Timeline for Slip ring (wound rotor) 3 phase motor, what VFD should I use?
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
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| Feb 9, 2018 at 19:47 | comment | added | user80875 | The real rating of a VFD is the current rating. 2.2kW is just an estimate of the typical motor rating the VFD can drive. To can use a megger test to determine if the motor is ok. Follow the recommendations in the meter instructions. There is a corona inception test for determining the motor's ability to withstand VFD transient voltages. There may be equipment on the market for performing that test. I am not familiar with the test. | |
| Feb 9, 2018 at 10:05 | comment | added | Matthijs van Hest | So to round things up: get a 2.2kw? And how can i measure the insulation to check if the motor is still ok? What values should i get? | |
| Feb 8, 2018 at 21:05 | comment | added | user80875 | The delta connection is the lower voltage connection. If you are intending to operate at 400 volts, I think you should get the dv/dt filter. I would buy a VFD that is oversized so that the intermittent current rating is effectively at least 200% of the motor's rated current. Yes. The motor frame should be grounded. | |
| Feb 8, 2018 at 20:06 | comment | added | JRaef | the issue of leaving resistance in the circuit has to do with replacing the WRIM controller with a soft starter, because a soft starter doesn't have the same current limiting capability of a VFD. But a VFD has more finite control, so you can indeed short the rotor bars as suggested. I too suggest over sizing the VFD, you will regret it if you don't. WRIMs have atypical torque / speed / current curves, you don't want to starve it when you want to accelerate. yes, get the Sensorless Vector Control, same issue. Yes, leave the case ground in place. | |
| Feb 8, 2018 at 17:04 | comment | added | Matthijs van Hest | 2) I use delta, that's 400/380 right? So would this filter still be obsolete? 4) The VFD I'm thinking of has a 1 min overload of 150%. That would do right? But do you suggest a 2,2 kW anyways (in case of motor replacement) 5) mhm okay. I guess so. 6) oversize by how much? 2,2kW sufficient? How much does this sensorless vector drive help? 7) There's already a ground attached on the old setup, just to the case of the motor (not a winding). This should be remained right? 8) Ok so that's just luxury i suppose.. | |
| Feb 8, 2018 at 16:56 | comment | added | Matthijs van Hest | 1) Thanks for confirming. I was already gonna put 2 or more pieces on for redundancy and balance just in case. | |
| Feb 8, 2018 at 16:37 | history | answered | user80875 | CC BY-SA 3.0 |