# Please please help with a switch issue hooking up my 3 phase



## cincinnati JA (May 23, 2013)

Ok I have the 5hp rotary phase converter which is a 3 phase motor which is run of 2 legs single phase and the third leg is generated by the motor . Now the issue is I have a master electrician friend who bought me a fusible disconnect that is called a pull type . It is a good enclosure but I cannot use it as an on off switch or let's say I don't feel comfortable using it as a on off switch. So I went to a huge electrical supply store and talked with a card carrying electrician about a on off switch or start stop switch and I wanted it inline with the power going to the phase converter but he kept telling me that it wouldn't work that way. And blah blah he brought out this switch which looked exactly like what I wanted and I bought it and was happy but I pulled it apart and it is a momentary switch which I am assuming I must use a relay with . Which is fine but I have no idea how a momentary switch works with AC power . 

I think I understand that the momentary switch energizes the relay and starts the machine , maybe? But I'm still confused . Here are photos can someone please explain this to me . What I want, whether is be a momentary button or breaks type start stop, I want to be able to push start and stop to turn the machine on or off.



This is the inside of the phase converter I have close ups if anyone needs them .



These are the two switches the one on the left is a breaker type start and stop and the one on the right a momentary push to start . 





This is the inside of the breaker type switch this is for a three phase but can be used as a single phase as well. But I want to keep it on the shaper head with my Cincinnati mill. Obviously this type switch works with the power online to the motor... I don't know why that electrician was telling me switches can work this way. 







This is the inside of the momentary which I'm not exactly sure how this works so if someone could explain that would be awesome! But again I think I need a relay with this one .



This is the inside cover I've the disconnect 


Basically I have a fusible disconnect and I want a start stop switch in between that and the phase converter . Or should I just take out this disconnect and put a knife type disconnect and just use that as my on off to the converter ? No the converter did not come with its own on odd switch. When you apply power to it . It comes on . 

Please please help!


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## Tony Wells (May 23, 2013)

Please review the options in this document. There are example schematics in it that should help.

http://www.eriebearings.com/motor-control/files/eaton-motor-control-basic-wiring.pdf


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## cincinnati JA (May 23, 2013)

Tony Wells said:


> Please review the options in this document. There are example schematics in it that should help.
> 
> http://www.eriebearings.com/motor-control/files/eaton-motor-control-basic-wiring.pdf



Tony , first off thank you very much for that. I don't know much about electronics so even that article confuses me . I mean I can basically understand it but all of the schematics are for 3 phase momentary buttons . I need single phase 240v hook up going into a phase converter that generates a third leg "T3" I just read a thread on here and I am guessing I need a starter or a relay of some sort ? Maybe I should just get the knife type disconnect and move on!


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## Tony Wells (May 23, 2013)

Are you wanting control of the generated 3 phase with the start/stop station, or control of the phase converter?


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## Ulma Doctor (May 23, 2013)

if you were so inclined you could use the start/stop to operate a contactor or motor starter.
 that would effectively disconnect the main power when open.
your on/off switch doesn't appear to have the capacity to switch large inrushes of current or voltage.
the contactor or motor starter does have the capacity for large voltage/amperage inrush if sufficiently rated, to switch all power legs simultaneously. 
the on off switches would only switch control current to energize the contactor coil.


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## cincinnati JA (May 23, 2013)

Tony Wells said:


> Are you wanting control of the generated 3 phase with the start/stop station, or control of the phase converter?



I want to control the phase converter motor itself on or off. It will be a switch between the disconnect and the phase converter . After the converter it goes to a 3 phase panel and then from there my mill and my grinder will be hooked up and they have their own switches. In your opinion is a knife type disconnect ok to use as a on off switch on a regular basis or is it not ideal? I think I need to sit down and read the link you have me again and do some more educating of myself . It's a lot to take in . I wonder how much it would cost to buy a starter and a relay or if I can get away with just a relay ... Or from the photo of the converter can you see where a starter or relay would be to start the motor? Or 3rd option , just by a non fused knife switch to cut it on and tie it into the fused disconnect .

