cost me...

I wrote "Piece of P *I S S" but it blurred it out.
I'd use a VFD