Thread: Rotary Phase Converter Designs and Plans

Howdy,
I mght be getting a 2 post lift with 2 2.5 hp 3 phase motors on it. With my research it is defined as a "hard start" and they reccommend a 11hp or bigger idler.
Would you agree?
Second i was planning on building a poney start design off of:
Pony-Start Rotary Phase Converter
Design. (sorry i have read soo much i forgot whos responcilbe for this one). Any issues with putting in a times relay and a contactor to replace S1?
How important is voltage of idler motor vs the motors on the lift?
What values should i consider for my contactors / fusing / and breakers?
Thanks
Ed O
P.S. If anyone in central wi has a smoking deal on a motor or any other used parts let me know.

If both motors are starting at the same time, I would say yes to the recommended size of the idler. Probably wont find an 11 HP motor in your local salvage yard but 10 or 15 are both pretty common.

If you were going to just run the lift all the way from bottom (unloaded) to the top there would little start up issue, however we all know the height is never quite right the first time.

As for the generated or wild leg voltage, for straight loads without fancy electronic controls, you should have no problem with the generated leg.

All that said, is there any other option? I have seen folks use a phase converter to run their temporary loads such as air compressors but compressors often run for several minutes at a time. With an electric hoist we are talking about 30-60 seconds. lots of starts and stops therefore the contactors and relays would need to be a bit more robust.

Just my opinion...

Thanks,
Would you think a 10hp would do the job? I was thinking either a 15 hp idler or a 5 and 7 hp set of idlers.
MY other options are replace the 2 motors with single phase ones. Impossibile to find used matched motors and not cost effective to buy new. Also then i have a complete rewiring and size and belting issue. OR I could just adbandon this lift and try to find a single phase or hydralic one.
Would you reccommend not powering a lift with a rpc? Or for all my straight through loads going to 50 amp contactors? IF i build one i can also get the drill press i allways wanted and a small mill.
I was also thinking i dont need all 3 sets of phase correction caps, if i read right it sounds like i wont really need any?
Thanks
Ed

Someone more qualified may back me up on this one, but if you chose to use the lift with 2 motors, I would think the 10HP idler would handle the job.

But first; what kind of hoist is this? if it's a used system that you have found that is inexpensive it's one thing, but if you are shopping for a new system; I would look harder at a single-phase version. I have never seen a hoist that uses two electric motors so I'm a bit curious.

As for the run capacitors, I've heard they also provide some help with startup of the attached motors so it may be beneficial to use them. two idler motors may make things more complex than you really want.

If you are wanting future scalability for your home shop, a 10HP idler will likely provide plenty of that! Most mills, drills, lathes, etc that home shops use are something less than 3-5 HP.

Its a hh-lift model 2m. It is a rotery lift that has a screw on each side powered by a motor for each side. Each motor is a ASEA brand but i dont have all the specifics right now. Cost would be a barter, i d some work for a friend and get a lift out of it.
Ed

simular to this one
http://www.interschola.com/displayit...items_id=23879

I've read almost all the posts and still can't figure out how to wire this thing up. I purchased this 15 hp rpc used several years ago am just now at the point of needing it. I'm hoping someone can help.
1) I've installed a sub panel with a 90 amp breaker
2) I've installed a 3 phase panel with a 60 amp breaker
I'm hoping I can include the pictures - (I don't do computers very well either)

Questions-
1) Does the phase converter "look" OK?
2) It looks to me like the single phase, the idler motor and the three phase circuit/motor were all wire through the terminal block. If that is so, which side of the terminal block should each set of wires go to?
3) what size wire from single phase to the converter? Converter to the idler? converter to 3 phase breaker panel? 3 phase to 10 hp lathe?
4) I don't like the way the caps wires are "stuffed" into the terminal block. is this a problem?
5) I have a magnetic controller (used). Should I install it? How???
Sorry for the sophomoric questions, I'm way in over my head. Thaks for any and all help. Norm

Your photos don't really do much for me to understand exactly how you have it wired.

Main Relay applies single phase power to two of the motor leads and the start caps should be set to connect from one input leg directly to the third motor lead. The run caps will be connected between both hot legs and the third leg at a minimum. The terminal block is a great way to clean up the configuration and allows you to maintain a better connection between the motor and the bank(s) of capacitors. If you'll reference previous posts in this thread along with a couple others You'll see there are many ways to utilise terminal blocks to facilitate a cleaner and safer install. The start cap circuits need to be well designed to safely start a 15HP idler motor.

My 15HP converter has 2ga copper coming into the main relay/starter and 4ga from the relay to the motor. I then have 4ga coming from the converter to a junction block that is 20 feet away. The size of conductors can vary significantly by the length and size of the load. Mine is probably overkill but you can reference several online resources or an "Ugly's" book to determine the exact size of conductors you need. I'm assuming the 10HP motor you have is hard starting so I would probably lean on the heavy side for conductor size despite the cost of copper.

Is that a timer for the start cap's in the picture? If so, how will it work in conjunction with the start switch?