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Ulma Doctor said:


> if you were so inclined you could use the start/stop to operate a contactor or motor starter.
> that would effectively disconnect the main power when open.
> your on/off switch doesn't appear to have the capacity to switch large inrushes of current or voltage.
> the contactor or motor starter does have the capacity for large voltage/amperage inrush if sufficiently rated, to switch all power legs simultaneously.
> the on off switches would only switch control current to energize the contactor coil.



So I understand the breaker type switch not being able to carry the load but why? Because it cant withstand the consistant load And does the momentary allow it to carry the load because it is momentary ? So all I need is a motor contractor or starter in between the the switch and the wires to the lugs on the converter ? How would I choose what contractor or starter?
Also the breaker type was hooked up to the 3 phase shaper motor which was hooked up after the starter so is that why that switch can work as a on off on the motor?


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## cincinnati JA (May 23, 2013)

So I found this chart 

http://www.linkelectric.com/pdf/tools_starters.pdf

So it looks like I need a size 1 starter . And is this all I should need ?

Does it look like I have a starter on that phase converter? Top left


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## Tony Wells (May 23, 2013)

Since your phase converter is powered by single phase, you only need a 2 pole switch, or contactor.....whichever you choose. It is not necessary to have a contactor if you have a heavy enough switch, BUT, it would be more convenient to use one. In that case, you would set up your push button station to energize the coil on the 2 pole contactor (relay with heater). You will need to either use a contactor with an adjustable heater, or a properly sized fixed heater. 

Can you give us the make and model of the phase converter? I'd like to see the schematic for it before I give further advice.


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## Ulma Doctor (May 23, 2013)

So I understand the breaker type switch not being able to carry the load but why? Because it cant withstand the consistant load And does the momentary allow it to carry the load because it is momentary ? So all I need is a motor contractor or starter in between the the switch and the wires to the lugs on the converter ? How would I choose what contractor or starter?
Also the breaker type was hooked up to the 3 phase shaper motor which was hooked up after the starter so is that why that switch can work as a on off on the motor?[/QUOTE]

the breaker switch may not have sufficient capacity to carry the full motor load, you can still gain it's use you would just have to design the circuit differently than the momentary. just remember switching control circuits can be done with light duty switches, there is usually less than a couple amps involved.
 when switching motor loads there is potential to switch larger amounts of current, therefore the need for more robust parts.

yes, a contactor or motor starter of your choice can be installed to provide electrical control.

Starters can be rated in Horsepower or Amps drawn. i would suggest for economy to use definite purpose contactors whenever possible. they are widely used in the Air Conditioning,Refrigeration,and industrial applications way to numerous to list.
they are sturdy, cheap and available easily. 
i always over rate my contactors, if the circuit calls for a 15 amp, i install a 20 or 25 amp and they last for a long service life.
EBAY is packed with them.

that's correct, the breaker shut off all three phases at the same time. but there is no rule stating that you must use all three lugs at the same time. a single phase motor will pull a lot of current to start, even more current will be drawn by a 3 phase motor trying to start on single phase. once the pony motor is running current levels are dramatically reduced.
start up is the hardest part, once the pony is running the single phase we introduced to the motor is auto generating the third leg through induction, giving the 3rd phase


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## itsme_Bernie (May 23, 2013)

Tony Wells said:


> Please review the options in this document. There are example schematics in it that should help.
> 
> http://www.eriebearings.com/motor-control/files/eaton-motor-control-basic-wiring.pdf



Wow, that fills in some blanks!  Thanks Tony




Bernie


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## cincinnati JA (May 23, 2013)

Tony Wells said:


> Since your phase converter is powered by single phase, you only need a 2 pole switch, or contactor.....whichever you choose. It is not necessary to have a contactor if you have a heavy enough switch, BUT, it would be more convenient to use one. In that case, you would set up your push button station to energize the coil on the 2 pole contactor (relay with heater). You will need to either use a contactor with an adjustable heater, or a properly sized fixed heater.
> 
> Can you give us the make and model of the phase converter? I'd like to see the schematic for it before I give further advice.



