Thread: While we are all on VFD's...Vector drive recomendations.

Hi Guys,
Since we seem to have VFD's on the brain right now, does anyone have recommendations for a good 2hp vector drive?

There is a pretty high chance i will want to put one on the Holbrook. It has one drawback that i don't like (other than the 1" spindle bore), that is the speeds are not exactly in a geometric progression. Top speed is 2000rpm, next one down is 995rpm.

I'll be looking at a 415v 3 phase in same out.

Cheers,
Ew

Originally Posted by Ueee

Hi Guys,
Since we seem to have VFD's on the brain right now, does anyone have recommendations for a good 2hp vector drive?

There is a pretty high chance i will want to put one on the Holbrook. It has one drawback that i don't like (other than the 1" spindle bore), that is the speeds are not exactly in a geometric progression. Top speed is 2000rpm, next one down is 995rpm.

I'll be looking at a 415v 3 phase in same out.

Cheers,
Ew

That's a 3 speed motor. Are you aware that there are 'issues' in hooking up a VFD to multispeed motors? Or do you intend to replace the motor with a single speed one?

PDW

Originally Posted by PDW

That's a 3 speed motor. Are you aware that there are 'issues' in hooking up a VFD to multispeed motors? Or do you intend to replace the motor with a single speed one?

PDW

I thought that was only for trying to hook up a multi speed motor on 240v 3 phase. My thoughts are just to use the middle speed and let the VFD do the rest. it only has to get a 4:1 range to get the same speeds as the lathe comes with. Apparently changing the motor is a PITA, not only do you have to remove the electrical cabinet to get the motor and gearbox out and the motor has a splined shaft and drives the gearbox direct.

Ew

Originally Posted by PDW

That's a 3 speed motor. Are you aware that there are 'issues' in hooking up a VFD to multispeed motors? Or do you intend to replace the motor with a single speed one?
PDW

There should be no problem provided the VFD is not outputting anything while switching between speeds (Stuart has drilled that into me by now). A 3 way switch cans then be used. If you wanted full "brace and bib" protection you could put the switch inside a box with an electrical lock out from the VFD.

Originally Posted by BobL

There should be no problem provided the VFD is not outputting anything while switching between speeds (Stuart has drilled that into me by now). A 3 way switch cans then be used. If you wanted full "brace and bib" protection you could put the switch inside a box with an electrical lock out from the VFD.

Or use the switch that the lathe already has that disconnects power from the motor before changing the contacts around. You pull the lever out before it can be moved. If this switch fails apparently the contacts burn out from arcing real quick.... Like i say thought i only need 4:1 (motor is 2,4 and 6 pole) to get the motors original speed range anyway, so i doubt i'll need to use the different speeds.

FWIW the motor claims to be 2hp in all three speeds, unlike the other multi speed motors i have seen.

Ew

Originally Posted by Ueee

Hi Guys,
Since we seem to have VFD's on the brain right now, does anyone have recommendations for a good 2hp vector drive?

There is a pretty high chance i will want to put one on the Holbrook. It has one drawback that i don't like (other than the 1" spindle bore), that is the speeds are not exactly in a geometric progression. Top speed is 2000rpm, next one down is 995rpm.

I'll be looking at a 415v 3 phase in same out.

Cheers,
Ew

recomend i cant but ive got a SEW one that i have no use for. From what i understand they are a very good unit.

Listen to BobL, Ueee. Don't open or clos the VFD connections to the motor unless the VFD outputting 0Hz (and is not in braking mode) or it has been stopped (via Stop button or stop command on a remote control terminal.
If you can positively achieve that, you can use all three speeds.
Poducing 2 Hp at all three speeds sounds unlikely to me too, but there is much more I don't know than I do

I feel I should chime in here with some comments...

I've done lots of control systems for multiple pump systems where the vfd is shared between pumps, each motor has two contactors, one which connects it to the 3ph vfd bus and one which connects to the 3ph mains, typical motor sizes are in the 11 to 22 kw range, biggest I've done was 8x250 kW, but that system had a vfd per pump. we've done 100 kW x 8 pump systems that shared a vfd, but the vfd isn't rotated until the system goes through a shutdown cycle. The other pumps are called using soft starters, too big for DOL.

You ramp a motor up on VFD, then when you call the next pump in sequence, you drop the vfd contactor and pull in the mains contactor, just before dropping the vfd contactor, you switch from run to stop, delay a period of a few hundred milliseconds to allow the motor flux to decay, then open the vfd contactor, and pull in the mains. Then pull in the next vfd contactor and ramp at full acceleration to the minimum Hz and then switch to normal acceleration when the second pump is running. Going down is not the same, you are switching a vfd to a spinning motor, and the start mode changes from ramp start to spin start, also the contactor delay needs to be long enough for the stator magnetic field to have collapsed, so that the motor isn't running as a generator when you pull in the vfd contactor.

