Lovato VT107A240 0.75 kW VT1 Variable Speed Drive

VT1 frequency inverter: 0.75 kW output from a single-phase mains

Variable speed from a single-phase supply is what the VT107A240 (VT1 series, 0.75 kW (1 HP), 4.3 A) provides; input 200-240VAC 50/60Hz, output 0-599 Hz. It lets a squirrel-cage motor accelerate and run at controlled speed.

Radio-frequency interference is handled by the built-in EMC suppressor cat. C2 inside the housing, and the serial port is RS485, Modbus-RTU and BACnet.

Overload capacity is 150% for 60s, with a switching frequency of 1-16kHz.

Technical specifications

What to check for rating and control

With 4.3 A available at the output, motors up to about 0.75 kW fit, but always confirm by nameplate current and duty (the overload figure is 150% for 60s). A mains choke reduces the input current figure of 11 A and is a common choice on weak supplies.

Control modes listed: V/f linear, V/f quadratic, V/f multi-point , sensorless vector control.

A brake chopper is not fitted and the safe-torque-off function is not provided.

Typical duties and mounting

Common applications include booster and circulation pumps, ventilation fans, conveyors and small process machines. On long motor cables an output filter or a different EMC category may be needed; the datasheet table of maximum cable length by category is the reference.

The housing is 72 x 141 x 141 mm and weighs 1 Kg, protection IP20. Mount it vertically with the clearances shown in the manual, keep the ambient within the stated range and derate the current above 1000 m altitude as the datasheet describes.

Wiring a single-phase VT1 installation

Feed the drive from a single-phase circuit protected as the Lovato manual specifies, and remember that the input current is much higher than the output current, so the supply cable and breaker are sized from the input figure, not the motor. The motor must be connected for three-phase operation at the drive output voltage; check the terminal box links on the motor before connecting. Use screened motor cable within the length limits of the EMC table, bond the screen to earth, and keep signal wiring for the analog inputs, digital inputs and RS485 line separate from the power wiring. If a PTC probe is fitted in the motor, wire it to the PTC input so the drive can protect the winding.

Commissioning steps

Enter the motor nameplate data, choose the control mode that suits the load, quadratic V/f for fans and centrifugal pumps or sensorless vector control for loads that need more torque at low speed, and run autotuning where the motor can be connected safely. Set acceleration and deceleration times with care: as there is no brake chopper, a short ramp on a high-inertia fan can cause overvoltage trips, so lengthen the ramp or use DC braking within its limits. If the drive is controlled over Modbus-RTU or BACnet, agree addresses and baud rate with the building or PLC integrator before start-up.

Cabinet conditions in Oman’s climate

Natural cooling means the VT1 depends entirely on the air around it, so ambient temperature matters even more than with fan-cooled drives. Above 40 °C the datasheet asks for current derating, and pump rooms, rooftop plant and outdoor boxes in the Gulf often pass that in summer. Allow the derating when choosing the drive, or improve ventilation or cooling of the enclosure. The IP20 housing and pollution degree 2 limit mean it must sit in a clean, closed enclosure on dusty sites, and in humid coastal buildings the enclosure should keep out moisture and condensation.

Keeping it in service

At routine visits, remove dust from the drive and enclosure, check that ventilation paths are open, and inspect terminals for heat marks. Review the fault history for overtemperature or overload events, which often reveal a cooling problem or a pump working against a blocked line. Keep a copy of the parameter settings so a replacement drive can be configured quickly.

Documents and quotation

The figures above are those printed in the manufacturer’s datasheet for VT107A240, supplied here as an attached English PDF from the Lovato catalogue. Ordering checklist: the motor nameplate current, the supply type and voltage, the EMC category needed for your cable lengths and whether a keypad or safe-torque-off option is required. Data in the datasheet is subject to change by the manufacturer. Other options are in ac drives. An RFQ for VT107A240 needs only the quantity and delivery location; Seven Star LLC, an independent Muscat supplier, replies with availability.