Tony the make and model is here .

http://www.dempseyandco.com/phase_converters.htm

It's a local company and he did not give me a full schematic of the internals so tomorrow I am going to see him about it. I didn't realise motor starters cost so much money! 

Anyways I did a little research on the parts inside the converter and I'm learning a lot doing so. The item in the top left corner is a motor starter it is a Allen Bradley bulletin 709 size 1 , 3 phase starter . So it looks like I already have relays and a starter . The key is now if I can use this switch with it . That's why I want to go see the guy who built it. He is kinda of a simple guy so he may give me crap about wanting to use the extra push button station. I hope not because I will get a little irritated . Am I right in my thinking of having a separate start stop seperate from the fused disconnect ? 


Reading about why a motor starter is used it seems like their only purpose is to allow use of small buttons instead of a large switch and as a result they can put switches anywhere they want rather than have a big switch . With this phase converter being mounted to the wall and no need for the switch to be in a tight or small location there is no need . Although a motor starter still sits in the phase converter yet with no switches ... I just don't know enough . Hopefully tomorrow will shed some light .


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## Tony Wells (May 23, 2013)

Well, that's why I wanted to see the schematic. I'm sure the 3 pole starter in the converter is on the output, so you can energize the 3 phase distribution panel once the converter is fully at voltage and current. I have seen some shop built converters that have such a starter  and a simple spst toggle switch to energize the coil, and turn on the whole thing. That spst switch could easily be replaced with a pb station. The wiring of such does require access to the coil in the contactor, and knowing the coil operating voltage. If it is line voltage, fine, but if it is lower, and some (many?) are lower, like 24 volts.....then you will need a stepdown transformer that is controlled by the station, and is wired to the coil. There is a variety of ways to tackle this. One reason people use low voltage controls is so they can remote them. The converter can be wherever you want, and run a control circuit to where the buttons would be handy.

As far as a separate fused d/c, I do like the idea, but it's not really a necessity if you are running power to the converter from the supply protected by proper breakers. Nothing wrong with leaving it hot, as long as the contactor controls when it actually runs. But you do want a way to power it down for service. Code normally requires a safety disconnect within so many feet, or in line of sight, but in a private shop you can do whatever you feel safe doing. In my small shop, I don't use disconnects at each machine, but they are wired back to the breaker panel. Some of the machines have their own disconnects, some do not. If I want to work on it, I simply kill the breaker. I don't do a LOTO, because it's just me. On my equipment outside, like the air compressor and air conditioner, yes, they have breakers in the panels, and they have fused disconnects adjacent to the equipment. I'll look over the link and see if I can offer anything else.


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## Tony Wells (May 23, 2013)

Looking at the link info, I'd say that contactor is not for control of the entire unit, but for engaging some of the balancing circuitry. I wouldn't count on it being available for what you want. If I were setting this up, knowing only what I do at this point, I'd get a 2 pole contactor, 5 hp and the PB station you have. Run your power from the service panel to it (properly breakered) and turn the converter on and off with it, and forget about a knife switch or a disconnect. You could get something that would fit in a small enclosure and mount the PB station right on it, wherever you wanted to.


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## Tony Wells (May 24, 2013)

OK, so you feed single phase in and it just goes through and on the output terminals, there are three, with the added phase. So when you power up the unit, you simply switch on the single phase 220? If that's the case, then you certainly could use a fused disconnect (2 pole) to control it. BUT, where is the protection for the output? I would think there is some built in, or I would most certainly have something as a main breaker in the three phase panel this feeds.


