110v 3 phase for baruffaldi turret

[jonnydeen]

Need to figure out a solution for supplying 110v ac 3 phase to my baruffaldi RH150 turret. Is there any VFDs out there that output 110? Dont even need speed or frequency control. Just controlling it with relays.

[Muzzer]

Most VFDs should be able to do that. You need to enter the "nameplate" values (voltage, frequency and max phase current) when you set it up - this is where you specify the max voltage (this will be at 50Hz). Make sure you select "V/f" mode, not open loop vector.

[jonnydeen]

Thanks Muzzer. What a clear and concise answer. That helps a great deal

[m_c]

If the RH timing is anything like a TOE, I'd say you'll really need to oversize the VFD, fit a braking resistor, and use the VFD to control this, as I'd very much doubt a VFD will be able to handle the rapid switching these turrets need by switching the 3 phase after the VFD.

[jonnydeen]

If the RH timing is anything like a TOE, I'd say you'll really need to oversize the VFD, fit a braking resistor, and use the VFD to control this, as I'd very much doubt a VFD will be able to handle the rapid switching these turrets need by switching the 3 phase after the VFD.

thanks for that m_c
suspect they may operate in a very similar manor.
the motor brake is first deactivated, the motor turns moves the turret wheel forward to unlock and continues to rotate the turret counter clockwise until it moves just past its next tool. it then rewinds direction until the turret is retracted to the lock position and the motor brake is enabled.
feedback by way of a six position rotary switch for position and a microswitch for lock/unlock (turret forward/back)
i can imagine stopping the turret rotation fast enough is quite important for these turrets.
Electrical manual TA-RH.pdf
are you running one? i would very much be interested in finding a pre-existing or similar macro for it.

[m_c]

Ah, it looks like the RH is a simpler turret, as it only rotates one direction without the complicated and time critical locking/direction reversal of the TOE turrets.
I've got a TOE (or at least all the parts of one after a slight mishap), and I ended up controlling it via a PLC, using my rotary phase converter to power everything.

The issue is although it's quite a small motor, it's pushed hard due to the inertia of the turret. As I said, you'll probably need to add a braking resistor to brake the motor fast enough before reversing it, and possibly increase the current limiting above the rating for the motor to get fast enough acceleration (make sure the thermal switch is wired in to kill things if the motor does overheat) but given the slacker time requirements of the RH, a VFD should handle it quite comfortably.

I'm guessing this is on Denford lathe?
If it is, Denford did use VFDs on some lathes to control the turret, so it could be worth asking over on the Denford forums to see if anybody knows what size of VFD they used, and how it was configured in terms of acceleration/deceleration.

[jonnydeen]

Ah, it looks like the RH is a simpler turret, as it only rotates one direction without the complicated and time critical locking/direction reversal of the TOE turrets.
I've got a TOE (or at least all the parts of one after a slight mishap), and I ended up controlling it via a PLC, using my rotary phase converter to power everything.

The issue is although it's quite a small motor, it's pushed hard due to the inertia of the turret. As I said, you'll probably need to add a braking resistor to brake the motor fast enough before reversing it, and possibly increase the current limiting above the rating for the motor to get fast enough acceleration (make sure the thermal switch is wired in to kill things if the motor does overheat) but given the slacker time requirements of the RH, a VFD should handle it quite comfortably.

I'm guessing this is on Denford lathe?
If it is, Denford did use VFDs on some lathes to control the turret, so it could be worth asking over on the Denford forums to see if anybody knows what size of VFD they used, and how it was configured in terms of acceleration/deceleration.

its actually an Italian AVM MAS165s CNC sold by Meggitt machine tools
its quite difficult to find a 110v output vfd. is the TOE 110v?
been told by a nice chap at inverter drive supermarket that while many inverters can run Voltage/frequency mode with fixed frequency and voltage set to 110.(much like muzzer has said) The issue is that inverters are electrically dirty and with dc bus voltage of around 300vdc can lead to rather nasty peaks which can be damaging to the motors insulation. Not so bad if the motor is rated for 240v but not great at 110v

[Doddy]

I know nothing of the subject matter - but reading this thread (a) cos it's a Sunday morning and too early to be making noise outside and (b) always interested in turret/toolchanger design for a lathe.

Given your last point, on the dirty output from an inverter. There's an easy and relatively cheap solution for that - depending on the power that you're looking for - pick up a 2nd-hand site transformer to take 220 to 110, then spec out a 110v in/out inverter. Yes, this comes at a cost for the transformer (relatively low) and the space required to house it - your call on that - but it resolves the problem.

There are VFDs rated at 220V in, 110V/3 out - at least so they claim, but I do take your point on dirty spikes. A decent set of filters could address that to some extent - but it's again your call on whether you trust that solution.

Another wacky idea that amalgamates both the above to give the worst of all worlds - use a 220V inverter and a three-phase transformer to bring it down to 110VAC/3.

Or replace the 3phase motor - though I'm guessing from this thread though you're trying a light touch on the turret assy.

Sorry - just random thoughts - none of which are particularly elegant.

[jonnydeen]

I've had a look for vfds with 110v outputs but have only come across 110v input, 220 out. I've luckily got plenty of space for electronics so housing a transformer is not an issue. Can anyon recommend any 110v output vfd

[m_c]

I'd guess most VFDs will simply rely on the electronics to provide a lower voltage output, but regardless unless the motor is inverter rated (higher voltage insulation), then even a VFD running at rated voltage can cause insulation breakdown due to switching harmonics. You'd typically prevent that problem by adding a sine wave/sinusoidal filter after the VFD, however I'm not sure if you can get them designed for 110V.

Would I be right in guessing this lathe originally ran of normal 3 phase, and already has a step-down transformer for the turret?
In which case, I'd look at using a boost VFD (230in 380out), and adding a sinewave filter if you're concerned about insulation issues (although the transformer will be the part likely to fail, as they are very unlikely to be inverter rated).