Electrical questions

Ok...got the Larios Horizontal mill all painted and now its time to do the electrical..and am running into a snag...
The mill has 2 motors..a 2 speed/6 wire motor for the spindle and a stock 3 wire for the table feeds
Of course..all are 240 volt, 3ph
Ive got a bunch of drum switches and various relays and as I was sitting down to do a wiring diagram..I realized...that the spindle motor was going to need a form C relay or switch. Dont have one. Shit..well..I have one..but its a 100 amp..and is about the size of a poodle. Well..sniff..I cant stick that in a cabinet, now can I?
I think..think..the spindle is 2hp, the knee motor is probably 1/2hp
The issues.....I need to bring in 3 wires AND reverse two of them for the knee...standard reversing switch/contactor should work for that. It would be nice if I could shut power to the knee off totally..but cant with a standard reversing contactor..damnit. I can with a drum switch.
Poop.
The biggie is the spindle motor. Anyone got a form "C" ..normally open/normaly closed, 3 ph, 2-3 hp, contactor kicking around collecting dust?
Id like to avoid using 3 drum switchs plus a switch for the coolant. There is not a lot of places I can hang em.
Spindle motor has high and low..and I need to be able to reverse 2 of the input leads for forward and reverse. So Im going to need (1) reversing switch and a form 'C' switch (High/Low) just to run the spindle. Im sure Ive got reversing contactors....but so far I cant find a 3 phase C contactor in my gear. Lots of single phase...sigh.
I can stick a cabinet on the side of the mill and remote a set of low voltage switches to a small can on the knee or on top of the arbor support
Anyone got one, or a CHEAP source? Probably 12 amps..maybe 9....2.2-3kw
Thanks
Gunner
"I am for doing good to the poor, but I differ in opinion of the means. I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. In my youth I travelled much, and I observed in different countries, that the more public provisions were made for the poor the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer." -- Benjamin Franklin, /The Encouragement of Idleness/, 1766
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wrote:

Anyone have any better ideas on how to do this?
There has to be a better way.
Gunner
"I am for doing good to the poor, but I differ in opinion of the means. I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. In my youth I travelled much, and I observed in different countries, that the more public provisions were made for the poor the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer." -- Benjamin Franklin, /The Encouragement of Idleness/, 1766
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wrote:

Hummmm pondering this more...I could use 2 seperate relays, with a single SPDT switch, center off....couldnt I....hummm.......reversing relay to change wiring before feeding both relays.....hummmmmmm
Gunner
"I am for doing good to the poor, but I differ in opinion of the means. I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. In my youth I travelled much, and I observed in different countries, that the more public provisions were made for the poor the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer." -- Benjamin Franklin, /The Encouragement of Idleness/, 1766
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Gunner Asch wrote:

Been there. Found out that a 2 hp VFD is cheaper than a 2 speed 3 phase reversing switch. I chose the VFD.

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wrote:

That would mean I would also need a new motor.
Gunner

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Gunner Asch wrote:

Why? I used the old motor on my mill. Worked fine.
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wrote:

Because my motor has two sets of windings..a high speed and a low speed set. Not been reading?
Gunner
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Gunner Asch wrote:

Wire it for low speed, program the VFD for max frequency of 100-120 Hz. Worked for me, and yes, I've been reading.
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Gunner Asch wrote:

I don't believe there is such a thing as a high and low speed set of windings. I think they are all used for both speeds, but rearranged to double or halve the effective number of poles in the motor.
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wrote:

Hummm....interesting. Im going to have to study up on these sorts of motors a bit more.
Thanks!
Gunner
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Gunner Asch wrote:

http://www.uiitraining.com/b51a/100/15104ac_motor_rewind_intro7.htm http://www.uiitraining.com/b51a/100/15104ac_motor_rewind_intro8.htm
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wrote:

Hey..Thanks!! Bookmarked for close reading!!
Gunner
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Gunner Asch wrote:

Perhaps you cold drop in on the professional rebuilders in the Taft/Bakersfield area. There are several. Have a look in your local Yellow Pages directory. They all have experience and have been trained on both mechanical and electrical hardware.

No Prob. What you really need is a Boat Anchor guy.
--
John R. Carroll



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No... hard-wire it for high speed, and use the VFD to control it.
LLoyd
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On 2010-01-04, Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:

In the case of my "old to me" Clausing lathe, I could not do so because the motor had 220v only insulation which leaked current. If it was capable of being run by a VFD, that would have been the way to go. Gunner's mill seems to be of old vintage too, so he may have the same issue.
i
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On Mon, 04 Jan 2010 12:41:11 -0600, "Lloyd E. Sponenburgh"

Hummm..that is a thought. Though wiring it for low speed might be better. How often does one run a horizontal mill at 945 rpm?..or double the low speed freq?
Gunner
"I am for doing good to the poor, but I differ in opinion of the means. I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. In my youth I travelled much, and I observed in different countries, that the more public provisions were made for the poor the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer." -- Benjamin Franklin, /The Encouragement of Idleness/, 1766
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Wire it for low speed, for max torque. Run the VFD up to 120-180 Hertz to get up to the top speed. Or more HZ. At 120 Hz you are running the motor at rated speed, although on the low speed windings ( Sort of)
A two pole motor may have a N and S pole facing each other. A four pole motor would have N and N facing each other, and at 90 degrees, S and S poles facing each other..
The two speed motors work having two or four poles. ( but two pole windings) IIRC the four pole (low speed) operation is interesting, in that a pole pair is forced by the back iron. Not sure how to explain, good reading if interested. Basically, two opposing windings are both south poles ( for example) but pitched (spaced)far enough apart that a North pole appears between them from the back iron..
IOW a two pole motor can be forced to look like a four pole motor by reversing opposing poles, and thus forcing alternate poles in between them.
So with two windings, but with a narrower pitch to the coil, you can have either a two or a four pole field, with the back iron forming the third and fourth poles.
Anyway I said it was interesting how they did it.
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    [ ... ]

    [ ... ]

    Use two contactors on the output of the reversing contactor or drum switch -- with the two contactors controlled by a form C toggle switch. Ideally, you want a switch which will force a pause while switching from one to the other, so you don't wind up powering both windings at the same time. I would use one of the pull-to-unlock military arming toggle switches for the selection of speed.

    One low voltage switch for the speed selection. You can use a full drum switch for the forward/reverse switch -- or to control the reversing contactor (which probably is a latching style).

    Nope.
    Good Luck,         DoN.
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