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## cincinnati JA (May 24, 2013)

Tony Wells said:


> Well, that's why I wanted to see the schematic. I'm sure the 3 pole starter in the converter is on the output, so you can energize the 3 phase distribution panel once the converter is fully at voltage and current. I have seen some shop built converters that have such a starter  and a simple spst toggle switch to energize the coil, and turn on the whole thing. That spst switch could easily be replaced with a pb station. The wiring of such does require access to the coil in the contactor, and knowing the coil operating voltage. If it is line voltage, fine, but if it is lower, and some (many?) are lower, like 24 volts.....then you will need a stepdown transformer that is controlled by the station, and is wired to the coil. There is a variety of ways to tackle this. One reason people use low voltage controls is so they can remote them. The converter can be wherever you want, and run a control circuit to where the buttons would be handy.
> 
> As far as a separate fused d/c, I do like the idea, but it's not really a necessity if you are running power to the converter from the supply protected by proper breakers. Nothing wrong with leaving it hot, as long as the contactor controls when it actually runs. But you do want a way to power it down for service. Code normally requires a safety disconnect within so many feet, or in line of sight, but in a private shop you can do whatever you feel safe doing. In my small shop, I don't use disconnects at each machine, but they are wired back to the breaker panel. Some of the machines have their own disconnects, some do not. If I want to work on it, I simply kill the breaker. I don't do a LOTO, because it's just me. On my equipment outside, like the air compressor and air conditioner, yes, they have breakers in the panels, and they have fused disconnects adjacent to the equipment. I'll look over the link and see if I can offer anything else.



Thanks Tony, I'm learning more and more as you guys provide this wonderful information. The way this converter is set up to work is the L1 and L2 leg feed into the panel seperate or daisy chain off the lugs in the converter . There is no input output separation inside this converter . And then the T3 is added . So what would the motor starter be doing on the output end ?  I see wires coming off of it going to the two black capacitors on the left . And there is also a time delay involved . As far as the fused disconnect goes , I was specifically told to NOT use a breaker on this converter because of its high start amperage it draws so the motor doesn't trip the breakers or blow fuses. I'm sure you are familiar with time delay fuses . That is something I do understand lol.   I really like the idea of the momentary switch but I may just swap out the pull out disconnect for the lever type/knife type fusible . I still have my millingmachine to refurbish so I gotta save some money. Unless I could get the parts I needed used for next to nothing .

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Tony Wells said:


> Looking at the link info, I'd say that contactor is not for control of the entire unit, but for engaging some of the balancing circuitry. I wouldn't count on it being available for what you want. If I were setting this up, knowing only what I do at this point, I'd get a 2 pole contactor, 5 hp and the PB station you have. Run your power from the service panel to it (properly breakered) and turn the converter on and off with it, and forget about a knife switch or a disconnect. You could get something that would fit in a small enclosure and mount the PB station right on it, wherever you wanted to.



Btw my electrical set up is interesting . There is 8gauge wire feeding the garage seperate from the house off a 60amp breaker which feeds a fuse box . And the garage is all wired with 12 gauge . So from the fuse panel with 30 amp fuses it goes into the fusible disconnect that holds the time delay fuses for the reasons I said in the previous post. From there the phase converter is turned on and then the output "t3" a long with L1 and L2 is fed into the 3 phase panel and from there I will hook my machines to that.


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## cnczone (May 24, 2013)

This is a great thread - http://www.cnczone.com/forums/phase_converters_vfd/137647-3_phase_motor_wiring.html and this one http://www.cnczone.com/forums/phase_converters_vfd/40228-make_3_phase_converter_-.html


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## cincinnati JA (May 24, 2013)

Btw the breaker type switch is rated for that 1/2hp shaper head so that's why it can take the amps.  Here is a photo 
	

		
			
		

		
	




Is the momentary switch I got worth 42$ ? If its a good deal I will keep it for future projects but if not then it maybe should be returned . It was new old stock. It's a joslyn Clark pushbutton station Bul. 100 type ee std duty 600v max cat. No. 1A 3 ... Any of you guys know what that means? 

I may just go with the knife switch and be done with it . 

But I also have some questions about another piece of 3 phase equipment I have since we are on the subject of switches . It is a Allen Bradley and is its own manual starter switch all in one . 




Here is the description on the back of the cover .




It uses N18 type heaters which calls for max fuse size 10 . Would this means it can take up to 10 amps on this fuse? I will be hooking this machine up to a 15amp 3 phase breaker . Will this be fine? 

So if I find a pushbutton station like this AB one . It should work for the converter as well right ?


