HELP!!! 460 volt machine...what to do???

[GBeaman]

Hi everyone,

I just recently purchased a bostomatic 312 vertical cnc mill, built a shop brought the machine home and hooked up my 230 volt 3 phase homemade converter and found that the machine is a 460 volt machine. I am located near Austin, TX and the only bostomatic service folks are in Mass. I guess I
face paying air fare for an expert to do a voltage conversion totaling $3-4K or using a step up transformer to get the machine going. It has not run in several years so I am not sure of its running condition. Otherwise good condition with about 11K hours on it. Should I fork over the money to have this guy come down or do a conversion or scrap the money pit and move to something like a hurco. What do you guys think? I posted before with one response that didn't help. Hoping to find some action. Thanks Guys,
-Greg Beaman

[Al_The_Man]

What you should do is find out what is presently fed 460v, Any three phase motors can usually be changed to 220, the wire size and overloads would need to be checked to take the higher current.
The control transformer is probabally going to be single phase to 120v, check if there is a 220 v primary tap or change the txr to 220/120.
Spindle and servo drives are often 220 and have been transformed down, so you may be able to eliminate the intermediate transformer for these.
You really need the electrical power prints to make in informed decision. But often it can be a relatively cheap route.
Al.

[GBeaman]

Thanks Al,

I think you are right. I spent $1000 on the machine and would really like to get it going cheap. I don't have manuals for it, but I am making a real effort to uncover them. I found the main transformer you are referring to. It has a label that indicates it can be wired either with 460 or 230 input with 230 output. So I need to figure out how to rewire it to begin with. I think all of the drive motors, spindle, hydraulic pump and coolant pump are 230 volts, so...no need to change them. I am not really sure what is 460 volts if all of the other components listed above run 230. Someone mentioned contactors and overloads and possibly banding. I am not real sure what the banding is other then to guess it would be the braided ground type straps. I think that wouldn't be a huge concern and the overloads should be under rated so they should trip before harming any components correct? If so then I could replace the ones that tripped and caused trouble. The control input is 110V I believe. If I could isolate it I could wire it single phase from the house input...Correct? That would save running my phase converter while I programmed the part. Let me know what this sounds like.... I know babbling of an uninformed amature. Thanks.
-Greg Beaman

[Al_The_Man]

You may or may not be OK with wire gauge to motors etc, it depends if they were wired tight to size, the overloads can be turned up, if adjustable but may not reach high enough desired current.
I would check the 110v as it is common to set up a local grounded neutral when an isolated control transformer is used, Which I would stick to if possible, even if this means a new 1PH 220/110v trfmr, this makes for more of a self contained system.
What you do is wire this to the main 220 volt legs, if it is a rotary PH Conv., (never use the artificial phase for this). This would mean it could be on when the RPC is not running.
I would expect the Hyd. pump and Coolant to be presently connected for 460?
But they usually can be reconnected for 220.
Al.

[Bill Clark]

If all the power for the machine is coming from the secondary of the xformer the all you have to do is connect your supply to the 230 volt primary leads of the xformer.

[GBeaman]

I did a further investigation on voltages to the different motors. The spindle only says 230 volts on its i.d. tag so I assume that it is wired 230 volts. The hydraulics motor says 230/460 on the tag so I bet it is wired 460 and will need to be rewired to the 230 configuration. The coolant pump is the same, so I bet it is 460 too. The spindle chiller is 110 and I believe I located the control power input wires. I guess I will need to check the wire gauge to the two above mentioned motors and make sure that it is adequate for the amperages they draw. Do you concur about running a 460motor and overload setup should keep the motor protected as it would be like having a 10 amp braker where the max draw would need a 20. I should be safe to at least try to turn these items on without melting something down because the overload should trip. Thank you guys so much. I can see the light at the end of the tunnel and it isn't an oncoming train, or a $4K repair bill on a $1K to even get started. To clarify I have home made rotary phase converter. It is a 7.5 hp motor and is balanced and started with capacitors.

[GBeaman]

I did a further investigation on voltages to the different motors. The spindle only says 230 volts on its i.d. tag so I assume that it is wired 230 volts. The hydraulics motor says 230/460 on the tag so I bet it is wired 460 and will need to be rewired to the 230 configuration. The coolant pump is the same, so I bet it is 460 too. The spindle chiller is 110 and I believe I located the control power input wires. I guess I will need to check the wire gauge to the two above mentioned motors and make sure that it is adequate for the amperages they draw. Do you concur about running a 460motor and overload setup should keep the motor protected as it would be like having a 10 amp braker where the max draw would need a 20. I should be safe to at least try to turn these items on without melting something down because the overload should trip. Thank you guys so much. I can see the light at the end of the tunnel and it isn't an oncoming train, or a $4K repair bill on a $1K to even get started. To clarify I have home made rotary phase converter. It is a 7.5 hp motor and is balanced and started with capacitors. I am sure I will need more explanation on how to run the controls without the phase conveter running, but that will be leaps and bounds from where I am now. I guess it will have to wait. Thanks again.
-Greg Beaman

[PoppaBear10]

hey,

I am in your shoes, can I have a how to on making a home made rotary phaze converter?

[Al_The_Man]

hey,

I am in your shoes, can I have a how to on making a home made rotary phaze converter?

Try previous posts here first like this one, http://cnczone.com/forums/showthread...tary+converter
search rotary phase converter.

Greg, It would be safe to use the exsisting O/L, just turn them up to double or max if they are adjustable.
If the spindle says 220 on the tag, is it fed direct or is there a drive?
What kind of CNC control is on it?
Al.

[tim-tbl]

Hi
You have a problem if your machine is set to run 460 volts it will probably have a transformer to bring 2 of the phases down to 230 volts for the control voltage if that control voltage isn't correct the machine won't run, You also need to consider what kind of phasing you require if your ancillary motors are running from 230 volts the machine will have been orginally wired with 3 live 1 negative and one earth and that would be difficult to replicate, You would probably better trying to step up the 230 volts to 460 however if you are using a domestic power supply be prepared for a huge electricity bill

Regards Tim

[Al_The_Man]

Hi
You have a problem if your machine is set to run 460 volts it will probably have a transformer to bring 2 of the phases down to 230 volts for the control voltage if that control voltage isn't correct the machine won't run, You also need to consider what kind of phasing you require if your ancillary motors are running from 230 volts the machine will have been orginally wired with 3 live 1 negative and one earth and that would be difficult to replicate, You would probably better trying to step up the 230 volts to 460 however if you are using a domestic power supply be prepared for a huge electricity bill

Regards Tim

I think we already covered the control voltage aspect, by suggesting subbing the 1ph 460/120 tfmr to 220/120.
In N America the custom for 3ph machinery is three phase no neutral. And the 1ph control is 110v.
The exception is for 3ph with N. star transformer for Spindle drives, but they are self contained anyway and do not affect the 3ph only supply.
The power consumed (wattage) is the same, whether 230 or 460.
Al.

[tim-tbl]

Thanks for the correction, but I will make one point Ive bought american machines and wired them to european 3 phase supply 415volts instead of 460 and we did find a problem when using power other than the required power, the motors lost alot of torque and they would not run at full speed, eventually we had to step them up, this may not effect a motor that is stepped, down but i can't see how it cannot.
Your thoughts on this would be appreciated as it causes me problems
As for power consumption I wouldn't want the bill for any industrial machine on my domestic supply, british meters work on amperage hours.

Tim