# Is this a 3 Phase Static Converter?



## Uglydog (Jul 17, 2013)

I stumbled on a Wells 8M where I purchase my steel (an old farm).
They couldn't remember when it last ran, or the details of where it came from. Been in the barn next to other unused farm machinery. 
$100, if I promised to do some more fab work for them. He threw in 4each 600lb casters. 
It looks much better now than it did when I picked it up.
It has coolant tray and a pump.
Everything seems to spin. The Blade guides need serious cleaning up, and likely new bearings. 
Peerless 220v, 3phase, 2.4amp motor.

Anyway....

The electrical line in runs to this box (mentally rotate the pic 45" Clockwise). 
Wires out of the box run to the coolant pump and motor.
There is no plug on the saw.

If it would be helpful I can remove the capacitors(?) and let you know what is printed on them.

Is this a static converter? Can I hook this up directly to 220v 1ph?
Or is it just a 3ph starter switch?
Something else?

Any input would be helpful.

Thank you,
Daryl
MN


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## Ulma Doctor (Jul 17, 2013)

I'm having a hard time seeing how it's wired up, but it could be a static converter
but i can't say for sure.
make sure you discharge the caps before you attempt sticking your hands in there!!
i would venture to guess it is if the motor is 3 phase though

If you were to put single phase 220 v to the lower 3 wire(conductor) cable , black 1 leg of the 220 white or red will go to the other 220 hot leg.
green would be used for ground

the upper wire coming into the box will have 4 conductors if it is a static converter, that goes to the 3 phase motor if i'm seeing it correctly.
on leg will not measure voltage until the contactor is pulled in, then 3 phases will come out of the upper wires !!


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## pineyfolks (Jul 17, 2013)

Nice saw, your inventory of equipment is growing! I can't help with wiring I'm color blind, when I do wiring I have my wife tell me the colors and then I tape the names on them so I can make the connections. I try to stay on her good side while wiring.


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## raross61 (Jul 17, 2013)

Uglydog said:


> I stumbled on a Wells 8M where I purchase my steel (an old farm).
> They couldn't remember when it last ran, or the details of where it came from. Been in the barn next to other unused farm machinery.
> $100, if I promised to do some more fab work for them. He threw in 4each 600lb casters.
> It looks much better now than it did when I picked it up.
> ...




I think this is a static convertor but I am unsure of the brand, might go to google images, and page thru the pictures, and see if you can find a match. This is not a 3 phase motor contactor/starter set up. We have 480 v 3 phase at work, and I connect them all the time. The normal 3 phase starter contactor has a thermal protection device, old ones have three heaters (sized to the motor), attached to the protection block, and when they get to hot they will disconnect the motor legs from the line. The new ones we have are electronic, and have a couple of adjustment wheels for settings, reset, test etc. Very close to the one's in a lot of these smaller lathes we have, only way bigger! The motor starter, unless it is a full manual setup, has a contactor also, basically a huge relay only it has 3 legs, they use many control voltages for the coil that controls the contactor, on most setups it is a lower voltage, 24v, 120v, 240v, etc, also some can be ordered ac or dc voltage. I have never seen a capacitor, in any commercial 3 phase motor starter!    Bob in Oregon

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raross61 said:


> I think this is a static convertor but I am unsure of the brand, might go to google images, and page thru the pictures, and see if you can find a match. This is not a 3 phase motor contactor/starter set up. We have 480 v 3 phase at work, and I connect them all the time. The normal 3 phase starter contactor has a thermal protection device, old ones have three heaters (sized to the motor), attached to the protection block, and when they get to hot they will disconnect the motor legs from the line. The new ones we have are electronic, and have a couple of adjustment wheels for settings, reset, test etc. Very close to the one's in a lot of these smaller lathes we have, only way bigger! The motor starter, unless it is a full manual setup, has a contactor also, basically a huge relay only it has 3 legs, they use many control voltages for the coil that controls the contactor, on most setups it is a lower voltage, 24v, 120v, 240v, etc, also some can be ordered ac or dc voltage. I have never seen a capacitor, in any commercial 3 phase motor starter! Bob in Oregon



Here is a picture of a basic 3 phase motor starter. Bob

BTW when the heaters trip out, there is a little dog in there that is connected in various ways to a RESET button, when you push the RESET they dog back in and connect the power again, after the thermal heaters trip.


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## Ulma Doctor (Jul 17, 2013)

also some can be ordered ac or dc voltage. I have never seen a capacitor, in any commercial 3 phase motor starter!    Bob in Oregon[/QUOTE]

HI Bob
The Phase A Matic uses a capacitor to give the 3 phase motor a one time shot of DC voltage to provide high potential difference to get the motor started, after the motor starts, the 3 rd leg is generated by the rotating motor and the phasamatic, then stores the capacitor charge to start the motor the next time it is called to do so.
There are a few other brands that operate from the same principle.


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## Uglydog (Jul 17, 2013)

raross61 said:


> BTW when the heaters trip out, there is a little dog in there that is connected in various ways to a RESET button, when you push the RESET they dog back in and connect the power again, after the thermal heaters trip.