If I choose to use contractors is this what you were talking about ?

http://www.auberins.com/index.php?main_page=product_info&products_id=164


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## GK1918 (May 24, 2013)

I was told not to cause of high amp start load??  You want to start & stop the RPC fed by 220 single
phase?  I like the looks of a red & green switch that has to have a relay (we all like the looks)?
I have seen in the past push button red & green switches that are actually a knife switch.  And then
whats wrong with the ole gray D box with double 100amp breakers.  My 220 has this type box next
to my enterance door, so on the way out I shut down all 220 because my kids always leave the air
on and the comp. will run all night.  I thought I fell off the boat on this one, but rethinking I do have
two new st/stop with green and red.  When either is pushed (it does not stay) tells me it triggers
a relay (which I have) that when closed it stays closed until stop is pushed that relaxes a coil that
kept it closed.  I Think.   Ill try and look for it I know its rated 600vts.  Its probably the same deal as
on the mill control panel.  Still think Id go for a simple double breaker, after all thats my shop shut down
it takes all the machine start shock (although it is a sub box off the main breaker.  I do not have RPC
so its my guess Josh, but I have a freind that does he has just a 220 breaker on the 3Ph motor and
a 110 common home switch on the pony 110 motor <  > he flips the pony first= flips the 220 gets the
220 running and flips off the 110 pony just like starting the old Cat Dozers.  Since we last spoke I
have not yet had any problems with my static phase and a little proof, other day had to drill a spring
hanger none of my presses wont go that slow so the mill & the drill caught and smoked the drive 
belt.  So I dont know about that 2/3 Hp thing, I got plenty of power.         Sam


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## cincinnati JA (May 24, 2013)

GK1918 said:


> I was told not to cause of high amp start load??  You want to start & stop the RPC fed by 220 single
> phase?  I like the looks of a red & green switch that has to have a relay (we all like the looks)?
> I have seen in the past push button red & green switches that are actually a knife switch.  And then
> whats wrong with the ole gray D box with double 100amp breakers.  My 220 has this type box next
> ...



Well Sam I am probably super protected because I'm protected by time delay fuses which are required for my specific RPC , a fuse panel, then a breaker in the house lol. I can shut down my garage from my house of need be its 100 feet away from the house. 

Anyways about your static phase converter . The best known claim on the static converter is 70% of HP marked on the motor but that's not to say someone went crazy with some extra run capacitors and its pushing more . I just spoke with a guy who claims he is only getting 10% loss on static that he built . But again static only allows for one motor to run at one time. With my cross feed I needed at least two three phase motors to run at once needing a RPC or Solid state digital converter . I have a balanced RPC which is very very good with little power fluctuation it is no more than .5 +/- I believe . This type of RPC has no motor HP loss. An unbalanced RPC has about 10% loss . You friend has a traditional style RPC with a pony motor starting up a generator . I have a 5hp 3phase motor that needs to be started up but runs off single phase and the 3rd winding acts as a generator generating the 3rd leg . So you can see why I need certain switches and Definatly time delay fuses . The start up amps on a 5hp 3phase motor are greater than the fuses/breakers recommended for the motor so this is why you use time delay so at start up the fuses won't blow and you don't use breakers because they would just always trip. 

A balanced RPC isn't cheap so I am making sure I buy all the proper parts to hook this up to get maximum efficiency and life. This particular unit allows me to draw 15amps of three phase power so I can run a few machines at one time . When it comes to electricity I ultra respect it . I've been shocked a few times and I don't like it one bit! I also have never liked using disconnects other than to shut down power for service . It's just how I am I guess . Want things just a certain way . Probably hurts and helps at the same time hah .


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## Ulma Doctor (May 24, 2013)

A balanced RPC isn't cheap so I am making sure I buy all the proper parts to hook this up to get maximum efficiency and life. .[/QUOTE]


to the contrary,
 a balanced rpc can be achieved by adding a couple of Run Capacitors between phases. 
i recently balanced a 7.5 hp RPC for less than $35 in capacitors. it really doesn't get much cheaper.

for reference, a 5 hp RPC can be made more efficient by adding an 80uf  run cap between the generated leg and 1 hot leg.
then add a 60uf run cap between the 2 hot legs , you'll see the voltage will be within 10% between legs loaded.
 10% is considered balanced.


