Motor/VFD Question 2

[MagneticFlux]

Greetings all,

I would like some opinions/suggestions on an issue being experienced with a VFD and motor.

Motor Specs:
Volts 460
F.L. Amps 239
S. F Amps 275
RPM 1200
Hertz 60
HP 200
Duty CONTINUOUS
TYPE TD
Frame 447T
Serv. F. 1.15
Phase 3
Design B
Code G
Insul Class F
Eff 100% 96.2
Connection 6 Lead Star-Delta
Link

http://www.leeson.com/CnxDocRequest/PublishedPDF/dwg-006131301_00519001_545780_365.pdf

Drive Specs:
Product: Allen Bradley 23C-D460A103NNMANN
Description: PowerFlex 400, Fan & Pump Packaged Drive

Version Voltage Code 480 VAC, 3 PH
Output Current 460 Amps
Human Interface Module Fixed Keypad
Enclosure IP20 / Type 1
Version RS485
Frame Size H

Setup:
Motor is driving a P type fan via direct coupling
Motor connection = DELTA (connection has been verified twice)
Drive tuned and configured for 200HP motor, all settings default with exception to motor nameplate data, voltage input and auto-tune data.
Motor Data = (matches above info)
Voltage Input = 480 Volt
Auto-tune = calculated by VFD based on above info
Motor Control Mode = V/Hz
Application Mode = None, no PID inputs, being controlled via HMI

ISSUE: (Note that I am not performing the install/setup, I got involved because someone asked me to look into this).

The motor will not come up to full speed before O/C limit is reached. With frequency set-point at 60Hz: as the motor ramps up to speed (ramp time = 30 seconds), at +18HZ an over current alarm is indicated on HMI. Longer ramp times have no effect. The VFD will ramp up to ~18Hz and go into 'current trim mode' as this is highest frequency achievable before current output peaks at ~275 amps(SF amps). Adjusting the frequency beyond 18 Hz triggers O/C alarm.

Motor manufacturer recommends leaving the motor connected in delta and starting ATL to determine if this is a drive or motor issue. This was thought I had as well but Size 5 starters are not laying around like they used to be 20 years ago so, for the time being, that option is off the table. My thoughts are centered on drive parameter settings but the settings are as basic as they need to be for nominal operation. Any thoughts?

 

[jraef]

The photo you posted is a PowerFlex 400, you asked about a PowerFlex 753, they are different animals.

Still, the issue of Y vs Delta connection is no different, still irrelevant. The first person may have been somehow conflating this with the LINE SUPPLY configuration. All PowerFlex drives can be configured to allow them to be used on a Delta power system, but some other VFDs are only allowed to be connected to a Wye system (typically Asian mfrs). But even then, the PF400 can also be reconfigured to be used on a Delta system so I don't know why he would have said that... maybe he was a noobie.

I once had an ME from a pump mfr sell a customer a new 100HP pump to which I applied a VFD to maintain a tank level against a variable inflow. When it failed to keep up with the inflow even at full speed, I investigated the application and found that they had abandoned an old pump in place, and it had a 400HP motor on it! When I questioned the validity of replacing it with a 100HP pump, the ME told me to just turn up the speed...


" We are all here on earth to help others; what on earth the others are here for I don't know.
" -- W. H. Auden

 

[MagneticFlux]

@jreaf: The photo posted of the VFD nameplate is a PowerFLEX 753

http://ab.rockwellautomation.com/Drives/PowerFlex-753

 

[jraef]

Oh, duh...

I guess I saw what I was predisposed to see:

Drive Specs:
Product: Allen Bradley 23C-D460A103NNMANN
Description: PowerFlex 400, Fan & Pump Packaged Drive

OK then. Did you perform an AutoTune on that 753 drive? Even if you are using it in V/Hz control, it still needs to do an AutoTune. I don't know why, but I know it does.


" We are all here on earth to help others; what on earth the others are here for I don't know.
" -- W. H. Auden

 

[MagneticFlux]

@jreaf: Initially, yes, a Static auto-tune was performed. However, the drive has be reset to factory defaults in preparation for this weekends trial setup per AB Tech Support recommendations.

 

[jraef]

I sent you an email, but now please edit your post to remove the address, otherwise it attracts spam-bots to the site.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[waross]

From the spec plate it appears as though the drive may be either a 250 kW drive or a 200 kW drive.
Is this something that is set in the parameters?
If the drive was inadvertently configured to 100 kW, that may explain the low current limit.
Is this possible Jeff, or am I lost in lala land.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[MagneticFlux]

@waross: The drive is a setup for 480 Class (right data column of nameplate)

 

[iop95]

I'm pretty sure the problem is in drive current measurement.
Y motor connection is working and for 48Hz output, motor torque result about 2000Nm... much above maxim motor torque.
In delta, FLA is reached at lower speed but real current is much smaller than what drive see; this is the reason drive stop at 18Hz.