VFD or Rotary Phase Converter for Bridgeport?

[yankeerider]

I just got myself a vertical mill, and now I need to feed it some 3 phase power. (Actually, I still need to get the base home, but that's another story.) I've researched TBN and other places, and can't decide between a VFD and a rotary phase converter. (Although a number of people seem to run mills on static converters, since that doesn't provide reverse and it limits power, I'm not considering a static.)

Any real world experience between the VFD and rotary options? I like the idea of the extra speed variability with the VFD, but are they noisier than RPC's? There was some discussion of that on the Practical Machinist forum.

TIA for any comparative info.

 

[Dakota_male]

I just got myself a vertical mill, and now I need to feed it some 3 phase power. (Actually, I still need to get the base home, but that's another story.) I've researched TBN and other places, and can't decide between a VFD and a rotary phase converter. (Although a number of people seem to run mills on static converters, since that doesn't provide reverse and it limits power, I'm not considering a static.)

Any real world experience between the VFD and rotary options? I like the idea of the extra speed variability with the VFD, but are they noisier than RPC's? There was some discussion of that on the Practical Machinist forum.

TIA for any comparative info.

I added a VFD to both my drill mill 2 HP and Lathe 2HP , it will give more speed control and and motors run cooler and more efficent.

 

[mikegt4]

I just put a Teco EV on my Millrite. It works perfectly and has more configuration choices than you can imagine. I got mine from Dealers Electric.
Variable Frequency Drive, AC Motor Drives, Pool Pump Motors, Marathon Electric 3 Phase Motor, Teco Westinghouse Distributor

 

[BHD]

I used a static converter for years on my mill untill I got three phase, and you reverse a motor the same way as with three phase, switch any two wires, I just use a reversing switch, on my mill.
(personally I could tell little difference on the mill running on the converter or the true three phase)


I have a rotary converter, as well and only used that on the walk in cooler and freezer, since they start under load,

 

[KitC]

For a milling machine, I'd recommend a VFD as Mike mentioned. Make sure you find one that matches your input/output phase and voltage.

For a lathe, a rotary phase converter works fine.

I've got 2 mills on VFDs and 3 lathes on RPCs.

 

[sandman2234]

I have two mills on static's and reversing them isn't a problem. The switch on the mill is for that, the static just provides incoming power that the mill uses in which direction it wants. You can even reverse it during operation, if that is what you were alluding tne is a varible speed Bridgeport (2J) David from jax

 

[yankeerider]

Thanks everyone. Somewhere I had read that with a static converter the reversing switch position didn't matter. Either I didn't understand what that individual was saying or they were just wrong.

Since it seems that none of you have any complaints about noise from VFD's, I'm gonna go in that direction. Thanks for those links!

 

[tommu56]

I use actech single to 3 phase drives at work better than a phase converter in my opinion

Lenze-ACTech SMVector Series



tom

 

[Mace Canute]

I have read posts from knowledgeable people who said you must use the VFD for all switching operations and you will damage the VFD if you try to use the switches the mill came with.

 

[tommu56]

I have read posts from knowledgeable people who said you must use the VFD for all switching operations and you will damage the VFD if you try to use the switches the mill came with.

Very true they don't like opening the motor leads ( ie drum switch to reverse)

but a 3 way selector switch on off on works connected to drive.

tom

 

[kennyd]

I have a Teco FM50 VFD on my lathe...no regrets.

Picasa Web Albums - Ken - Clausing 4900

 

[mikegt4]

I have read posts from knowledgeable people who said you must use the VFD for all switching operations and you will damage the VFD if you try to use the switches the mill came with.

IF you put any switches between the VFD and the motor there will be problems. But, you can utilize the original drum or push button switches for low voltage remote control of the VFD. This will allow the VFD to be mounted anywhere and, as with my Millrite, still use the original switch which was readily at hand. Three small wires between the drum switch and the control terminals on the VFD allowed the FWD, OFF, REV to function as they did originally. If you want something different than the original arrangement, you can design your own control panel.
There is a slight humming noise (and cooling fan noise) from my VFD but you don't notice it after a while.

 

[sandman2234]

I don't hear anything from my static, costs a lot less, let's me use the Bridgeport switches and if I burn it up, not as big of loss. My machine is variable speed so if that is what your after, then go vfd. David from jax

 

[JRP]

"..... you will damage the VFD if you try to use the switches the mill came with."
Not true. As mentioned in another post above, the drum switch can be used as the forward/reverse switch for the VFD. The red, white and black wires in the photo were wired to the drum switch. The motor wires connect directly to the VFD output, not to the drum switch. Fuses had to be installed for the power.

I had this one just installed on a Bridgeport that came with a computer. The VFD can provide 3hp, so it will give the full 3hp available from the 2hp head. Apparently the mill motor is strong enough that you can load it to 3hp as long as you use it for less than 30 minutes, then let it cool.

This is one I used:
FM50-203-C

I didn't have much to spend. At $185 it is less expensive than a converter, smaller, easier to install, and mine is quiet. It clipped onto a metal rail called DIN inside my mill computer control. It was also set up with "deceleration", which uses the VFD to brake and stop the tool in 1.5 seconds.

BTW, if you turn the mill down with the VFD the drilling torque stays the same. Not good for big holes. If you use the belt or gear/mechanical speed ratio your drilling torque goes way up. My VFD is set at 60, which is the wall power cycles. I adjust the speed with the Bridgeport crank and gears.

You will love the Bridgeport. I bought mine just to drill with, but it is much more useful
than that.

 

[JRP]

kennyd, your lathe project is awesome. nice job

 

[yankeerider]

Thanks, everyone. I got a TECO EV series VFD and the machine came to life this morning. I had been concerned about humming noise based upon some posts I read elsewhere, but I needn't have had any concerns. The only noise was from the cooling fan in the VFD, and that is not at all objectionable. The soft start is really cool. I will be wiring the fwd/rev/off switch on the mill to the low voltage control functions of the VFD.