Perhaps that is what is going on with my Gisholt.
She has a 10hp 3phase.
She starts fine, runs well.
Then she shuts down.
Seems to restart well. However, doesn't run to long before she shuts down again.
I figured it had something to do with electrical demand in the area as I started having trouble when it got hot and most homeowners started their Air Conditioners. 

How can I best test to learn if this is the problem?

Thank you,
Daryl
MN


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## raross61 (Jul 18, 2013)

Uglydog said:


> Perhaps that is what is going on with my Gisholt.
> She has a 10hp 3phase.
> She starts fine, runs well.
> Then she shuts down.
> ...



Daryl,
I do a lot of standard 3 phase stuff but not very much with these “static converters”. The Ulma Doc sent me a e-mail and we had a good chat about this. May I suggest you Google the phase-a-matic site it goes into these in detail. Keep in mind what the site is saying about these they are for light or moderate use. This saw I would say would be a good candidate for the device, and I say that is what is in the picture you posted, just unsure of the manufacturer. Ulma Doc is right the normal 220 VAC single phase should be green is ground, black and white are the 220 VAC legs, could be black and red for the (input legs). He gave me a overview on how they work and the site also does a pretty good explanation. The motor starts on the capacitors, like a regular single phase motor without the centrifugal switch. Then the way I read it the capacitors disconnect, and the windings in the motor you are running, somehow make the third leg, or keep it running. So bottom line here is the 3 phase motor is running, but not on true 3 phase, and not at full power! So the site talks about various motors and how much it will de-rate them, it also talks about mechanical means to decrease the load on the motor, Example: Changing pulleys. Gears, etc. 
The only options I run on a everyday basis are:
480 VAC 3 Phase
220 VAC Single Phase
220 VAC 3 Phase motors running on a VFD drive.
     Now by the looks of things on the site you are getting quite a bit of iron, also no offense but, you sound like myself where you are digging up a lot of buy’s , and deals, that’s a good thing! You may want to consider setting up 4 or 5 machines, off a dedicated 3 phase branch setup/system. You can also check with the local power company, sometimes good, sometimes bad, if 3 phase is on the street, it could be doable, most houses do not have the 3 phase leg, even on the highline feeding the transformer to the homes. So they usually have one of two things going, you pay the entire cost to get the highline down the street or wherever the 3 phase stopped closest to your shop. Sometimes they will work with you if you can guarantee you will be using a certain amount of power, usually if the $2500-$5000 a month range! Your state may be different but that’s the way it goes here in Oregon. The phase-a-matic site also talks about using there controller to slave another motor onto the line and make the 3[SUP]rd[/SUP] leg of the three phase of the “Slave Non Operating Motor”. With that setup you have a actual 3[SUP]rd[/SUP] leg, 3 phase system! I would be on the look out for some 3 phase disconnects, in the future. That way when you wire your shop, you don’t have too but it is nice to have a disconnect at each machine, thermal overloads are nice also. The disconnects look pretty much like any you see in a home, but there will be 3 feed wire L1,L2,L3, and normally, a ground buss bar on one side. If the disconnect has thermal overloads in it will have 3 heaters in it one for each leg, the each usually have 2 flat head screws on each end. If its electronic it will usually have a couple of small dials trimmer pots, for the amp setting, and usually a Red reset button. So to summarize this the only to ways I know to get actual 3 phase power are: 1 A rotary Phase Converter 2. 3 Phase off the highline.
　
    On the other problem of the machine shutting down . You need to figure out what kind of converter do you have and what is the rating? Also do you know how to use a inductive amp meter, and do you have one? Remember the 3 phase motors start and run due to the rotation of the phases, that is why when you swap any two leads the motor will rotate the opposite direction! But due to the nature of this motor and wiring design, if you have good connections, and good windings in the motor, the amp draw on each leg should be very close to the same on each leg! My 30 HP Quincy compressor would be like 47.1 , 47.4 , 46.9, they are not all PERFECT but pretty equal. So when one leg is dropping out the other 2 will try to make it up, and that can cause too much load and trip thermals, fuses etc. So you need to check all three legs to your motor running, record the readings, and then see 1 are they close to the same? 2 If yes are the running right at the limit of you 3 phase converter? IE 14.9 on a 15 amp static converter?
Bob in Oregon

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Uglydog said:


> Perhaps that is what is going on with my Gisholt.
> She has a 10hp 3phase.
> She starts fine, runs well.
> Then she shuts down.
> ...



I posted some help in another post, but one more thing, you may want to test the input voltage to your converter. May also help to check it at various times during the day when you think the demand will be the most. Might help to make sure you have pretty steady input power to the converter!

                                            Bob in Oregon

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raross61 said:


> Daryl,
> I do a lot of standard 3 phase stuff but not very much with these “static converters”. The Ulma Doc sent me a e-mail and we had a good chat about this. May I suggest you Google the phase-a-matic site it goes into these in detail. Keep in mind what the site is saying about these they are for light or moderate use. This saw I would say would be a good candidate for the device, and I say that is what is in the picture you posted, just unsure of the manufacturer. Ulma Doc is right the normal 220 VAC single phase should be green is ground, black and white are the 220 VAC legs, could be black and red for the (input legs). He gave me a overview on how they work and the site also does a pretty good explanation. The motor starts on the capacitors, like a regular single phase motor without the centrifugal switch. Then the way I read it the capacitors disconnect, and the windings in the motor you are running, somehow make the third leg, or keep it running. So bottom line here is the 3 phase motor is running, but not on true 3 phase, and not at full power! So the site talks about various motors and how much it will de-rate them, it also talks about mechanical means to decrease the load on the motor, Example: Changing pulleys. Gears, etc.
> The only options I run on a everyday basis are:
> 480 VAC 3 Phase
> ...



