Mill is 3-phase 440v, I have 1-phase 220v - What kind of options do I have?

Ron

To the best of my knowledge, I have never seen an RPC that could increase the voltage. IF you feed it with 220V single phase, you will get 220 V 3 phase output.

The next step is to add a 3 phase 220V to 440V step-up transformer.

Now if you look at the wiring diagram for a RPC, you will notice that the Black and Red wires go from the input breaker and continue, unbroken throughout the entire RPC. So even if the generator motor is not turning, there is still 220V single phase being applied to two legs of the three phase motors etc. The transformer needs to be protected from ever being energized in this way so a magnetic contactor (called in this instance as a Timing Line Contactor), large enough to handle the current load is placed between to output of the RPC and the input of the transformer and wired so that it will only energize if there is voltage present in the third leg.

Personally I prefer to size the TLC Contactor to handle the complete output of the RPC, that way, no motor on the circuit will ever see single phase as voltage will only ever pass beyond the TLC if the 3 phases are all present.

Now going the 220-440V transformer route will increase the cost of your installation by the cost of the transformer and possibly a distribution centre for the 440V. If you are only going to ever run the one machine, then you can wire it directly into the output of the transformer, but you will need to make sure the input of the transformer is properly fused. If you may ever get other machines that could run on 440V then look into a 3 phase load centre and breakers so that you can divide the output of the 440V to each machine.

Now as to your other option, rewiring the mill to 220V. That may be possible, but you will have to look at a few things. The motors have to be dual voltage and you have to rewire each motor to suit the 220V (some motors like 2 speed motors are only single voltage). More importantly is the coils in the contactors and any control transformers and any lights. If the coils on the magnetic contactors are 440V, they will need to be replaced with 220V coils. Many times though, the contactors may be low voltage, say 24V (this keeps high voltages away from the push button switches that us humans will be pushing) and there will be a transformer to step the input voltage down to that voltage. Once you have determined how many changes need to be done, you may find it easier to rewire to 220V or you may find that going plug and play, IE step-up transformer off the RPC will be better.

Walter
 
starlight_tools said:
Ron

To the best of my knowledge, I have never seen an RPC that could increase the voltage. IF you feed it with 220V single phase, you will get 220 V 3 phase output.

The next step is to add a 3 phase 220V to 440V step-up transformer.

Now if you look at the wiring diagram for a RPC, you will notice that the Black and Red wires go from the input breaker and continue, unbroken throughout the entire RPC. So even if the generator motor is not turning, there is still 220V single phase being applied to two legs of the three phase motors etc. The transformer needs to be protected from ever being energized in this way so a magnetic contactor (called in this instance as a Timing Line Contactor), large enough to handle the current load is placed between to output of the RPC and the input of the transformer and wired so that it will only energize if there is voltage present in the third leg.

Personally I prefer to size the TLC Contactor to handle the complete output of the RPC, that way, no motor on the circuit will ever see single phase as voltage will only ever pass beyond the TLC if the 3 phases are all present.

Now going the 220-440V transformer route will increase the cost of your installation by the cost of the transformer and possibly a distribution centre for the 440V. If you are only going to ever run the one machine, then you can wire it directly into the output of the transformer, but you will need to make sure the input of the transformer is properly fused. If you may ever get other machines that could run on 440V then look into a 3 phase load centre and breakers so that you can divide the output of the 440V to each machine.

Now as to your other option, rewiring the mill to 220V. That may be possible, but you will have to look at a few things. The motors have to be dual voltage and you have to rewire each motor to suit the 220V (some motors like 2 speed motors are only single voltage). More importantly is the coils in the contactors and any control transformers and any lights. If the coils on the magnetic contactors are 440V, they will need to be replaced with 220V coils. Many times though, the contactors may be low voltage, say 24V (this keeps high voltages away from the push button switches that us humans will be pushing) and there will be a transformer to step the input voltage down to that voltage. Once you have determined how many changes need to be done, you may find it easier to rewire to 220V or you may find that going plug and play, IE step-up transformer off the RPC will be better.

Walter
Click to expand...

