Connecting a Bridgeport Interact 1 MK2

[Callan]

Hello all! I just purchased a bridgeport interact 1 mk2 and I have it here sitting in my garage. I have some experience with CNC but this seemed like a good machine to own and have some fun with!

Anyway i am looking for a solution to connect the mill. Unfortunately i do not have access to 3 phase power where I am located so this is my first challenge.

I have dome some reading and it seems like american rotary makes one of the best rotary phase converters and priced well too. Their CNC phase converters allow no more than +- 5% voltage variance between the phases so it should work well for my application.

I have all the manuals with the machine and it calls for a 20 KVA power rating. Now this doesn't really make sense to me because it calls for a main breaker of 50 amps at 220v which gives about 10 KVA.

My main questions is what size of phase converter am I going to need. I will never get this thing to full load and I don't want to spend a huge amount of money on oversizing a phase converter that i will never take advantage of.

The machine is 9HP by what i'm told so I really don't see where the 20 KVA is going, but maybe someone can make a good suggestion for me?

The machine was previously wired for 575 and I will be keeping it that way since i already have a step-up transformer ready to go and I don't feel like setting the machine up for 220 if I already have the transformer.

Any info is greatly appreciated! I want to see this thing come alive so I can start working with it.

Thanks!

[gandalf69]

Originally I connected by Interact1 mk2 to 440v 3 phase with 10A circuit breakers. They tripped regularly at switch on presumably due to inrush to the transformers. Now it is connected via 20 breakers and does not trip out. I have no idea whether it would have a problem under high spindle torque.

[gus]

I have run these machines on a homemade 5 hp rotary converter, on a 30 amp breaker, 10 ga wire.

[Callan]

ok well it sounds like I will be ok. I have a 60 amp feed at 240v and I'm looking at either a 10 or 15hp phase converter going through an 8KVA transformer.

I think this puts me in a safe range where i will be ok. I don't think i would even want to try and max out a 9hp motor on a mill lol.

Thanks for the info! Can't wait to get this thing fired up!

[gus]

Transformer?

[Callan]

yeah the mill is wired for 575V

[Al_The_Man]

It is best to ensure that the single phase controller fed circuits are on the windings that are connected to the 240v 1 phase feed, not the artificial phase.
What configuration is the transformer Star/Delta or?
Al.

[Callan]

ok that makes sense, i guess I will have to look at the wiring diagrams here to determine which to hook up where and connect the controller circuits to non-artificial leg.

The transformer says delta/star on it. I am going to get my uncle who is a master electrician to help me out on the connection.

Thanks for the tip on the controller circuits!

[gus]

most of the bridgeports have a big internal transformer you move jumpers to set the voltage

[Al_The_Man]

Originally Posted by Callan ok that makes sense, i guess I will have to look at the wiring diagrams here to determine which to hook up where and connect the controller circuits to non-artificial leg.

You will probably find that there is a 1 phase transformer with 120v secondary in the enclosure, this is the one to ensure is fed by the right two phases.
Once you have done that, then if you have to reverse two because of motor rotation it can be done with by reversing the two 240v legs, this will maintain the correct 120v 1 ph connection.
Al.

[machintek]

But what to do with the spindle drive? This machine has either a Contraves or KTK spindle drive. It requires 3 good phases.

George

[Callan]

i have a CNC digital rotary phase converter here from American rotary. supposedly the 3 phases are balanced within +-5% so i should have 3 good phases.