Let me clarify one thing, you could run twist lock, 4 wire plugs to each machine, if they are all the same amperage, they probably wont be! So I would suggest a fused disconnect at each machine, with thermals is the best to protect each machine, sorry its a little more up front but way better latter on. When people upgrade machine's a lot of times they go from the wall out and just toss the old disconnects!

                                         Bob in Oregon

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Oops just so you know the inductive ampmeter has a loop and goes around each line one at a time to read the AMPS, so the 46 and 47 numbers are the AMP load on each line.    Bob


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## Ulma Doctor (Jul 18, 2013)

To add to Bob's summirization...

The third leg in Daryl's system is being induced by the motor while the motor is running.
 single phase power is supplied to the motor at all times the contactor is pulled in, then the 3rd leg is induced.
the 3rd leg will have lower voltage than the other 2, if there is not a capacitor on leg 3 for balance, you may wish to install one.
i can help you identify, choose, and install a cap for this purpose should you need any help

there are 5 ways i know how to get 3 phase power..
1) good old 3 phase supply from the power company
2) 3 phase transformer operated by single phase
3) RPC, single phase input, 3 phase output
4) VFD, single phase input 3 phase output
5) Inversion, non variable single phase in 3 phase out without frequency control.

there are probably others but none come to mind right now.

I'm happy to help out, drop me a line if you need further assistance


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## Uglydog (Jul 18, 2013)

raross61 said:


> Let me clarify one thing, you could run twist lock, 4 wire plugs to each  machine, if they are all the same amperage, they probably wont be! So I  would suggest a fused disconnect at each machine, with thermals is the  best to protect each machine, sorry its a little more up front but way  better latter on. When people upgrade machine's a lot of times they go  from the wall out and just toss the old disconnects!



Bob and Ulma Doc,
Thank you for your considered response.
I believe I actually understood it (that is not to suggest that I could do it). With the exception of the above.

Can I run 4 wire twist locks and still have "thermals"? I've got a large box full of 3phase and 1phase twist lock plugs.
Is a "thermal" a fuse?
Is a "fused disconnect" a small sub panel with a circuit breaker?

I've got an Ohm Meter, a gift from an electronics guy many years ago, supposedly a good one. No idea how to use it, other than for continuity checks.  
I'd like to get the Gisholt electrical problem resolved. Up until May I could run it all day without any interruptions. 


Thank you,
Daryl
MN


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## Uglydog (Jul 18, 2013)

Wired her up. 
After the dust cloud cleared from the motor vents (hmm... doesn't smell like smoke), she purrs like a kitten.

Thanks for your help!!

Daryl 
MN


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## Ulma Doctor (Jul 18, 2013)

Can I run 4 wire twist locks and still have "thermals"? I've got a large box full of 3phase and 1phase twist lock plugs.
A) you will only need a single phase plug for input power to the converter box, the twist lock will not interfere with heater selection or use.

Is a "thermal" a fuse? 
A)NO,Daryl. a thermal is a device that breaks electrical contact when the circuit is pulling too much current. they are also called heaters.

Is a "fused disconnect" a small sub panel with a circuit breaker? 
A)Fused disconnect by definition uses fuses to disconnect an overloaded circuit. a breaker provides the same function but rather than have a replaceable overload it has a manually reset one.

I've got an Ohm Meter, a gift from an electronics guy many years ago, supposedly a good one. No idea how to use it, other than for continuity checks.  
I'd like to get the Gisholt electrical problem resolved. Up until May I could run it all day without any interruptions. 
A) Daryl you may want to take a look and an amp draw on the Gisholt motor, the thermal overload may be tripping if the motor gets too hot. Remember that as a motor heats up the windings inside are less efficient at carrying electricity, the more resistance the less performance is possible.

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Uglydog said:


> Wired her up.
> After the dust cloud cleared from the motor vents (hmm... doesn't smell like smoke), she purrs like a kitten.
> 
> Thanks for your help!!
> ...



Glad to hear she's up and running
how does she sound???
Have you attempted an amp draw test??
mike


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## raross61 (Jul 18, 2013)

Uglydog said:


> Bob and Ulma Doc,
> Thank you for your considered response.
> I believe I actually understood it (that is not to suggest that I could do it). With the exception of the above.
> 
> ...



Daryl,

      I think we can help you but we need more info here, I am asuming the Gisholt is also a 3 phase machine with a converter, if so what type of converter? or is it single phase? Does it start again on it's own after it quits, with you doing nothing other than restarting it with the switch? IE: Do you have to push a reset button to get it going again?

                                          Bob in Oregon


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## rdhem2 (Jul 20, 2013)

Could you provide the information stamped into the label on the motor?

That should provide the Frame size, voltage, amperage, horsepower, and phase.

