Liquid Resistance Soft Starter

Looks like a form of Statormatic. Statormatics use a caustic solution.

Have a look for a company called AOIP, they are based in France but like most companies they have a wide network.

Yes, I've seen this kind of thing only once before about 20 years ago on a slip ring motor, that's called a Vapormatic starter, but I was told the same concept on a squirrel cage motor is called Statormatic and I investigated it.

The working concept is the varying resistance of an electrolyte as it heats up. So instead or relying on electrodes moving up or down in an electrolyte as a more traditional liquid resistance starter does, these are fixed but the electrolyte heats up or boils as current flows, which lowers the resistance. In the slip ring version the liquid resistance is used to change the rotor circuit resistance, which alters the torque as it accelerates. But typically it's used just as a soft starting method for slip ring motor because its difficult to maintain a specifit electrolyte temperature for something like varying speed or torque, which is what the liquid immersion types can do.

In the squirrel cage version, it's just like a reduced voltage primary resistor starter but the resistance is variable, lowering as the motor accelerates, giving more voltage to the stator as it does. Then once at speed, the bypass contactor closes. It would provide a softer start than a primary resistor starter would though because of the varying resistance.

All in all though, all of these technologies were used when there were few alternatives. Electronic soft starters are a quantum leap better, safer and less expensive now. I'd hazard a guess that you will be able to buy a complete new solid state starter unit for what it will end up costing to repair this one.

Vapourmatic and Statormatic are made by the same company. Both work very well if maintained correctly.

The big difference is the Vapourmatic has multiple three pole electrodes in the same tank where the Statormatic has three separate tanks.

The biggest failure is due to not maintaining the electrolyte level. The bottom of the electrodes burn and starting becomes erratic. The bigger units have low electrolyte level built in to them that prevents starting.

I'm just advising on renovating two much neglected Vapourmatics. The spares are salvaged from units I installed as an apprentice. Spares are still available, why buy new when you can get serviceable parts within the company.

New spares are going to be ordered to keep as company stores stock.

It's been a weird involvement with this renovation, three companies involved. Two of the companies I worked for in the past, the other company was a rival but they knew me.

I'm retired so really it doesn't involve me, but life being what it is I got involved. I'll be lucky to get a couple of bottles of malt out of it.

But what the hell, it's been fun helping out, and I haven't had to shift off my backside or get my hands dirty!