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## cincinnati JA (May 24, 2013)

Ulma Doctor said:


> A balanced RPC isn't cheap so I am making sure I buy all the proper parts to hook this up to get maximum efficiency and life. .




to the contrary,
 a balanced rpc can be achieved by adding a couple of Run Capacitors between phases. 
i recently balanced a 7.5 hp RPC for less than $35 in capacitors. it really doesn't get much cheaper.

for reference, a 5 hp RPC can be made more efficient by adding an 80uf  run cap between the generated leg and 1 hot leg.
then add a 60uf run cap between the 2 hot legs , you'll see the voltage will be within 10% between legs loaded.
 10% is considered balanced.[/QUOTE]

Well considering I didn't build it . It cost me $450 which is a pretty good deal but still a good chunk of change so I don't want to screw it up. I just met with the owner and builder today and he explained about how all the parts work . The motor starter in the unit is to allow the starter caps to be on and then cut off and it is controlled with the relays . And like you said the run capacitors help to balance the power . So it was pretty interesting to learn about it all! The time delay switch in there is for the start caps as well. 

I returned the momentary switch because I really didn't need it or the extra cost of buying contractors and heaters . I guess I could have done some salvage finds but really I just needed the disconnect . I bought a knife type disconnect which was fusible and put the 20amp fusetronic time delay fuses in it and I will control the RPC with that. Maybe one day I will try my hand at building a RPC for the fun of it. I will need another one in the larger shop I'm building behind my garage . I really learned a lot In the past night! Thank you guys for helping me out. I will post photos after I get it all hooked up . I'm building the frame to mount the motor on the wall tonight or tomorrow .


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## Pmedic828 (May 25, 2013)

Did anyone think about using a compressor relay found in the outside portion of a central air conditioner?  You can use 1 pole of the relay for 120V and both for 220V.  The coil that controls the relay is usually 12 or 24 volts.  You can use a toggle switch and a small 110V to 24 volt transformer to apply current that will energize the relay coil.  This in turn will pull up the relay.  You can get a small transformer for under $10 and switch under $5.  Connect the neutral and hot wire to a cord set to plug in and the other side to the input side of the transformer (110V) using a switch on the hot side.  Connect motor leads to common and side of relay.  When energized, the coil will pull in the relay as long as the switch is in the on position, thus pulling the relay in and connecting the motor.  When the 24 volt coil is turned off, the relay drops out isolating the motor.  Hope this helps!


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## GK1918 (May 25, 2013)

*Back to reply #19*

I misread somewhere, but when you said about my freinds setup >>I now got it (problem).  Back to the
static,,  Mine runs fine with all four motors at the same time. But I have to first start the main motor,
seems that acts as a generator for the other three, once all are running I can shut down the main
and the others keep running.  Example other day -start main-start coolant pump-shut off main and
I sucked coolant out in a pail (im changing the coolant to new)  All I can say it took awhile but the 
pump ran and ran didnt even get warm, so I dont know, but it works fine.  sam


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## excel777 (May 27, 2013)

Just saw your post. You probably have it figured out by now, but here's my two cents. I have a 5 hp rotary phase converter and was faced with a similar problem. Converter came with a knife disconnect switch and a drum switch attached to start the converter. Had to rotate drum switch then engage knife switch. Big pain and lousy engineering. I use a Cutler Hammer on/off monetary switch remotely in my chip equipment room 25 feet away. Ran 5 wires to it from a magnetic contactor, which controlled current to the disconnect box which is always on, through the fuses and on to the converter. Really simple and been working for the last 8 years with no problems. I don't think the drum switch is even connected now. If you need any info in detail, I could take some pictures and forward or attempt to post here. I have a 5 connection mag contactor, while you have a 4 connection. I can't remember if I used all five, but believe I carried 2 wires down to the disconnect box. I'll have to look to be sure. Been a long time since I wired it up.


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