VFD Programing

[les_linton]

Not being an electrician, I’m having a couple issues regarding the 5HP Columbo and the Delta VFD-B.

First off, I am pretty sure that I do not have the display giving me actual rpm readings. So my first question. How do I set the display to read the actual RPM.

Second. Deceleration of the spindle. I spend more time waiting for the spindle to stop for bit changes than I do cutting some of the parts.

I have been looking thru the VFD manual, and it is pretty confusing to me. I see that there appears to be parameters for ramping up and down, but I am getting by with it the way it is, and am a little intimidated at going thru the screens based on what I’m reading.

The keypad is the VFD-PU01

Any help would be greatly appreciated

Thanks,

Les

[Brady Watson]

Les,
You have to get into programming mode by pushing the ProgData button on the display. Then (in section 5-8 in the manual) enter 01-10 to change the deceleration time to something shorter. I believe the default is 10 seconds. I never changed mine since SB set it up.

Changing the display to show RPM is easy...just hit the Mode botton twice each time you turn on the VFD. The default display is in Hertz...from 0 to 400Hz. 400Hz = 24000 RPM or 60 RPM for each Hz.

-Brady

[les_linton]

Thanks for the info Brady.

I guess I thought that when you hit the Stop/Reset button it should quickly ramp down.

After playing with it I find that I need to use the down arrow key to take it to 0 Hz and it stops almost instantly.

RPM was easy.

Thanks again.

Les

[mrdovey]

Les...

From my VFD-B User Manual (You'll need to read about setting parameter values from the keyboard):

Parameter 00-03 is factory set to 00. If you change it to 02 then it will display the commanded RPM. The VFD has no way to know the actual RPM.

Parameter 02-02 specifies the stop method. Values of 00 or 02 cause the spindle to ramp to a stop, rather than coasting. You should be aware that a ramped stop eats more power and may shorten the life of the spindle slightly - but I don't know any specifics.

...Morris

[mrdovey]

Les...

A quick follow-up on the "stop method" parameter: I set my stop method parameter from the factory setting of 03 (stop->coast, fault->ramp) to 02 (stop->ramp, fault->ramp) and found that hitting the stop key will indeed cause it to do a ramped stop.

BTW, I had already changed the "start-up display selection" from 00 to 02 so that the only time I need to mess with the mode key is when I want to examine/set operating parameters.

...Morris

[les_linton]

Thanks Morris.

That's actually what I'm looking for.

I will change that after supper.

Les

[gerald_d]

For a VFD to get a close idea of the actual rpm, it needs to be told the number of poles in the motor. In our case we are talking of 2-pole motors. (4-pole motors will turn at half the speed of a 2-pole). Somewhere in the programming there must be a setting for number of poles if you want speed displayed.

[mrdovey]

Gerald...

The Delta VFD-B has no feedback from the Colombo, so it only knows about what it's telling the spindle to do - and can display info about that. If the spindle is stalled (or disconnected) it'll report incorrect RPM info.

(Info from one of the Delta techs)

...Morris

[gerald_d]

Morris, here (http://www.patchn.com/vfd.html) is the basic formula. The VFD does need to know the number of poles before it can make an estimate of the speed. (The real speed can be as much as about 5% below the indicated speed - it can never be higher). High-speed spindles will always be 2-pole, but I don't know if that is the default setting of the VFD.

[mrdovey]

Gerald...

Yuppers (the default setting is 4-pole). The Delta VFD-B can handle 2 to 10 pole motors.

The controller can only know the actual spindle speed in a closed loop system, and the Delta VFD is not designed for closed loop operation. There is no provision for reading out the actual speed or the amount of power being used - either of which would have allowed me to monitor motor behavior so that my software could automatically determine the "sweet spot" where feed rate and spindle speed were optimized for the current cutter and work material.


The closest we can get with the Delta is to get back the speed we commanded (at keypad or via the RS-485 I/F), a run/stopped indicator, and an indication that the controller has/has not completed the startup ramping sequence. This is all good information, but provides very little in the way of real-time performance information.

...Morris

[stephen.peto@virgin.net]

I am new to using a VFD-B and there are several paramemters that I do not understand. In particular Voltage frequency (fbase), Mid point frequency and Mid point voltage, what should these be set at? Any help would be greatly appreciated!

[watswood]

Stephen,
If you purchased from shopbot they should already be programmed. If you purchased it from a drive dealer then what does the nameplate of your spindle say in regards to voltage and freq? The 01 parameters in the drive are critical and I highly recomend you get them right before you try powering anything up.