In my humble experience from what I see in the picture is a contactor, a plastic cased *STARTING *capacitor and a metal cased *RUNNING* capacitor, and nothing else.  This indicates a single phase unit.  This is why we need nameplate information as some units made to supply third leg power use the same components.  I paid almost $200 for one to operate a 1/2hp drill press, nothing but a pain in the a$$.  Would stall out, would not start, just rattle and buzz sometimes and when I talked to the maker he said I could not return it as they did not accept "USED" electrical devices.  How is that for a kicker?  I then spent $235 for a 1ph to 3ph VFD and the world is great.  Plus I now have infinite speed control, overload protection, and reversing at the tip of my fingers.

What all did you do to get it to run?


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## Uglydog (Jul 20, 2013)

rdhem2 said:


> Could you provide the information stamped into the label on the motor?
> 
> That should provide the Frame size, voltage, amperage, horsepower, and phase.
> 
> ...



Blew large dust clouds out of the motor vents (more came out when the motor started), made sure she was grounded, attached a 220v 20amp 1ph plug to the line (green is ground), got the fire extinguisher ready, plugged her in and flipped the switch.


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## raross61 (Jul 20, 2013)

rdhem2 said:


> Could you provide the information stamped into the label on the motor?
> 
> That should provide the Frame size, voltage, amperage, horsepower, and phase.
> 
> ...



If I may ask what brand VFD are you running? Are you happy with it then? Easy to program? I want to get a good one the first time, I have been considering the TECO brand?

                                                  Bob in Oregon


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## rdhem2 (Jul 21, 2013)

I have used many brands.  Probably my favorites are Allan Bradley and Telemequnec, (new name for Square D).  I have never used a TECO but from what I hear and read they are a pretty good unit.  Lets face it, any brand is only as good as the man you buy it from.  If they back their product one hundred percent then you will be happy because the outcome will be positive.  TECO I believe is a Westinghouse product.  I am a retired electrical contractor who primarily dealt with industrial accounts.  The customer usually supplied the VFD and we merely installed and programmed them.  Yes Sir.  Installer of many, Master of none.

My shop has both the AB and Tele units and I can not brag one over the other.  The AB does have a few little features that make them more user friendly to non professionals.  I use five, Rockwell band saw, Bridgeport mill, home made wood lathe from a junky Craftsman, Walker Turner radial drill, and Delta drill press.  I used some for the speed control such as the wood lathe and mostly the others to get three phase from single.  

Jump in and try the water, you will love it and if you have problems I would be glad to help.  If I don't know how to fix the problem I can usually ask the right question the right way to get the answer.  I have never given up yet!  Send me a personal message if you wish as I don't always check back to all the same places.

Good luck and good machining!


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## Uglydog (Jul 21, 2013)

Found what is labeled a "thermal" in the Gisholt's electrical panel next to the magnetic switch. There are two thermals. 
One of them has little bubbles/blisters on the sides. Similar to what you would expect from paint that has gotten hot.
I expect this is a problem.

Next question:
What causes a thermal to go bad?
Do they age out?
Will a new one burn out due to the real problem?
How do I best learn the real problem?

From this thread it could be the incoming power, my phase converter, or the motor.

Guess I'm also going to need to learn about reading an ohm meter.

Drat, more stuff to learn! More shop time!

Thank you,
Daryl
MN


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## raross61 (Jul 21, 2013)

Uglydog said:


> Found what is labeled a "thermal" in the Gisholt's electrical panel next to the magnetic switch. There are two thermals.
> One of them has little bubbles/blisters on the sides. Similar to what you would expect from paint that has gotten hot.
> I expect this is a problem.
> 
> ...



Daryl,

Here's what I know about this, the thermal is actually a wire wound resistor, they are rated by a chart from the heater manufacturer, if the amps get too high they heat up more than normal (hot!), and in the thermal disconnect there are various devices used to detect the heat and disconnect the power from the motor to protect it, (usually a bi-metal piece similar to a old car choke coil). So it has been my experience these thermals don't go bad very often, just like a wire wound resistor for it to fail, it would normally burn open and nothing would work!

Remember these heaters are matched to a exact, motor amp specs; IE Did anyone change the motor on this machine? and it is not the same amps, effiency, power factor? You said it just started doing this, so I assume you had it running before? Remember these thermals protect the motor from overload, is there anything mechanical going on here? Bearings, something binding etc. Remember the overload could be either be electrical or mechanical? Need to eliminate the mechanical just to be sure, if something happened to be too tight somewhere it may trip the thermal also.
Maybe I missed it, but I asked you once before what type of motor are we dealing with? With 2 thermals it sounds like a single phase motor? The three phase always have 3 heater’s in there, single phase, three phase of a static converter or?
　
Thanks Bob in Oregon


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## Uglydog (Jul 21, 2013)

raross61 said:


> Daryl,
> 
> Here's what I know about this, the thermal is actually a wire wound resistor, they are rated by a chart from the heater manufacturer, if the amps get too high they heat up more than normal (hot!), and in the thermal disconnect there are various devices used to detect the heat and disconnect the power from the motor to protect it, (usually a bi-metal piece similar to a old car choke coil). So it has been my experience these thermals don't go bad very often, just like a wire wound resistor for it to fail, it would normally burn open and nothing would work!
> 
> ...