Thanks Walter. After I posted and thought about it some, the bit about an RPC with 220 input to 440 out, I knew that I hadn't gotten that right. With your help, I'm thinking that the step-up transformer would be the way to go but I'm really interested in the TLC. I've been trying to read what I can on RPCs but have found little/no mention of using a TLC. Do you have a good source for those? I'm all about protecting my gear as best I can.

So, as a re-cap, I am wanting an RPC that will take single-phase 220v and output 3-phase 220v (or 230v as the standard may be now) then use a step-up transformer to give me the 440v (460v) 3-phase the mill wants to see.

Now, the mill has a 2hp motor and a 3hp motor but they will not be in use at the same time. I know that the costs will increase as the hp rating does. I would assume that due to the step transformer I would need to provide more Kva to utilize the full power of the motors so would that automatically throw me in the 6hp and up range? Then should I also build more into the system for future use, say 10 or 15hp?

Where would you guys source your components for this? I've seen a couple commercial sites with offerings but they aren't as comprehensive as needed to give a road map for someone with no experience. I know some of you would build your own systems using salvaged materials, motors, etc. but there seems to be a lack of such in this area as far as I'm aware of. In other words I may need to order/ship in anything I needed. By the time I do that would it just make more sense to buy one commercially built? (Hoo-boy! There's that "sense" thing. The wife would be so proud. :eek: :lmao::lmao:)

Thanks again,

-Ron
 
Ron

We are a dealer for PhaseMAXX RPC's.

their website is http://www.electram.com

I have the engineer there build a system based on the clients needs and specs.

When I had mine built it was before I realized the importance of the TLC, since then I have had them built into the enclosure for the unit.

These units are CSA/UL rated for use anywhere in Canada or the US and are made in Edmonton, Alberta.

The generator is not just a 3 phase motor with its shaft chopped off, they are specially designed with a high flux core to give better performance as a RPC.

There are a few add-on features that are nice to get,

first they have a soft start unit that starts in steps and avoids browning out the neighbourhood.

second, VLS, Voltage Level System, a voltage regulator, this is for when you will be running both smaller and larger motors off the same system.

thirdly the TLC which protects motors and transformers from being single phased.

I will email you a PM of other details

Walter
 
Thanks Walter, I'll go over it in detail. I expect it will be a great help.

-Ron
 
Ron, now that you have the mill on site, have you looked at the labels on the two motors? I'm itching to get my mill home so I can check whether I can reconnect the motor for 220V. Since the junction box and label are deep inside the column, I'll have to take the motor out to find out if I can use it. Here's hoping.:bitingnails:
 
Yes, I did find out about the motors. According to their tags both of them can be wired for 220v (3-phase) so that may take some of the complexity out of the solution. I guess it also gives me another question about the motors, is there anything else that needs to be changed other than the wiring? Is it just that simple to follow the diagram on the motor and it's ready to plug in to a 220v 3-phase source? If it is I can fore go a transformer to kick the voltage up to 440v and save some money to spend on more tooling. :biggrin:

I'll take a pic of the motor plate tomorrow for better reference.

Thanks,

-Ron
 
starlight_tools said:
Ron

Now as to your other option, rewiring the mill to 220V. That may be possible, but you will have to look at a few things. The motors have to be dual voltage and you have to rewire each motor to suit the 220V (some motors like 2 speed motors are only single voltage). More importantly is the coils in the contactors and any control transformers and any lights. If the coils on the magnetic contactors are 440V, they will need to be replaced with 220V coils. Many times though, the contactors may be low voltage, say 24V (this keeps high voltages away from the push button switches that us humans will be pushing) and there will be a transformer to step the input voltage down to that voltage. Once you have determined how many changes need to be done, you may find it easier to rewire to 220V or you may find that going plug and play, IE step-up transformer off the RPC will be better.

Walter
Click to expand...

Ron we already discussed what else might need to be changed when changing from 440V to 200V!

