Power Switch Upgrade

[texjames]

New guy first post. I have a old U.S. Machines Vertical Mill i been learning on.
having a blast with it.It has some really old tech power switch i'd like to upgrade to something better.See the pics below.Power comes off the phase converter to switch, then go's to motor, another cable running up through
belt cover hood on top go's to reverse switch.Any idea's on a better power switch? Thanks!


Here below my oldie goldie...needs lots of TLC and those yellow wheels got to go soon...

[DFMiller]

Nice looking machine. Welcome aboard.
I got lost looking at the wiring. The disconnect (Orange box) is connected where? Between the incoming power and the phase convertor or the phase converter and the motor. I noticed that one of the fuses is missing and maybe jumpered out.
If I were doing it would have some kind of disconnect on he phase convertor and then a properly sized 3 phase power switch to the motor. What is the nameplate on the motor and the phase convertor say?

[texjames]

Nice looking machine. Welcome aboard.
I got lost looking at the wiring. The disconnect (Orange box) is connected where? Between the incoming power and the phase convertor or the phase converter and the motor. I noticed that one of the fuses is missing and maybe jumpered out.
If I were doing it would have some kind of disconnect on he phase convertor and then a properly sized 3 phase power switch to the motor. What is the nameplate on the motor and the phase convertor say?

It has a Phase-a-matic converter Model PAM-200 rated for 3/4 to 1 1/2 HP motor.My motor plate info is long gone but others i've talked to seem to think these had about 1 HP motors.Here is a link to the Phase-a-matic and its doe's say not to run through fuses after the converter.It says in the instructions a magnetic starter is preferred.I'm really lost on the electrical part of this, Link to Phase a matic...
http://www.phase-a-matic.com/PDF/SIS.pdf

[DFMiller]

A switch like this will fit the bill.
http://www.grizzly.com/products/Magn...nly-2-HP/G4672
I always like to go bigger if size is in question.
I am still unclear. Did someone just jumper out the fuses to suit the requirements of the phase convertor?
A tidy up of the wiring when the switch is added.
The reason a magnetic starter is recommended is so once it's off due to source breakers tripping, power failure etc the machine will no start back up when the power is restored.
I am all for giving most things a go but if you are not really comfortable with electrics finding some one who is is a great idea.
I hope you get lots of enjoyment out of the machine. It looks like fun.
Dave

[justanengineer]

Knife switches are still in common use today, theres nothing "old tech" about them. The entire purpose of that switch is simply to disconnect power to the machine completely so that the electrical system can be worked on. The purpose of the fuses inside are the same as a circuit breaker or fuse box, to prevent the machine from drawing too much power. All that being said, the power should come from the wall, into the knife switch/orange fuse box, then go to the converter, then to the motor.

[DFMiller]

I did not see the knife switch as it was hidden in the orange paint. ;-) my excuse is looking at pictures on 10.1" screen. Nothing wrong with it as a disconnect. If I recall they are not rated for many cycles of interrupting of the power at full rated load but for as just.... Disconnecting for isolation. If there is no other off / on switch something like I suggested will fit the bill.
Dave

[texjames]

I was looking at the magnetic switches and had a thought.What about a single phase magnetic switch before going into the converter.Then i could do away with the knife switch box and clean up the wiring. I've done some wiring but might get a pro to rig this up however.

[winchman]

Maybe you need something like this and a transformer to provide the power for the contactor coil.



It's a 3-phase magnetic contactor salvaged from a large AC unit.

[DFMiller]

I guess that could work. A 220 switch is a double pole and a 3 phase has 3. I guess you would save a bit. Whether you could mount it in a convienent position is another question. I would put it in an easy to get position for those "Oh Crap" moments.
Asking a pro never hurts. I don't know where you are but some places are very strict about codes and inspection. Even if it's never going to be inspected there is nothing wrong with doing it properly.

I am using roto phase on my small mill. It had reversing switch on the machine. I just used a disconnect.

Best of luck and post the results. We all like pictures.
Dave

[justanengineer]

I would recommend you keep the knife switch/fuse box arrangement and rewire it so the fuses are operational. If youre anything like me, then you have a LARGE breaker in the wall for welders or other machinery so the added protection of having fuses sized for the machine's motor would be well worth it. Also, the knife switch is useful not only for working on the machine, but also as a safety backup - flip the switch at the end of the night and the risk of an electrical fire, kids playing with it, etc etc are eliminated. Many shops do a similar trick at night by cutting power to all machines via a master switch. Its a very good habit to get into.