Help Requested - 3 Phase Rotary Switch Wiring

Not sure what you need the wiring of the motor for.

If you take the old switch apart and look at its internal wiring then you just connect the wires at the new the same way it was.

Make sure you know the wiring of the new switch.

Square D makes quite a few rotary switches. Nice of you to give use a chance to guess which one.

If it is a drum switch like the one here on my Bridgeport mill. Then all it does is swap phasing between two leads. Three phase input is terminated on one side of the switches input terminals. Jumpers are ran to the other side of input terminals. Two of the jumpers are swapped.

Speed is changed with another switch.

Used these on some hanger doors back 30 years or so.

I tried to attach photos but can't seem to figure it out. The switch in question is a K4Y

P1055D.... good up to 7.5 hp at 220v. The motor is an AEG delta y motor....1.1/1.4kw

Motor leads at the terminal board on the motor are 1U 1V 1W on one side....and

2U 2V 2W on the other.

I rewired a saw in the workshop which had similar windings a few months ago. Will try to dig out wiring diagram tomorrow, if no-one's already posted it.

Does a reversing saw uncut your wood, so that you can try again?

Minute I hit "Submit ... " I knew some smart-a$$ was going to come up with something like that . 'Course the fekkin' saw didn't reverse, but it did change speed. Other side of switch would just be same pattern with 2 phases swapped.

Then again, with some of the incompetent gits in our workshop, maybe reversing it would be a good idea - could stick their fingers back on. Maybe I should re-rewire it to reverse.

I guess/hope you meant that as funny, though I am not sure myself. It was not clear....

I nearly always add a smiley to show my "direction" when I am being sarcastic.... Get it?

Changing direction of a 3 phase motor is the simplest thing to do, the method has already been posted in this blog, but for those who missed it, you only need to swap any 2 of the three phases with each other. It does not matter which. Obviously following electrical safety procedures.....

Many pumps with 3 phase motors turn in the wrong direction every day all day in some bad installations, often with obvious problems that nobody seems to understand, nor fix, sadly.....its important....but often completely missed at install time....

Some pumps will pump far less, some will run hot, it depends mainly on the pump design. Some won't work at all which is really good and informative....

Furthermore, a 3 phase saw may actually turn in the wrong direction when first connected and knowing the above means that the rotational direction can be easily, simply and correctly changed..!!

Just so's you knows and understands.....

PS. I am being funny/sarcastic Tornado, in case you did not get it.....

Have a great day!!

That would make a good Christmas gift

Sounds like you may have a multi voltage motor. If you can't get the info from the manufacturer, any good motor repair shop should be able to check it out an tell you.

Hers is a link to your switch:

http://www.ebay.com/itm/Rotary-Switch-Square-D-Type-K4Y-P1055D-5-position-/110334665012

Connections are as I described above.Any questions, feel free to ask.

Does the switch change speed as well as direction?

Yes, the drum switch is the cylindrical panel mount type and has 5 positions, clockwise from 8 o'clock position, Low speed 2, Low speed 1, Off, High speed 1, High speed 2.

That doesn't sound right - wouldn't it be forward hi, forward lo, off, reverse lo, reverse hi? Or vice versa. You wouldn't want to go from forward to reverse without going through off. Here's a link to an ABB 2-speed motor. You should be able to use a volt-ohm meter to see if yours is like this. With a meter and investigating the innards of the old switch as others have suggested, you should be able to figure it out.

Why is a 2-speed motor needed on a lathe? These things have gears and belts and all sorts of clever stuff to change the speed - just ask Del.

What suggests that the motor to hand is 2-speed? How did the call with the motor manufacturer go?

I was on this problem a year ago, at that time I called AEG Europe, they handed me off to AEG Canada, who then told me that my problem was indeed my problem.

The lathe by design is a two speed. Rated HP is available in high speed only, with the low speeds being used for delicate operations such as fine threading where torque is not so much of an issue. This machine combines gearing with motor speeds to offer a broader range of gearings.

Is it an original motor or a replacement?

