Inverter DLB1-03D7T4G DLB1-O3D7T4G DLB103D7T4G

DLB1-03D7T4G | Dorna VFD Inverter — 3.7kW / 380V 3-Phase / 10.5A Input / 8.5A Output / General Purpose AC Drive

Dorna DLB1 Series — General-Purpose Variable Frequency Drive

The DLB1-03D7T4G is Dorna's DLB1 series 3.7kW general-purpose variable frequency drive. The DLB1 is designed for straightforward AC motor speed control across a wide range of standard industrial applications — conveyor systems, fans, pumps, compressors, and machine tool auxiliary drives.

At 3.7kW from a standard three-phase 380V industrial supply, the DLB1-03D7T4G controls induction motors in the mid-range of industrial motor power — a practical size for conveyor drives, air handling fans, centrifugal pump speed control, and production machine auxiliary drives.

Key Specifications

General Purpose — Wide Application Range

The DLB1-03D7T4G is a general-purpose VFD — not application-specific. "General purpose" means the drive is designed and configured for the broadest range of standard AC motor applications:

V/Hz control: Provides basic variable speed control suitable for fan, pump, and conveyor applications where dynamic speed accuracy is not required.

Sensorless vector control (if equipped): Where available in the DLB1 firmware, vector control improves low-speed torque and speed accuracy — extending the drive's applicability to applications requiring better motor performance at speeds below 15Hz.

Application Scenarios

Conveyor drive: A production conveyor requires variable-speed control of its 3.7kW drive motor. DLB1-03D7T4G provides smooth speed ramp up and down, protecting the conveyor from mechanical shock during start and stop cycles — without the high starting current of a direct-on-line motor start.

Cooling fan speed control: An industrial cooling fan driven by a 3.7kW motor requires variable speed to match cooling capacity to heat load. DLB1-03D7T4G reduces fan speed during low-load periods — reducing noise and saving energy compared to fixed-speed operation.

FAQ

Q1: What type of AC motor is compatible with DLB1-03D7T4G?

DLB1-03D7T4G drives standard three-phase AC induction motors rated at 3.7kW and 380V. The motor must match the drive's rated output voltage (380V three-phase) and current (8.5A maximum). Motors with nameplate current above 8.5A should not be connected. Ensure the motor's rated voltage matches the drive's output voltage class.

Q2: Does DLB1-03D7T4G have a built-in braking resistor connection?

General-purpose VFDs in the DLB1 class typically provide a braking resistor connection terminal but do not include the braking resistor itself. An external braking resistor connected to the DC bus resistor terminals enables dynamic braking — allowing the drive to decelerate loads quickly by dissipating regenerated energy in the resistor rather than allowing the DC bus voltage to rise. Confirm from the DLB1 installation manual whether a braking resistor terminal is available and the minimum resistance specification for 3.7kW.

Q3: What output frequency range does DLB1-03D7T4G support?

The DLB1 series drives in this class typically support output frequency ranges from 0Hz (motor standstill) to 400Hz or 650Hz maximum — well beyond the 50/60Hz base frequency. Above 50Hz, the motor speed exceeds its nameplate rated speed (the drive operates in the "field weakening" region) — useful for driving high-speed spindles or fans where above-rated speed is required. Confirm the specific maximum output frequency from the DLB1-03D7T4G product documentation.

Q4: What protection functions does DLB1-03D7T4G provide for the connected motor?

Dorna DLB1 drives incorporate standard VFD protection functions: overcurrent protection (detecting motor or wiring faults at above-rated current), overvoltage and undervoltage protection (shutting down if the supply voltage is outside acceptable limits), electronic motor overload protection (detecting sustained overcurrent that indicates motor overload — adjustable for the specific motor's rated current), and output phase loss detection. These protections reduce the need for separate overload relays and current protection devices on the motor circuit.