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Parameter Settings for Powermatic Inverter

M

Michael Kurylo

Joined
Jan 18, 2012
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Location
Howell, MI
I recently purchased an 11 year-old Powermatic 4224 and finished wiring it this weekend. It is not running in a normal mode and only rotates when I press the "jog" button on the inverter. As a bit of mental insurance I toggled through all of the parameters of the VFD015B21B inverter and wrote them down. Does anyone have a set of the original settings as released by Powermatic? I would like to verify that the inverter is set up properly before going any further. The last couple of pieces of information I have are as follows; the previous owners had left the lathe in storage for over a year, the power is currently wired for 1PH, 220V. When the lathe is powered up the inverter panel displays are F=0.00, H=0.00, A=0.0, -Frd-, STOP, and FWD. Any help would be greatly appreciated.

Mike
 
Based entirely on the model number of the inverter that you supplied in your post, I was able to dig up this manual.

http://www.galco.com/techdoc/dlpc/vfd015b21b_um.pdf

If it was me, I would study the parameter settings and compare them to the manual. Of course, taking into account the way that the inverter and control panel are wired.

I just recently upgraded an older lathe with an inverter and 3 phase motor. I can't speak of the inverter in your lathe, but I found it not too difficult to wire a control panel and adjust the inverter parameters accordingly.
 
I'm not familiar with that one but the inverters that I've installed that were aftermarket had a reset button that set everything back to a set of factory specs. That might be a good place to start if it has one.
 
Thank you all for the advise. I read through the manual for the Delta inverter and noted a few parameters that were outside of the recommended range. When I called Powermatic tech support for a list of settings to compare with my lathe they asked if the inverter was locked or unlocked. Since I was at work and not near the lathe I had no way of knowing. Their next recommendation was to check the power switch on the headstock and the remote switch. It is getting frustrating having a lathe that does not go "roundy-round"!
 
All it means if the inverter is locked is that it would be necessary to do a full reset and start from there setting everything that is different from factory default conditions.

Depending on the inverter, it might be able to perform an automatic tuning procedure. Otherwise, it might be necessary to get some motor parameters from the manufacturer or from Powermatic and enter them manually. These parameters "tune" the inverter commands to the motor for optimum stability.
 
With my inverter I found that starting the motor without a load confused the vector mode of the inverter. When it started it wouldnt always start going the same direction. So I basically had to turn off any 'tuning' that had been done. I changed it to Voltage/Frequency mode and everything started working normally.
 
I don't know about that particular inverter, but the tuning procedure for many inverters entails first operating the motor bare (includes removing the pulley) and then operating with a typical load (whatever that might be -- my assumption is a maximum load). If the wrong parameters are entered manually, it can result in unstable operation. The downside of V/Hz operation is reduced performance in speed regulation and output power.
 
I agree with your comments on V/f mode, but I've not quite been able to come to terms with it in this application. When discussing a wood lathe, what constitutes maximum load? Driving an empty spindle doesn't seem like much of a load. Chuck up a large bowl blank and dig your gouge into it?
 
Alan Van Art said:
I agree with your comments on V/f mode, but I've not quite been able to come to terms with it in this application. When discussing a wood lathe, what constitutes maximum load? Driving an empty spindle doesn't seem like much of a load. Chuck up a large bowl blank and dig your gouge into it?
Click to expand...

With woodturning, the load is highly variable and constantly changing unlike a typical industrial application that may be driving a conveyor or a milling machine where the loads are constant and well defined. This makes defining the PID gains in sensorless vector mode something of a guessing game.

When designing feedback control systems, one of the rule of thumb design parameters for stability is that the reflected moment of inertia of the load should ideally be no greater than three times the motor's rotor moment of inertia. Load moment of inertia values greater than that can be accommodated (up to perhaps 10X rotor moment of inertia) by tuning the PID (proportional, integral, and differential) gain values for critical damping.

My thought for the most stressing case scenario would be the heaviest piece of wood that you would reasonably mount onto the spindle and turn with the pulley set to the high speed range and motor RPM at 50% base (about 875 RPM). Note that this is not necessarily the heaviest piece that you would ever consider turning, but the heaviest piece that you would consider turning for the stated conditions. Obviously you would start off turning really heavy pieces in the low speed range.

The reason that the high speed range is more stressing is that the moment of inertia of the load reflected back to the rotor is the actual load moment of inertia times the square of the drive ratio. For the Powermatic, the reflected load moment of inertia would be multiplied by 3.44 in the high speed range while in the low speed range it would be multiplied by 0.48. The difference is a whopping factor of 7.17 -- quite significant. That is a good reason to always start out in the low speed range unless turning pens or bottle stoppers.

It is easy to tell if the gains or other parameters are not set correctly. The most likely scenario is initial sluggish response lagging behind the speed control setting followed by speeding up and overshooting the speed setting followed by slowing back down. This fast-slow-fast-slow surging motion is likely to go divergent especially when you start turning.
 
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I missed your comment that your problem was occurring when operating without a load. That sounds like some parameter must not be correct or that a PID gain is not correct. Check the ramp up and down settings also. Try increasing the time that it takes to ramp up and down to see if that helps. If it initially starts out in the wrong direction, that is a bit of a head scratcher. I used to pull out my hair over things like that, but now that I don't have any noggin hair, so I no longer have that problem.
 
I'm not sure about the Delta B drive but I do know about the Delta S1 drive which they are currently using on a number of Powermatic and Jet machines.

If the drive is "locked" you can view parameters but you cannot change them. It would seem that a reasonable plan would be to reset the drive to factory settings and start all over. But you need to "unlock" it to do a reset. In other words, without the password you can do NOTHING.

I'd be interested to know if your B drive is locked or not -- I'm betting that it is.

Bill
 
Bill, when you do a reset back to default values, it also resets the password protection to NONE (maybe not for all inverters, but it does for the ones that I have experience with which are mostly Baldor industrial vector drives series 18H and H2). One reason for doing a reset is to be able to tweak settings in the unit when it has been locked and nobody remembers the password. Of course the reason for password protection is to reduce service calls to "fix" problems when somebody decided to monkey around with the menu out of curiosity.
 
Bill Boehme said:
Bill, when you do a reset back to default values, it also resets the password protection to NONE (maybe not for all inverters, but it does for the ones that I have experience with which are mostly Baldor industrial vector drives series 18H and H2). One reason for doing a reset is to be able to tweak settings in the unit when it has been locked and nobody remembers the password. Of course the reason for password protection is to reduce service calls to "fix" problems when somebody decided to monkey around with the menu out of curiosity.
Click to expand...

Sorry for the very delayed response...

Bill B -- In my experience also, resetting most drives resets the password to NONE. But, according to an email from Delta Sales/Eng support and my testing on an unlocked drive, that's not the case for the Delta S. You need to know the password. My question to Delta -- are you telling me that if I forget my password, I've bricked the drive? The answer was yes, almost. They can reset it at the factory but it cannot be reset in the field. There might be a reset test point on the board but I'm guessing you'd have to take it apart to get to it.

Bill (R)
 
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