I guess I was getting ahead of myself. I was steaming ahead on a RFC before checking on how my lathe was wired. Well, it's a 10hp 440 machine. The motor can be wired for 220 but there is the other stuff. The lathe has it's own contactor and overload protection, but for 440. I've been looking though a Factory Mation catalog and it looks to my untrained eye that the contactor and the thurmal relays could be replaced with units compatable with 220. However, I'm sure that it isn't that simple. Could somebody set me straight. Here are some pictures of electrical compartment on the back of the lathe. Thank you very much for any help. Norm

And now I've found the wiring schematic. I seem to be going about this backwards. Norm

Far Far easier to get a transformer as suggested in your thread here in post #2

440 lathe to 220??

Then you can build a 15 HP RPC that puts out 240 and the lathe can run on the higher volts (440/460/480) and you won't have to mess with all its gizmos.

J.O.

any suggestion as to Size and make of transformer? where to get, etc.?

I suggested 15 KVA and here is one on Ebay. New they are more money.

SQUARE D TRANSFORMER 15KVA 3 PHASE # 15T6H | eBay

J.O.

That looks like a good price. Seems hard to find a low price if you need it. lol

Ok
I Have a motor and i am ready to start my looking for my final componets to build my rpc. Its going to be a 15 hp 3450rpm pony start with a 1/2HP pony.
I have a few questions. I will post a pic of my modified design from Jim Wilson. I added a timer relay and fuses. I will have to figure out wire sizes based on the fuse values. For K3 i will use a 15hp motor starter with thermal protection
Question 1 Are my fuse locations ok? what values should i use?
Question 2 What size breaker should i have on the 220 input?
Question 3 are my contactor sizes ok?
Question 4 What size 3 phase breaker should i output through?
Question 5 Do i need to balance my voltages with caps being i am just running the motors on a lift?
Question 6 Do i need to pony to get the main up to full speed or is half speed ok (lovejoy vs pulleys).
Thanks
I will try to attach the pic if i can.
Ed Owens

Originally Posted by fortytwo

Ok
I Have a motor and i am ready to start my looking for my final componets to build my rpc. Its going to be a 15 hp 3450rpm pony start with a 1/2HP pony.
I have a few questions. I will post a pic of my modified design from Jim Wilson. I added a timer relay and fuses. I will have to figure out wire sizes based on the fuse values. For K3 i will use a 15hp motor starter with thermal protection
Question 1 Are my fuse locations ok? what values should i use?
Question 2 What size breaker should i have on the 220 input?
Question 3 are my contactor sizes ok?
Question 4 What size 3 phase breaker should i output through?
Question 5 Do i need to balance my voltages with caps being i am just running the motors on a lift?
Question 6 Do i need to pony to get the main up to full speed or is half speed ok (lovejoy vs pulleys).
Thanks
I will try to attach the pic if i can.
Ed Owens

What's the FLA on the motor? That will determine the breaker ,wire etc. The disconnect will have an amp rating and a HP motor starting chart. I can't pony start my 10 hp so I use a gas motor and it fires right up. The 15 hp motor will probably require 2x the motor FLA to start, if you can't get it spinning by a pony motor.

The motor is a Baldor jmm3314t
I believe from reading the spec sheet the fla is about 40 amps
http://www.motoragents.com/pdf/Baldor/JMM3314T.pdf
this is the spec sheet for it.
Thanks
Any help is greatly appreciated.
Ed

Hello folks

is the use of a 3 ph vfd possible to control a 120 v-single ph ac spindle motor, other option is an encoder,already -in place. I have no experience controling a single phase ac spindle motor (newbee) this is a compact 5 pc lathe I am upgradeing to all new motion electronics K-l 4030 controlers , C11G BOB with the usuall power suplies ,so after all the biggest thing , descision is to just swap the cogged belt drives or build motor mounts to direct couple the motors & eliminate the belt drives ? opinions?, sugestions welcome. also any one have a good source for a vfd suitable to control the ac 120 v motor that currently has the oem pulleys in place. Very limited speeds ...


all ideas welcome
TIA

Don

i just bought a mill and i got a phase a matic converter and it does not use a motor in the set up what is the advantage and disadvantage of motor or not

Originally Posted by bartech

i just bought a mill and i got a phase a matic converter and it does not use a motor in the set up what is the advantage and disadvantage of motor or not

Which one Does it look like? I can't post a picture

Rotary Phase Converter, Static Phase Converter, and CNC Phase Converters - Phase-A-Matic

OK, I have read the thread, and still I am challenged! I see some pics with one motor, which seems to produce 3 phase for equipment. I see pics with two motors. The RPC's with two motors is what I put together, thinking it would start the 3 HP, 3 phase mill I have, it does not. I am missing the Caps and do not understand what they do? I have printed off 3 plans from this thread and will set about reading and hopefully learning.
This unit below does not start the mill I have.
http://i674.photobucket.com/albums/v...f/DSCN0684.jpg
It is obvious I do not understand this?