Sorry that I missed your the motor question. I believe it's the factory motor 10hp 3ph, I can't see the spec plate based on the tight fit under the headstock of this 5000lb 1936 Turret Lathe. I picked up a 20hp rotary converter. A couple days before I first noticed it was cutting out, I had a short in the factory switch which blew a circuit breaker in the main panel. It's now repaired. Could that have done it?


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## raross61 (Jul 21, 2013)

Uglydog said:


> Sorry that I missed your the motor question. I believe it's the factory motor 10hp 3ph, I can't see the spec plate based on the tight fit under the headstock of this 5000lb 1936 Turret Lathe. I picked up a 20hp rotary converter. A couple days before I first noticed it was cutting out, I had a short in the factory switch which blew a circuit breaker in the main panel. It's now repaired. Could that have done it?



 Daryl,

That's great glad you got a rotary converter! The static one for you saw, will probably be fine, due to the fact that it is a lot lighter use than a lathe. Tha converter cutting out could have been the problem, depending on what was going on with the rotary converter, these 3 phase motors do not running on 2 legs, so if your contactors etc get carbon built up on them, and it looses one leg, it will almost always blow the line fuses or trip thermals, especially on start up! Might want to lock the power out, and inspect and clean the contactor, I use some diamond files, and some electric cleaner. CAUTION: Make sure the electric motor fumes are totally aired out of the contactor box before you turn it on!! I Watched a guy due that once, without it aired out, on a huge metal roll, at my buddies shop, there was machine oil in there, and it caught fire and burnt up 60% of the wiring in the box, as soon as it turned on and the contactor sparked! 
                                                     Bob in Oregon


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## Ulma Doctor (Jul 21, 2013)

Uglydog said:


> I picked up a 20hp rotary converter. A couple days before I first noticed it was cutting out, I had a short in the factory switch which blew a circuit breaker in the main panel. It's now repaired. Could that have done it?



Hi Uglydog,
have you tried to perform an amp draw test on the Gisholt??
have you taken a voltage reading from all 3 legs of the converters output?
is your 20 hp converter balanced?

it seems rather odd for your system to have only 2 thermal overloads, can anyone post a wiring diagram or schematic??

mike)


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## raross61 (Jul 21, 2013)

Ulma Doctor said:


> Hi Uglydog,
> have you tried to perform an amp draw test on the Gisholt??
> have you taken a voltage reading from all 3 legs of the converters output?
> is your 20 hp converter balanced?
> ...



Mike,

    I thought the same thing? Don't all three phase contactors, have 3 thermals? I also asked him if this was running for a while, and then quit? Or is this a new startup?

                                                        Bob in Oregon


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## Ulma Doctor (Jul 21, 2013)

raross61 said:


> Mike,
> 
> I thought the same thing? Don't all three phase contactors, have 3 thermals? I also asked him if this was running for a while, and then quit? Or is this a new startup?
> 
> Bob in Oregon



i can't say that all 3 phase overloads contain 3 heaters,
 but, i can say that i have never seen a heater type three phase overload without 3 heaters.


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## Uglydog (Jul 21, 2013)

Ulma Doctor said:


> i can't say that all 3 phase overloads contain 3 heaters,
> but, i can say that i have never seen a heater type three phase overload without 3 heaters.



Tomorrow I will take and post some pics of the Gisholts electrical panel. I'll be sure to show the thermals and the only electrical schematic I have. 
The electrical short was on the on/off for the Gisholt not the rotary.
Rotary was installed by an apprentice electrician friend, not by me.


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## rdhem2 (Jul 23, 2013)

You guys are fun!  Now I will show my age.  Thermals have only been required by CODE to be in each current carrying conductor to a motor since the 1968 National Electrical Code.  Before that the thinking was that the current flowing through the leg with no thermal was also being shared by one of the two other legs.  This is not always true such as when that leg goes to ground or has low impedance to ground.  Lots of older equipment only has two overloads on three motor leads.

You are correct in saying that all three legs should have thermal protection.

The heat from the heater melts a solder pot that allows a spring loaded spindle to rotate opening a set of contacts in the control circuit de-energizing the coil to the magnetic starter or tripping the latch mechanism in a manual starter.  Some brands of starters have the solder pot in the heater itself, (Square D), and some have the solder pot as a component of the starter overload block itself. (Cutler Hammer).  The advantage goes to the solder pot in the heater style.  This is because when the heater melts and the spindle spins, a minute amount of solder is usually lost.  Next time there is less solder to melt so it trips sooner.  Good for the motor, bad for you.  This is referred to as nuisance tripping.  By merely changing out a six dollar heater you have fixed the problem.  If you have the other type you may be able to repair the overload block but usually you will need to replace  the whole unit at a far greater cost.

WOW!  Do I get windy!


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## Uglydog (Jul 23, 2013)

rdhem2 said:


> You guys are fun!  Now I will show my age.  Thermals have only been required by CODE to be in each current carrying conductor to a motor since the 1968 National Electrical Code.  Before that the thinking was that the current flowing through the leg with no thermal was also being shared by one of the two other legs.  This is not always true such as when that leg goes to ground or has low impedance to ground.  Lots of older equipment only has two overloads on three motor leads.
> 
> You are correct in saying that all three legs should have thermal protection.
> 
> ...



