help with motor wiring

[Trivo]

I have now got my lathe and it is wired for 3 phase and I only have single phase 240V but reading the instructions supplied most seem to be 220v single phase. question is do they use the same motor with diffrent conections or a different motor? if the same motor what wires? the diagram shows 4 wires conected I guess 4 wires so they can get reverse any ideas

Thanks Trivo

[loobosh]

hi

do you have the cover for the wire box if so look inside it should be there.

the wires have # or letter stickers it should tell you how to hook it up.

                                              loobosh

[mvr]

The 240 vs. 220 volt difference is not significant.  Basically these are different ways of designating the same nominal voltage (note that they are within ten percent of one another).  But the three phase vs single phase difference is important. Essentially three phase is looking for a voltage source that is shifted less than 180 degrees from the others.

  You can buy/build a phase converter to run a three phase motor under standard single phase power.  A google search will yield lots of plans.  Static converters use capacitors to shift the phase and make a third leg of power, but they have trouble starting motors under load.  Dynamic converters use an idler motor to inductively create the third leg.  Both systems will cost some money.

best,

Mark

[Trivo]

Loobosh

thanks found the cover and it has the conections only prob is that in the instructions it has 4 wires and this only has three?

trivo

[Flux]

On the 220v connection 4-5-6 is the star point, you dont need to connect it. Just use 3 leads to 1-7   2-8    3-9

Flux

[loobosh]

the motor is wired for 440 volts you have to take all the wires that are taped apart

and reconect them for 220.

to do this connect 4-5-6 together then 7-1 add a red wire to those

8-2 together add red wire then 9-3 then red wire to them

                                                loobosh

[ghurd]

It is still a 3 phase motor, and you only have single phase available.

It may be best to get another motor.

G-

[alcul8r]

The motor is 3-phase.  It can not be run off single phase without a converter.

If you have a 3/4 hp 3-phase working motor laying around I can tell you how to hook it up as a phase converter.  Your best solution, if this is the only three-phase appliance you have, is to replace it with a single phase motor.

Rex

[Ungrounded Lightning Rod]

Dynamic converters use an idler motor to inductively create the third leg.  Both systems will cost some money.

But if you've got a spare three-phase motor - HP rating as big as the one in the lathe or somewhat larger - lying around it takes very little money.

Mount it solidly to something.  Hook up power to it (through a motor contactor or suitable switch for motor loads) on two of its legs, a big RUN capacator (or several in parallel) between one of those and the third leg.  (They're mostly acting as start capacitors but run capacitors are rated for continuous duty so you don't have to unhook them once the motor is running - and they DO help during run, too.)  Hook the three wires from the motor also to the input lines on your lathe.

Turn on the motor's switch with the lathe off, wait until it's up to full speed, and turn on the lathe.  You can switch off both at once or lathe first.

Nothing to it.

(Hanging capacitors across the lathe motor in the same way and leaving out the idler motor will get it to start and run.  But you'll have to reduce your cutting rates to about a third of normal to keep the motor from overheating unless you use a LOT of capacitors.)

[Walt]

Trivo

One other thing that you need to consider.

Depending on the complexity of the electrical controls of the of the lathe, if you use single phase, you may have to replace the transformers and some of the switches.I ran into this problem while hooking up a friends lathe, it was an old Monarch lath. Just keep this in mind.

Keep after it, you will get there.