The other item to look at is the wire sizing. Motors draw a certain amount of watts to run. Watts is Voltage times current. Wires are sized to carry a certain amount of current at the specified voltage. If we half the voltage, we will double the current for the same number of watts. This means that the wires must be heavy enough to handle the extra current. Now in most cases, the manufacturer will use wiring that is ok for both when wiring up the machine, but that is not to say that the wiring from the machine to the wall, or plug is heavy enough. Basicly, 14 gauge wire is good for up to 15 Amps, 12 Gauge up to 20 Amps 10 Guage up to 30 Amps and 8 Guage up to 40 Amps.

Now at 3 HP you would be hard pressed to get anywhere near 15 Amps in motor draw even at 220V so you will probably be OK.

It is the contactor coils and transformers that you need to check the most.

Walter
 
Thanks Walter, I did read that through and understood it so I don't mean to come across as ignoring your input, I have found it very valuable. Sometimes my phrasing leaves a bit to be desired though. (Believe it or not I actually went to college as an electronics engineer but that's been 30 years ago and I never paid much attention to power systems like this or motor design.) The reason I didn't bring up the wiring is that that is easily checked, a pain to change, but easy to verify. As my panel was wired to code and there is nothing smaller than a 15a breaker I figure I should be okay but I will check. I also have confirmation that my motors can be re-wired for 220v +- and there are no lights to worry about. Here are pics of the two motor plates...


The power feeds and DRO (which I may be replacing anyway as it's fubar) appear to run off of single-phase 110v so wouldn't be an issue either. By your description that would leave, "coils in the contactors" as a possible issue. I would think that there would be a warning of some kind along with the alternate wiring diagram if that were the case but that may be assuming too much. :p :) So far my searching hasn't pulled up much technical information on these motors and one of the reasons I'm looking for additional input. I like to keep things as simple as possible as well as keep the expenditures down to a minimum. (Again, my wife would be so proud! :rolleyes::biggrin:)

If the contactor coils are an issue how does one go about determining that? Sans that information it would appear that I can get away with an RPC and a TLC (as I understand it anyway).

Thanks,

-Ron
 
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Ron

The contactor coils are the coils which apply magnetism and "close" the magnetic switches (think very big relay). For any motor rated higher than about 1-1/2 HP they have to (should) be run on a magnetic switch. These switches will be located in an electrical control panel, probably the one that is mounted on the side of the base column. The on - off switches will energize the coils which will pull in the main contacts, and will keep them energized until either the stop switch is pushed, an over current is detected or power goes out from the machine. This will demagnetize the coil and allow the contacts to seperate, stopping the motor.

You will need to check out these coil voltages before you go any further. Check the over current protectors as well, they are to be set for the rated current of the motor and they will have to be set to twice what they are now, if they are set correctly now that is. Also, look far any signs of transformers in there. It could be that you have a transformer that has multiple input taps, 208/230/460 and one or more output taps. If the mill has only one power cord to attach to the wall, then probable that there is a transformer to feed the power feeds and the DRO. If the DRO was an add-On, it may have it's own separate power cord and plug.

It is possible that even the contactor coils are 110V and that it is all being fed off a transformer. They could also be 24 V.

Ron, hopefully I am not being to persnikety, but I do not want you or anyone else to get hurt by assuming me that you know better. SO, I tend to be more cautious when giving advise over the net like this, and try to think of where all the snakes could be hidden.

Walter
 
{A few missing posts...}

Thanks again Walter your input is appreciated very much. I continue to ask questions to get different views and to make sure I understand what I'm doing (tough one there :p) so that both my equipment and I are safe.

I was able to take a couple of pictures that may help show just what I have to work with:



A) Four-pronged (3-phase) plug
B) Cord attached to "A" going in to fuse box
C) to horizontal motor
D) to vertical motor
E) "to" and "from" switch between two motors




Contents of fuse box



A) 3-prong (single-phase 220v(?) plug)
B) cord from "A" into first out let box w/ 110v type sockets
C) cord from first outlet box to second outlet box

As you can see the power is delivered from two different sources to two separate systems. The outlet boxes are completely independent of the power for the mill's motors.
For the mill's motors, there isn't much there. Just a 3-phase fuse box.

Have I missed anything?

Thanks,

-Ron
 
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