Ruskied
Member
This is more of a VFD question where a PLC is used to monitor/trend several datalinks. The application is to tilt a vessel with two AC motors driven by one VFD as the vessel is filled with molten steel. The application is said to be constant torque with Volts/Hz control mode (no encoders). At certain vessel weight, the VFD can't move the vessel anymore. VFD was sized based on motor (both motors) FLA and Volt nameplate data. At first glace, the VFD looks to be undersized. However, looking at the datalink trends, VFD never reached max. power, not even half. VFD appears to be overheating due to being ran at 200% of rated current. Motor FLA (both motors) is 82 Amps while the VFD overheated at 144 Amps (running for ~3 sec). It's a rockwell powerflex 753 heavy duty 77 amp drive (can operate at 115 Amps for 60 sec. which is more than it needs for this application).
Questions:
1. Would this be a constant torque application?
2. Drive current limit is currently set for 144 Amps, would lowering that help?
3. Are there any other options left before resizing the drive? (ex. boosts, other operating modes)
Any ideas or thoughts or links for further reading would be greatly appreciated.
Regards.
Questions:
1. Would this be a constant torque application?
2. Drive current limit is currently set for 144 Amps, would lowering that help?
3. Are there any other options left before resizing the drive? (ex. boosts, other operating modes)
Any ideas or thoughts or links for further reading would be greatly appreciated.
Regards.