Need some guidance on selecting a VFD..

I managed to stumble onto a killer deal on a Haberle HL-4 cold saw for the shop. I need to get a VFD for it, but my 3P motor knowledge is ancient and weak. Looking at the data plate on the motor, it has both Y and Delta markings. As this saw is two speed, switch selectable, am I to consider Y or delta wiring as part of the drive selection, or does it mean that the motor rating is different based on wiring? Here is a photo of the data plate on the motor. Things were rough the morning I shot it, and I had to keep my finger over the flash, so that's why it's red tinged.

don't bother, just replace the motor with a singe phase of the same size, about 3HP.

cvairwerks said:

I managed to stumble onto a killer deal on a Haberle HL-4 cold saw for the shop. I need to get a VFD for it, but my 3P motor knowledge is ancient and weak. Looking at the data plate on the motor, it has both Y and Delta markings. As this saw is two speed, switch selectable, am I to consider Y or delta wiring as part of the drive selection, or does it mean that the motor rating is different based on wiring? Here is a photo of the data plate on the motor. Things were rough the morning I shot it, and I had to keep my finger over the flash, so that's why it's red tinged.

Click to expand...

We do need a legible photo of the entire dataplate, to know just what kind of 2-speed motor you have.

There are plenty of suitable VFDs that will accept 220 Vac single phase and make 220 Vac three phase.. I have had good luck with Automation Direct.

you would need a 3phase, 220v, 3kw, 10amp (at the minimum, I like to go a little bigger for peace of mind) VFD.

All the name plate is telling you is that at slow speed its producing 1.2kw @6.9amps and at the higher speed it is producing 2.2kw @ 9amps.

If I was to buy a VFD for that; I would get a 5 horsepower, 10-15amp, 3 phase, 220v VFD.

Motor is probably a Dahlander type with 2 spds and lower current draw at lower speed. No special VFD needed
apart from tylersteez proviso. OTOH power drawn from the motor in use will depend on how large the stock you cut.
if the material is near the largest size the saw is rated for, power draw will be maximal.
If this is unlikely or occasional you could get by with a smaller ie 3HP VFD perhaps with a slightly slowed ramp up programmed in.

BT Fabrication said:

don't bother, just replace the motor with a singe phase of the same size, about 3HP.

Click to expand...

Many coldsaws use odd motors, with extended shafts and what not.

I would not switch motor speeds while the vfd is engaged with the motor though. Dave

beckerkumm said:

I would not switch motor speeds while the vfd is engaged with the motor though.

Click to expand...

Yes. With VFDs, all control (and switching) must be done using the VFD itself, or damage to the VFD is likely.

The motor will run fine on a under powered vfd but it will not develop more power then the vfd can handle. If you seldom use max cut size and speed of cutting action it will be fine.
Bill d

So to address your question, I would recommend you run the motor in a YY 2.2kW mode only (high speed wiring). You can either directly wire the motor to the VFD motor terminals or just not use the low speed motor setting, you would use a VFD speed pot to adjust the motor speed. You do not need to oversize the VFD, but I would look for a 3 Hp VFD that can output at least 10-12A in normal or heavy duty mode. You will want a power disconnect and possibly an E-Stop, to run the motor you use the VFD low voltage inputs and setup the VFD to run in only one direction. Typically once setup you want to autotune the VFD motor, this can typically be done statically or with motion, the latter should be done with the blade removed. You can vary the motor speed with the speed pot, HP will diminish in a somewhat linear fashion proportional to the change in Hz from the motor's base frequency of 60 Hz. So at 30 Hz you would have around 1.5 Hp, I do not recommend going below this. Almost all VFD's allow some form of scaling on the display so you could scale it for something like motor RPM or SFM of the blade.

Many VFD's can be setup for two different motor types/parameters, but in this situation it is not worth the effort/complexity, I also have had more tuning issues with these type of dual speed motors and VFD's.

The Teco L510 is a low cost simple VFD, the L510-203-H1-U is single phase input and can output 10.5A in constant torque. This VFD does not allow for an external braking resistor, so would not be recommended if you wanted the blade to stop quickly. Depending on the blade retaining system, stopping a blade too quickly could cause a threaded retaining system to loosen.

The Fuji Electric FRN0012C2S-7U is single phase input and can output 12A in constant torque and does support an external braking resistor.

The above VFD's are NEMA 1 enclosures so would need to go into a cabinet or electrical enclosure, if you want a dust proof Nema 4/4X/12 type with a power disconnect you might look at something like the Teco E510 series. Teco, E510-203-H1FN4S-U 3 HP, single phase input 230 Volts, NEMA 4/4X/12. output 10.5A in constant torque mode. This series can be used with an external braking resistor.

Thanks all for the assistance. I'm planning on just removing the plug on the end of the cord and mounting the vfd on the saw's stand. I'm not confident in chasing thru all the wiring on saw itself to change anything, as the e stop, start switch and the speed selector are all integral to the internal wiring. I'll chase thru the vfds that mksj listed and see what I can find at a reasonable price and get it on order this week.

You will not be able to use the VFD as a plug and play power source , to do so requires significantly over sizing the VFD and also limits its functions. The VFD motor terminals are to be connected directly the motor terminals w/o using any other means to switch the power to the motor. The VFD functions are controlled by their low voltage inputs or the front panel. If you want to use the power cord and switch gear than maybe consider an RPC, possibly a static converter if the saw is lightly loaded.

MK: Had a brain fart and left off part of the message. The power switch and estop are both 3 pole single throw switches and wired between the line cord and the motor speed switch. I intend to just leave them in place and in the on position and just use the vfd switched to control the power. I just need the saw to run stock speeds. I'm only cutting tubing and bar stock well under the saw's capacity...2" od x .120" wall is about the biggest stuff I'll ever cut with this saw. After a little checking, a 3 hp vfd is less expensive than an rpc and takes up a heck of a lot less space, as the vfd can be mounted on the saw stand.