Oil for welding transformer tank

[Mark R]

I think I have 5 gallons of EP90 gear oil in the garage I never used in the Land Rovers which Ed can have. After all he will be doing me a favour with the Mains TX of the utility set.

I think Mike Phelan may be coming over next month if you want me to ask him the bring the gear oil and T I will Ed

cheers Mark

[AlanBeckett]

Mark,
I don't think that's exactly what Col had in mind, more like ATF
Nevertheless it's an idea, and will no doubt produce an interesting smell when it gets hot. I suspect ATF, or Hydraulic oil, is recommended because it doesn't react with rubber and plastic.
About 15 years ago my lad mixed up the drums in the garage and put EP90 in the engine of his 2A for about three months. It coped.
Alan

[Mark R]

EP90 in the engine sheesh that did need a rebuild!

cheers Mark

[Ed_Dinning]

Hi Gents, in this application the oil is mainly used to remove heat; insulation properties are secondary. I am trying to avoid any problems with a mixture of oils. plus some heat and polymerisation may set in resulting in a jelly like mass. It could even be a problem with the residue left in the internals.

I'll get it opened up this weekend and see what volume I need (and what it looks like)

Ed

[ed731pdh]

Reminds me of a few years back when they were having embarrassing transformer failures on the 25kv single phase units fitted to locomotive classes 86 and 87. The failures were traced back to nothing more than microfibres in the oil that were causing flashovers. OK, a welder is not quite in that transformer class but I would consider putting in the best you can afford as it will promote equipment longevity.

[Retired]

Hi,

As I've never oil cooled my 3 phase transformer I'm unsure what the correct oil would be. However I've just emailed Doug who invented his "Unique3phase" to ask his advise and I'm sure Doug will reply quickly; when he does I'll add the information onto the forum.

Why start at the bottom when I can go straight to the top. Doug was a great guy to deal with whilst I was building my 3 phase system and I still use it a lot to power my big Startrite 24" Volant bandsaw and home made dust extractor both running on full power at 415V.

I installed my 3 phase system for just under £120 and it still amazes visitors when I power up both machines together just as if normal 3 phase had been installed.

Do you still plan to use Doug's method as well Alan; I can highly recommend it and it is a most interesting project although could prove lethal to a novice.

Kind regards, Col.

[AlanBeckett]

Col,

I have collected a couple of big transformers for stripping. I'm not sure about the full 415, but I might go for 240 - Delta motors are readily available.

Alan

[Retired]

Hi,

Thanks Big Al, if you connect a 3 phase 415V motor from Star to Delta and use a start and run capacitor to power from 240V the motor doesn't run at full power but enough power for most duties.

About 12 years ago I did this with my big Startrite Combination 5 function woodworking machine. As this machine is fitted with three similar 3 phase 415V motors I re-connected all the motors from Star to Delta with a bit of fancy wiring so that selecting each function through the main rotary switch only a single start and single run capacitor was required. The machine is started by pushing two buttons; one is the normal run button but the other button brings the start capacitor online and once the machine runs up to speed both buttons are released; the run circuit remains online but the start capacitor drops offline; I found this to be the simplest way for me but I know other methods are available. The machine is fitted with two stop buttons for safety.

Not all 415V 3 phase motors can be connected in Delta because the old type motors have their Star connection buried deep in the windings and it's possible to destroy the motor whilst trying to dig the Star connections out. A more modern 3 phase 415V motor will usually have a "T" box (Terminal box) attached to the motor body and this houses the connections; there will be six wires from the windings and three copper straps will be seen; these straps make changing from Star to Delta very easy and also usually there is a circuit diagram stuck to the inside of the lid.

The Startrite will only "cut out" if heavy sawing is attempted as the overload trips but for general use the machine is fine and it gets a lot of use. I could phase balance it to the 3 phase 415V transformer but as it works so well why bother. The biggest problem with this conversion is in trying to obtain the correct capacitor ratings. The start capacitor can be oversize as it is in circuit for only seconds but when I first started doing such a conversion I've had a run capacitor explode which is an attention grabber.

