3 phase - again - DSG

I would like to buy a larger lathe, one with a 7.5 HP motor. I only have single phase supply in a rural area. Last quote from Npower for 3 phase involved paying for a new transformer on a pole (£11,000). I already have a few lower rated machines on various solutions (lathe with rotary converter) mill with VFD. I am aware that the 7.5 HP motor is unlikely to be dual voltage. I am getting conflicting advice from suppliers (depending on what they sell). I am hoping the new lathe may be a DSG. I have seen 10HP VFDs on the ebay for £250 which seems very cheap. Wondered if anyone would have any strong feelings or experience at this sort of power ?.

Hi,

I have a DSG 17" x 72" lathe with a 7.5hp motor which has successfully run on a home made single to three phase rotary convertor for over 12 years now and never been any trouble with anything I've tackled.. The motor on mine is a Crompton single voltage.

Had thought of going VFD but its works so well not going to bother, great lathe, one of the best things I've bought!

Before doing any thing lift the lid on the motor terminal box and you may find 6 terminals, that being so, its easy to reconnect into to delta. Alternatively its not all that difficult to take the motor apart and locate the internal Star point. A rewind shop will do it for you. If you choose to do it yourself, then once apart look out for a lump in the windings (either end of the stator) carefully examine the windings and you should see 3 windings coming together. With a sharp knife cut away the insulation, solder or mechanically crimp three wires to original ends re insulate and bring them out to the terminal box. If you get as far as that and unsure of how to reconnect into delta give us another call,again very easy.Ted

I am doing the same as stated in the opening post. I have a 7.5 HP Colchester and I am putting a VFD in the electron stream to run it. It's Asian and will post the outcome when done. My electric experience is about average and I hope no sparks result, so here goes.

7.5 hp is just getting to the point where a star delta starter could be used in which case the delta connection may be for 415v and the star for 690v. Check the rating plate, just because you have a 6 teminal connection does not mean the delta voltage is 230v.

Mike

rating plate says 400/440.

I can put you in touch with a company that's selling a 1ph 240V to 3ph 15KW or 20Kw with filter, wanted £2k.

15KW might just be man enough not familiar with the DSG's is it clutch or spindle start on them. It will also run the other machines no need to unplug.

Do have the 7.5KW version the only way that would power is to go direct to motor.

7.5 hp! what are you expecting to do with it?

Steve

Anything he wants I would imagine.

graham.

7.5 hp - that's on a par with the rated power of my first road car - '34 Austin Ruby! It would just about pull the skin off a rice pudding, given a following wind. I'll wager that lathe will do a darned sight more than that - but you won't be able to get three mates on it down to the pub!

John

My 17" x 72" DSG lathe has a resistor delay unit to give soft start. It draws around 8a idling (4.5 hp) and the current goes up as a cut is applied. Just checked and on a cold lathe its pulling around 18a on top speed which is around 10 hp before any cut goes on. I notice on a lot of the larger DSG lathes an ammeter is standard. Great lathe!

Do not need all the horsepower, but whenever it gets finished I will love the rigidity.