What did the lathe manufacturer say about the motor and its wiring during the call to its Technical Helpline?

A year to sort this? Sheesh.

How many contacts do you need to change direction? Does your rotary switch meet those requirements.To determine the wiring of the motor and using a rotary switch to change direction should be a simple task for an electrician but if you are going to have two speeds as well it is going to be a bit more complex.Does your rotary switch have 5 positions?

Yep, 5 positions....it is a colossal task trying to wrap my head around all that needs to happen. The switch has 30 terminals and a bunch of jumpers to use.

What is the original motor HP? You say it is a "small lathe" I would guess that the motor is about 5 HP. If the machine itself is in good condition, you might consider replacing the motor with a modern inverter duty 3 phase motor and using a variable speed drive. The cost would be about $1000 ( check out Automation Direct), but having the variable speed drive would make it a great machine tool.

The motor is a 1.1/1.4 kw.... I guess a half horse or third horse

More like 1.5 - 2 hp

This suggestion, in my opinion, has some serious merit and I will consider it especially. Although there is a ton of helpful information here, this suggestion makes separate motor speeds and analog controls a thing of the past. Then the reversing of the VSD might be more easily accomplished. Although the Emco Maximat 11 is a beautiful lathe, with excellent craftsmanship, the electrics can be seen as outdated and this suggestion opened my eyes to the prospect of using this breakdown as an opportunity to upgrade.

I'm limited in knowledge, I have no surviving original switch....as I mentioned. I have worked with three phase...and reversing, but wiring for speeds at the same time makes a very intricate drum switch necessary. Furthermore, the diagram does not show switch positions for different speeds, only the powered off layout of the components.

I just checked Automation Direct catalog (www.automationdirect.com) and they list a 2 HP 3 phase 230 VAC inverter duty motor for $441 and a 230 Vac 3 phase 2 HP drive for $250..

I have no commercial interest in Automation Direct, but I have used them regularly for industrial automation equipment and have had great success with their products

I will call them. The switch to VFD could make the machine really flexible.

It's too late at night now. I have wired two speed machine tools before where they use Dahlander two speed motors. Will sort it tomorrow afternoon.

Over at Practical Machinist, there has been similar discussion. One post leads to this(see fig. 7) which might be of some use. Does your motor nameplate have a connection diagram? That would help.

The motor has no such connection diagram, for reasons I cannot fathom, especially given the complexity of the problems if you don't have one.....

Over my head, but you may have/need Dahlander Connection, explained here.

Yes, Yes, Yes.......Thank you...my data plate indicates delta star star.....also the

1U 1V 1W 2U 2V 2W match......my continuity checks also agree. The diagram is useful to me. Thank You.

Probably there is another switch which takes care of the speed selection, and for the forward reverse selection, any rotary switch that can interchange any two poles can do the job.First you have to assertain weather the original selector switch, was just a forward/ reverse switch or did it had a speed selector as well.

Believe it or not, there is an off on switch prior to the drum switch....and the drum switch functions to both reverse and change speeds.

Normally, on a lathe, the reversing of rotation is done mechanically via a lever and not by switching.

Maybe your rotary switch is used only for speed change.

I have a 14 X 40 Enco lathe which changes the rotation via a lever on the apron.....the attached shaft drives a small cam operating a micro switch only. It too is a two speed motor, by the way....and may also be Dahlander type.

The site tells how to post jpeg's but I have no idea how to perform what it is trying to say. I have photos at the ready.

The lathe has an off on switch on the front, then a 5 position speed and direction control knob, with the colossal drum switch behind it. I would know to kill the power before reversing or changing speeds. I don't know if the machine was designed fail safe in this manner.

Now the drum switch I bought is for separate windings for the speed change. It appears that Dahlander is more complex due to having to break 3 phases at the same time to perform the speed change. So the drum switch may need more terminals in order to perform the Dahlander type circuit. The K4Y I have has 30 terminals. Awesome input, Thank you.

Dahlander circuit- Reversing two speed