Danfoss VLT ® Series 3000 series adjustable frequency drive

Selection, derating, and debugging practices

1. Application of derating curve

The derating curve in the appendix of the manual is the ultimate guarantee for ensuring the safe operation of the frequency converter under all operating conditions and must be strictly followed.

Environmental temperature derating: For VLT 3002-3008 (Chassis/NEMA 12), the output current needs to be reduced to 84% of the rated value at 45 ° C. For VLT 3060-3250 (CT mode, NEMA 1/12）， After exceeding 45 ° C, a 3% reduction in rating is required for every 1 ° C increase.

Altitude derating: After the altitude exceeds 3300 feet (1000 meters), for VLT 3060-3250 (CT mode), the output current needs to be derated by 5% for every 3300 feet increase at 45 ° C, or the maximum ambient temperature allowed to decrease by 3 ° C at full current.

Switching frequency derating: When the carrier frequency exceeds 4.5kHz, the maximum continuous output current linearly decreases, reaching only 60% of the rated value at 14kHz. Meanwhile, the length of motor cables should also be limited to within 130 feet (40 meters).

2. Suggestions for debugging process

Safe power-off and inspection: Confirm that the main power supply is disconnected, wait for the specified discharge time, and then perform wiring inspection.

Initialization and motor parameter setting: After power on, follow the "Quick Set up" process to set the language (parameter 000), motor nameplate parameters (103-105), and perform adaptive motor tuning (parameter 106) in sequence.

Basic functional configuration: Set minimum/maximum frequency (201/202) and acceleration/deceleration time (215/216).

Control logic wiring and parameterization: According to the process requirements, complete the control line wiring and configure the corresponding terminal functional parameters (400 series).

Protection and advanced function settings: Configure motor thermal protection (parameter 315), braking function (300 series) or PID parameters (1 set and appendix).

Communication configuration (if required): Set the address (500), baud rate (501), and bus logic parameters (503-510).

Trial operation and optimization: Under the premise of ensuring safety, conduct no-load and load trial operation, observe current, voltage, temperature, and adjust parameters (such as slip compensation and PID parameters) according to actual working conditions.