Good information, thank you.

Please find the attached photos. Please note this is from a 1936 Gisholt with presumably the original 10hp motor and panel.
I pulled the blistered thermal for your viewing pleasure.

The last pics are of the inside of the motor from the Wells Bandsaw. Yep, Mud Wasp Nests. 3 of them. Motor was getting hot, very hot. Pulled it apart. Blew even more dust out. Lots of it and removed the 3 nests. Still very hot and smoking. The armature (proper term?) was notably rough. Didn't want more thermal problems! I took the entire motor in to be looked at by a local 3 phase motor guy.  

Suggestions for the Gisholt thermals?
Thank you,
Daryl
MN


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## Ulma Doctor (Jul 23, 2013)

Gotta love them mud wasps, they kept my south bend lathe motor from running:angry:

Daryl, the thermals are type N33 many manufacturers make them. but you can still get them from Allen Bradley, Graingers and
 McMaster Carr carry them too, try Ebay for giggles while you are at it!!!
here's a link that may explain some things about your type of heaters...

http://literature.rockwellautomation.com/idc/groups/literature/documents/td/815-td002_-en-p.pdf

i hope the info helps out!!
mike)


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## raross61 (Jul 23, 2013)

Daryl,

    Well that one picture, blows my theory on cleaning contacts, Man silver alloy? Had to be when they built stuff to last! Sounds like maybe the thermals are just weak, but that also comes back, to confirm that you should amp check each leg and see it they are pretty even!

                                                      Bob in Oregon


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## Ulma Doctor (Jul 23, 2013)

A N33 is kinda too light for a 10 hp motor that's only a little over 13 amps per leg for a size 2 or 15 amps on a size 3
i would go up to N38 ish.
 maybe N38 since only 2 legs are being thermally protected and your're gonna be pulling some amps on start up.
the N38 is still in the safe zone for your wiring under , being under 25 amps.


mike)


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## Uglydog (Jul 23, 2013)

Copy,
N38 thermals.
Scored some on Ebay. 

Check amp on each leg.....
Ah.... got an amp meter.... how do I check amp on each leg?
How do I set the meter?
Where do I connect/touch the probes?
Off the 3 fuses in the box going to the panel in the pics?
Where does the other probe connect/touch to?
Should the motor be Gisholt motor be running or just the Rotary?


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## raross61 (Jul 24, 2013)

Uglydog said:


> Copy,
> N38 thermals.
> Scored some on Ebay.
> 
> ...




Daryl,
As much iron as you are acquiring lately may I make a suggestion? You might be able to do it with a regular “Lead Type Meter” but it’s a little tricky, amps is like flow in hydraulics, so it always has to be measured in series only! If it hooks directly across the supply lines it will blow the protection fuses, if it has them, and maybe damage the meter! I would suggest you either borrow or buy a “clamp on AC Ammeter” The AC only ones are not a whole pile of money, home depot and lowes have them, maybe around $69, with them there is a small circle type clamp that opens up on the end and you just set the scale to ac amps, , and close the loop around each wire feeding the motor one at a time, and read the amps. In the contactors we have at work we test monthly, we leave a little extra wire in the panels so it is easy to put the clamp amp meter onto them. It really only takes maybe 20 seconds and tells you a lot!

The regular amp scales on a general purpose millimeters, usually only go to 10 amps, maybe 20, and if you read the instructions, it is only meant to be on there a very short amount of time, (duty cycle). So when your motor starts it will be way over the meter rating! They are designed more for like testing amps on stuff like, car stereos, cb’s, fog lites, and stuff like that.
Bob in Oregon


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## raross61 (Jul 24, 2013)

Daryl,
     This is a pdf from a high end clamp on meter on how its done, this is a pretty high $ meter, one from Lowes of Home Depot, will get these simple checks done for you, on your motor:


http://cp.literature.agilent.com/litweb/pdf/5990-5192EN.pdf


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## Uglydog (Jul 24, 2013)

Prices for clamp ons vary widely.
Like everything else, you likely get what you pay for.
Would either of these work?

http://www.harborfreight.com/digital-clamp-on-multimeter-95652.html

http://www.harborfreight.com/digital-clamp-meter-96308.html


Thank you all for your patience.
Daryl
MN


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## raross61 (Jul 24, 2013)

Uglydog said:


> Prices for clamp ons vary widely.
> Like everything else, you likely get what you pay for.
> Would either of these work?
> 
> ...



Daryl,

Yes I say you get what you pay for!, Keep in mind here you are making a go / no go decision, on a 10 hp 3 phase motor, this is a pretty expensive item!, plus all the labor to remove and install it, The HF Electrical stuff can go either way good, or bad depending on, soldering, production tolerances, + a lot more, etc! I would opt for a little better item, but that’s also me. Lets look at it this way if you get a Greenlee, or Amprobe amp clamp, it will out live you and me, and you can pass it on to your kids. Nothing wrong here with being thrifty, that is why I buy everything online! Where I live in Portland, Oregon a small cheap store front, runs about $5000 a month, which is passed on to me, NOT! I don't care if I buy Greenlee,Amprobe, or any other item, in South Dakota, or another state, as long as it is the same P/N! I would LOVE to buy local, but if all I am doing is supporting a corrupt, Oregon Government I will NOT! So if you really want a deal on a clamp on meter, figure out the P/N you want, and Google it for the best price! The downside is you you have to wait, a little for shipping it to you!

