Thread: One "FAWOOMP" was all it took

I know that feeling - I had my mill stop on Saturday. I think a phase dropped out momentarily (lights flickered) but it was enough for the thermal overload on the mill to trip. Kept pushing the start button and nothing would happen. It took me a couple of hours to finally twig what the problem was and how to fix it. I was sweating in the mean time...

If it helps I could make up a tee nut for you but if you haven't got three phase to drive the lathe it probably won't advance the cause much. Main thing is to work out what caused the problem in the first place so you can prevent it happening again.

Michael

Thanks for the offer Michael; but as you say; not much use with no 3 phase. Will have the Hardinge disconnected tomorrow and move it so I can get the hoist into place to lift the rpc down. I will then take it back to the manufacturers in Melb. I think that there is a design fault with the case not having enough ventilation for hot climates. Will see what the cost of repairs are first.
How many VFD's do I get for $4G. I only need about 17.

Ken

The phase converter is $4000? That would be a lot of VFDs

Originally Posted by Toggy

Thanks for the offer Michael; but as you say; not much use with no 3 phase. Will have the Hardinge disconnected tomorrow and move it so I can get the hoist into place to lift the rpc down. I will then take it back to the manufacturers in Melb. I think that there is a design fault with the case not having enough ventilation for hot climates. Will see what the cost of repairs are first.
How many VFD's do I get for $4G. I only need about 17.

Ken

Sorry to hear about your RPC. 17 VFD's? Wow that would be a massive PITA to change over! Simon

Outch... At least you got a FAWOOMP, All I usually get is a BZZT SPLAT...

When you get it down, take some pictures and see what went bang. They are pretty simple things generally speaking, you might just need a new idler motor. I assume it's got the digital controller with banked capacitors for load correction? If that's fried, you could probably still bypass that stuff and run it without the correction..

Let me know when it's down.

Ray

I think we have the Huanyang ones down pat. You should be able to get 17 of them (3kW each) for about $2700... add $150 for each 4kW one you need or deduct $50 for each smaller one.....

What to do? I also have a supply problem which is marginal. It is 2 phase to the sub-board, but one phase then to each shed. Anything over 3hp is a struggle to start; though the 5hp idler in the RPC 'used'' to start ok. 240v 3ph will be twice the amperage of 3 ph per line so may be a problem with multiple motor machines. This is the reason I went RPC originally, and the fact with 3ph it apparently helps smooth out the line balance. Start with the biggest motor then down to the smallest.
A cheap 3 ph generator may be the go.
Another thing with vfd''s is converting each of those motors to delta? plus I no longer have a pet sparkie for all the wiring changes. Also the T&CG has the integrated balanced motor in the head.

Ray,

Climbed up the ladder already and peeked inside. No burn, leakage or smoke marks to be seen. Idler motor clatters like crazy which I believe is a sign of losing a phase. Obviously the 240v leg is still ok.

Ken

A cheap 3 ph generator may be the go.

yes have started exploring that option myself. To get 3 ph mains on to shop here = big $

Had a visit from Ray & Josh this afternoon.

The idler motor and autotransformer seem ok. The control panel was a different matter though when cover came off. Scorch marks and tracks as well as quite a few of the circuits just plain missing. Vaporised, turned to plasma and and fused to nearby metal parts.
Cost of replacement circuit boards - $880. ouch. Hopefully the new board doesn't go the same way.

Ken

Originally Posted by Toggy

Had a visit from Ray & Josh this afternoon.

The idler motor and autotransformer seem ok. The control panel was a different matter though when cover came off. Scorch marks and tracks as well as quite a few of the circuits just plain missing. Vaporised, turned to plasma and and fused to nearby metal parts.
Cost of replacement circuit boards - $880. ouch. Hopefully the new board doesn't go the same way.

Ken

The control system consists of two boards, one power board with high current fets mounted underneath on a simple flat aluminium sheet as a heatsink, the top board has the logic and custom processor to control the fets, which are arranged to switch capacitors in or out of circuit. depending on load. The board might be repairable in a pinch, but the tracks that vapourized, left a copper film over parts of the logic board, that would be very difficult to repair. A replacement board is the only real choice.

Generally it's a nicely made rotary phase converter. It needs better cooling for the fets, and maybe moving the idler motor out of the enclosure would help with heat.

Ray

Originally Posted by RayG

The control system consists of two boards, one power board with high current fets mounted underneath on a simple flat aluminium sheet as a heatsink, the top board has the logic and custom processor to control the fets, which are arranged to switch capacitors in or out of circuit. depending on load. The board might be repairable in a pinch, but the tracks that vapourized, left a copper film over parts of the logic board, that would be very difficult to repair. A replacement board is the only real choice.

Generally it's a nicely made rotary phase converter. It needs better cooling for the fets, and maybe moving the idler motor out of the enclosure would help with heat.

Ray

I fully admit that I don't have experience with these setups, but it would seem to me that if the cooling is a weak point, then adding a couple of cooling fans from say a computer enclosure would be a good addition at this point.

How long did this thing last before it cacked itself? I've been considering buying one... maybe...

Saw something last night with 2009; but I am sure it was prior to that. They are supposed to last for 30 odd years. I have been pleased with it up til now. An interesting thing noticed by RayG was that the controller circuit boards are made in China. Funny how a company claiming to be all Australian is using chinese sourced parts. Motor & transformer appear to be Asian imports. The current controller boxes are supposedly now made in Aus, I may not be the 1st to have had meltdowns on possibly sub standard asian sourced electrics. I will certainly ask the hard questions tomorrow when I pick up the new controller from the factory tomorrow. To be fair to the company, they have been good to deal with previously.

We have already discussed cutting a hole in the rear of the case and fitting a fan. Also I would like to make a new stand and fit the idler motor externally like the larger models. It produces lots of heat and there is minimal case ventilation. May work in cooler climes, but I don't think they have allowed for constant over 40c temps.

Ken

Hi
After building my perfect workshop and putting in 3 phase the wife decided we neede a bigger house for the 3 kids.

New place has the worst switchboard I have ever seen and has 250mm flowing in the earth!

I am saving up to have switch board redone and problems solved but 3 phase is not really an option.

I bought one of these Phase Changers at about 3-4Kw to run the mill, grinder, shaper etc. fantastic, quiet, heavy!!
I had to change the control connection in the mill so the contactors worked but then it has the advantage of being able to run multiple motors simultaneously up to its full load.
Bought it on gumtree for a fraction of new cost and been very happy with it. It will not run my big welders, but I bought a new switchmode single phase welder and it will out perform the hundreds of kilos of the old ones and I can carry it.

James
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