So.. switching a motor on the output of a vfd, is not going to kill the vfd, it's best if the motor isn't spinning when you switch the vfd output on, and conversely it's best if the vfd isn't outputting when the motor is connected or disconnected.

So as Joe and Bob have already said, don't switch the outputs when the vfd is running, but it probably isn't going to kill the vfd...

Ray

Here's a video of a mill being switched on and off, using the normal on/off switches, so the vfd is outputting 60 hz when the motor is turned on/off.

http://www.youtube.com/watch?v=PPAM_...&feature=share

Originally Posted by jhovel

Listen to BobL, Ueee. Don't open or clos the VFD connections to the motor unless the VFD outputting 0Hz (and is not in braking mode) or it has been stopped (via Stop button or stop command on a remote control terminal.
If you can positively achieve that, you can use all three speeds.
Poducing 2 Hp at all three speeds sounds unlikely to me too, but there is much more I don't know than I do

Most motor power ratings are nominal anyway
Doing the power calc with the numbers provided by the manufacturers on the nameplate I rarely seem to come up with the actual power(s) stated on the name plate.
Numbers that I calculate that are too high may be explained by a motor efficiency but sometimes I get numbers that are lower and any efficiency factor is only going to make them lower.
If the actual motor power across the 3 speeds is 2.4HP, 2HP and 1.6HP they are just as likely to still call them all, 2HP.

I think the cutting the motor while the VFD is running has been done to death....

All i am looking for is a VFD recommendation. All i have experience with are the huanyangs.

I doubt i will need to 3 speeds, If i can run from 940 to 2880 with it hooked up as a 4 pole motor i will loose no top speed and no low speed. I still have a 2 speed gearbox and a backgear to use too. If i do i need the extra speeds i can wire the 3 speed lever to tell the vfd to stop, then change the speed and start again. The only issue would be if the motor is still spinning. It should be fine with a really quick ramp down as it has a clutch anyway and all it has to stop is itself.

Ew

Originally Posted by azzrock

recomend i cant but ive got a SEW one that i have no use for. From what i understand they are a very good unit.

Hi Aaron,
What model is it?

Ew

Originally Posted by Ueee

All i am looking for is a VFD recommendation. All i have experience with are the huanyangs.

With sensorless vector drives, the drive has to "tune" itself to the motor parameters, the idea of switching number of poles, between 2,4,6 poles would defeat the "tuning" functions, some drives will auto-tune, but generally that process takes a minute or two.

You wouldn't want to have to re-tune the drive every time you changed number of poles. There might be drives that support multiple switched configurations? Can't say I've ever seen one..

So I think you might be stuck with simpler v/hz drives..

Ray

Originally Posted by RayG

With sensorless vector drives, the drive has to "tune" itself to the motor parameters, the idea of switching number of poles, between 2,4,6 poles would defeat the "tuning" functions, some drives will auto-tune, but generally that process takes a minute or two.

You wouldn't want to have to re-tune the drive every time you changed number of poles. There might be drives that support multiple switched configurations? Can't say I've ever seen one..

So I think you might be stuck with simpler v/hz drives..

Ray

I think he's planning on leaving the switch on the 4 pole position and using the VFD to cover the 2 pole & 6 pole speed range. Effectively turning it into a single speed motor varied by the VFD. That should work fine with the g/box and back gears for torque multiplication at low speeds.

There are a couple of nice new Danfoss units sitting on the floor here but they're RS485 control systems I think and while there's provision for a pot, I've never found one (though I haven't looked hard). Probably more something you could use, Ray, rather than Ewan, not that I'm intending to move them on at this time. They're a piece of equipment in search of a requirement....

PDW

Originally Posted by RayG

So as Joe and Bob have already said, don't switch the outputs when the vfd is running, but it probably isn't going to kill the vfd...
Ray

That is consistent with my inverter drive surviving speed changes (4 pole operation to 2 pole, and back) on the Arboga EM825 with the motor running. That was before I realised it was not a good idea. Now I just stop the VFD before switching motor speeds. The plan is to put in an interlock (still just another item on the project list). BTW it is a simple Vxf drive, not sensorless vector type.
Cheers,

Bill

Originally Posted by Ueee

Hi Aaron,
What model is it?

Ew

g'day mate its a 4kw movitrac lte
mc lte a0040-5a3-1-00

aaron