Hope this helps Bob in Oregon


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## Uglydog (Jul 24, 2013)

Looks like this Amprobe should do the job?

http://www.amazon.com/Amprobe-ACD-6...&sr=8-2&keywords=amprobe+clamp+on+multi+meter


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## Ulma Doctor (Jul 24, 2013)

Uglydog said:


> Copy,
> N38 thermals.
> Scored some on Ebay.
> A) Nice, the N38 will give protection but won't cut out so quickly!
> ...


A) i would test the RPC solo at first to get a baseline. then after completing testing , i'd fire up the lathe and perform the testing again on both the RPC and the 
lathe.

I know it's a little confusing sometimes, let me know if this makes sense, we don't want to get you zapped!!!
mike)

- - - Updated - - -



Uglydog said:


> Prices for clamp ons vary widely.
> Like everything else, you likely get what you pay for.
> Would either of these work?
> 
> ...



Yes, Daryl they would work and are inexpensive. were' just looking for an approximation of amps anyway...
mike

- - - Updated - - -



Uglydog said:


> Looks like this Amprobe should do the job?
> 
> http://www.amazon.com/Amprobe-ACD-6...&sr=8-2&keywords=amprobe+clamp+on+multi+meter



Yep Daryl, that's a good one too.
Graingers has a Fluke meter inexpensively that has an amp fork and probes as well, they are right around $85
if you want to get into something a little heavier duty, but it is not necessary to spend a lot of money to get you tested out.
mike


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## Uglydog (Jul 24, 2013)

I ordered a clamp on multi meter.
I also ordered new in shelf worn boxes N33 and N38 for next to nothing on Ebay.
Both are enroute.
Please anticipate that I may attempt to provoke you into coaching me further when they arrive. 

Thank you,
Daryl
MN


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## Ulma Doctor (Jul 24, 2013)

Uglydog said:


> I ordered a clamp on multi meter.
> I also ordered new in shelf worn boxes N33 and N38 for next to nothing on Ebay.
> Both are enroute.
> Please anticipate that I may attempt to provoke you into coaching me further when they arrive.
> ...



Good score!!
 those heaters are going out of fashion, but they are reliable until they shut down a few times.
a couple extras if they are cheap wouldn't hurt, most hardware stores,... etc. don't carry them. 

make sure you replace both heaters with the same number when you do it, don't use 1 N33 and 1 N38 on the machine!!

I'll be here if you need more coaching anytime, Daryl!!
no worries!!
mike)


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## raross61 (Jul 25, 2013)

Uglydog said:


> Looks like this Amprobe should do the job?
> 
> http://www.amazon.com/Amprobe-ACD-6...&sr=8-2&keywords=amprobe+clamp+on+multi+meter



Daryl,

     I know it sounds like I was trying to spend your money, but I am glad you made this choice! Anything from HF, that is electrical I figure it is maybe good for one , or maybe 2 uses! Let me caution you, I can say no matter which ampmeter you get, be pretty careful about dropping it! The core that opens up, to sense the current field can be pretty fragile, other than that I think once you get this, you will use it for all kinds of stuff at your place! Even on single phase stuff!

                                   Take Care Bob in Oregon


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## rdhem2 (Jul 25, 2013)

Gents;  The "N" series AB heater is just the heater portion only.  If you step up you may also use the "W" series heater which has the heater and aforementioned solder spindle included.  To use  the "W" series remove the existing solder spindle by removing the two small screws under the heater on the overload block.  The spindle is spring loaded so will jump out at you when you loosen the second screw.  Relax, this is normal!  Throw the old solder pot and two screws away and insert the new heater with the two original large screws.  Now push the reset button/bar and the unit will be good to go.

Both series of heaters are wound with the same size nichrome wire so the numbers on the heater remain the same.  Check the motor name plate, the consult the heater chart and get the heater that as close as possible matches the amp draw of the motor.  Do not oversize.  Heaters are already sized to allow a twenty five percent overload without tripping.  Remember this is a slow operation.  The motor must remain in an overload condition for a period of time before tripping.  This allows time for the heat to build up in the motor and temporary overload conditions to cure themselves.  The fuses/breaker ahead of the starter are there for the instantaneous disruption of power should a serious overload or short circuit or ground take place.  A oversized heater will allow the motor to cook and basically provides no protection at all.  Insulation break down caused by excessive heat is what this is all about.  The reason motors burn out.

By the way, the starter you have is indeed an oldie but a goodie.  Should anything happen to it you may have trouble getting repair parts.  I would plan on scrapping it when the time comes and replacing with something produced in the 20th or 21st century.  Just a thought.