Back on topic and I'm pleased to add the reply about the oil from Doug at "Unique3phase". I knew Doug would respond quickly and I've just thanked him; here is the reply in full and I am unable to expand on the information because I have no knowledge of oil cooling a transformer;


Hi Colin, Thanks for all the plugs you put in for me. I think it helps boost sales as everyonce in a while there are a bunch of people that buy and then it slacks off for a while.

"I used the Dextron transmission fluid because I found some one on the web that was an amateur radio operator that had investigated it for use in a oil cooled dummy load. He stated that the fluid was recommended for use in the hydraulic units on line service trucks. As in power line high voltage repair. I don't know if that was a marketing ploy by the makers of Dextron or not but it has a high flash point. I found it in 5 gallon pails at a tractor supply store so it was a lot cheaper then buying it in quarts or liters. Doug"

I hope this is of use Ed but at least it is something to think about and will possibly save you a lot of money.

Kind regards, Col.

[AlanBeckett]

Hi,

Thanks Big Al, if you connect a 3 phase 415V motor from Star to Delta and use a start and run capacitor to power from 240V the motor doesn't run at full power but enough power for most duties.

Indeed. That's what I've done on my Chipmaster.

About 12 years ago I did this with my big Startrite Combination 5 function woodworking machine. As this machine is fitted with three similar 3 phase 415V motors I re-connected all the motors from Star to Delta with a bit of fancy wiring so that selecting each function through the main rotary switch only a single start and single run capacitor was required. The machine is started by pushing two buttons; one is the normal run button but the other button brings the start capacitor online and once the machine runs up to speed both buttons are released; the run circuit remains online but the start capacitor drops offline; I found this to be the simplest way for me but I know other methods are available. The machine is fitted with two stop buttons for safety.

I built a gadget to do it automatically.

Not all 415V 3 phase motors can be connected in Delta because the old type motors have their Star connection buried deep in the windings and it's possible to destroy the motor whilst trying to dig the Star connections out. A more modern 3 phase 415V motor will usually have a "T" box (Terminal box) attached to the motor body and this houses the connections; there will be six wires from the windings and three copper straps will be seen; these straps make changing from Star to Delta very easy and also usually there is a circuit diagram stuck to the inside of the lid.

I've come across a few of those. It is sometimes possible to dig the connection out but as you say it's not always possible and sometimes writes off the motor.

The Startrite will only "cut out" if heavy sawing is attempted as the overload trips but for general use the machine is fine and it gets a lot of use. I could phase balance it to the 3 phase 415V transformer but as it works so well why bother. The biggest problem with this conversion is in trying to obtain the correct capacitor ratings. The start capacitor can be oversize as it is in circuit for only seconds but when I first started doing such a conversion I've had a run capacitor explode which is an attention grabber.

You've nearly convinced me to buy the CDs

Back on topic and I'm pleased to add the reply about the oil from Doug at "Unique3phase". I knew Doug would respond quickly and I've just thanked him; here is the reply in full and I am unable to expand on the information because I have no knowledge of oil cooling a transformer;


Hi Colin, Thanks for all the plugs you put in for me. I think it helps boost sales as everyonce in a while there are a bunch of people that buy and then it slacks off for a while.

"I used the Dextron transmission fluid because I found some one on the web that was an amateur radio operator that had investigated it for use in a oil cooled dummy load. He stated that the fluid was recommended for use in the hydraulic units on line service trucks. As in power line high voltage repair. I don't know if that was a marketing ploy by the makers of Dextron or not but it has a high flash point. I found it in 5 gallon pails at a tractor supply store so it was a lot cheaper then buying it in quarts or liters. Doug"

I hope this is of use Ed but at least it is something to think about and will possibly save you a lot of money.

That sounds eminently reasonable.
Bear in mind that American Gallons are smaller than ours, about the only thing that is

Alan

[Retired]

Hi,

Thanks Big Al, I thought it worthwhile adding the notes because not everyone knows 3 phase motors can be run from domestic 240V supply.

Out of curiosity I've just had a look on eBay to see if Dextron oil is available so here's a link Ed that might be useful.

http://www.ebay.co.uk/itm/ATF-DIII-DEXRO...e_Cleaning&hash=item56368c52e4#ht_1804wt_754

Kind regards, Col.