HTH


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## raross61 (Jul 26, 2013)

rdhem2 said:


> Gents; The "N" series AB heater is just the heater portion only. If you step up you may also use the "W" series heater which has the heater and aforementioned solder spindle included. To use the "W" series remove the existing solder spindle by removing the two small screws under the heater on the overload block. The spindle is spring loaded so will jump out at you when you loosen the second screw. Relax, this is normal! Throw the old solder pot and two screws away and insert the new heater with the two original large screws. Now push the reset button/bar and the unit will be good to go.
> 
> Both series of heaters are wound with the same size nichrome wire so the numbers on the heater remain the same. Check the motor name plate, the consult the heater chart and get the heater that as close as possible matches the amp draw of the motor. Do not oversize. Heaters are already sized to allow a twenty five percent overload without tripping. Remember this is a slow operation. The motor must remain in an overload condition for a period of time before tripping. This allows time for the heat to build up in the motor and temporary overload conditions to cure themselves. The fuses/breaker ahead of the starter are there for the instantaneous disruption of power should a serious overload or short circuit or ground take place. A oversized heater will allow the motor to cook and basically provides no protection at all. Insulation break down caused by excessive heat is what this is all about. The reason motors burn out.
> 
> ...



Just wanted to personally say Thanks, for the heads up on the two heater style overload system! Never came across one of these, before! I do see where it would work perfect, in the normal 3 phase delta setup, but like you said when one leg grounds, to the case, and especially the leg with no heater! Now that's another story! IE=BAD

Take Care Bob in Oregon


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## raross61 (Jul 30, 2013)

Uglydog said:


> I ordered a clamp on multi meter.
> I also ordered new in shelf worn boxes N33 and N38 for next to nothing on Ebay.
> Both are enroute.
> Please anticipate that I may attempt to provoke you into coaching me further when they arrive.
> ...



Hi Daryl,

     Just wondering did you get your new meter yet? I was just dying to know, if you got your meter? And is the Gisholt going again?

                                            Bob in Oregon


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## Uglydog (Jul 30, 2013)

raross61 said:


> Hi Daryl,
> 
> Just wondering did you get your new meter yet? I was just dying to know, if you got your meter? And is the Gisholt going again?
> 
> Bob in Oregon



Thanks for following up!
The Amprobe ACD-14 clamp-on arrived today (7/30).
I'll do some reading tonight, with a hope of growing some confidence on how to use it.
It's on my list of things I want to complete before we leave to visit TOAG in Ohio.
Likely I'll start a new thread so that anyone searching for how to balance 3phase legs can find it.

Whadaya think? Is that a good idea?


Daryl
MN


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## Uglydog (Jul 31, 2013)

Disclaimer: only a licensed electrician should do this!
EVER!!

Results: 
Test #1
Avg .0404, Max Deviation .2696
Line A / Leg 1 .043
Line B / Leg 3 .31
Line C / Leg 2 .011

Test #2
Avg .0516, Max Deviation .0056
Line A / Leg 3 .0216
Line B / Leg 2 .079 
Line C / Leg 1 .023

Test #3
Avg .0656, Max Deviation .0106
Line A / Leg 2 .0164
Line B / Leg 1 .0106
Line C / Leg 3 .0056

Looks like Power Source Line C is the problem and not the motor.
Most likely the used (CL) Rotary Phase Converter. 
Hmmmm.
Do in line fuses (not circuit breakers) get weak? Or are they always on/off, work don't work?
Fortunately, the manufacture of the Rotary is a local small electrical company with a good reputation. However, it won't be under any kind of warranty. 
The current configuration (Test #1) has the worst results!
Think I'll wire her in the Test #2 configuration with a Thermal N33 and see what happens.

Any observations or corrections?
I really don't know what I'm doing and sincerely appreciate all of your input and feedback!!

Daryl
MN


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## rdhem2 (Jul 31, 2013)

Are we assuming the motor is running?  Seems like not, but than you should have no reading what so ever.  Amprobes usually have a six amp scale.  Turn down to that and see what you get.  Usually a motor idling along with no load will draw from about 1/3 to 1/2 the name plate rating.  If you mentioned the full load nameplate rating I missed it.  Just clamp the jaws around the wire going to one of the motor leads.  If the reading is small wrap the wire around the jaw several times then divide the reading by the number of wraps.

Unless you are experiencing nuisance tripping of the overloads or the readings are really unbalanced, like 30 to 40% or more phase to phase don't worry about it. You are going to get goofy readings anyway with that phase doohickey thing you are using trying to invent the third leg.

Good luck, keep us posted.


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## Uglydog (Aug 24, 2013)

Finally got back out to the shop!
Ran the Gisholt for 3 hours straight boring 1/8" black pipe... really slow.
Needed a sleeve. Wish I'd have had some different scrap. 
No problems with the Gisholt whatsoever!
Really hot ambient temperature, and all the houses have their ACs on. Just in case it might have been power company issue.  

Looks like changing some wires around and seeking improved balance made all the difference. 

Thank you all for being patient with me as I expand my marginal electrical knowledge!!!

Daryl
MN


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## Ulma Doctor (Aug 24, 2013)

Hey Daryl, i'm glad to here everything's running well...
If you are interested i can help you get your RPC easily within 5% balance if you are so inclined.
The third leg is generated by induction, there really is no magic happening inside your RPC.

Contrary to popular belief it is quite easy to balance even a 25 hp RPC, if you know a couple things before you start.

If you are interested send me a PM, i'll get you dialed right in.
i'm happy to help out anytime...

mike)


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