Open-Loop Single-Phase 220V Elevator Frequency Inverter with SVC

Product Overview

The SD310L is an open-loop elevator frequency inverter developed for lift systems using a single-phase 220V power supply. It provides Sensorless Vector Control and V/F control for managing motor speed, torque, acceleration, and deceleration without requiring encoder feedback in SVC mode.

The drive combines overload capability, multi-step speed settings, programmable I/O, automatic voltage regulation, motor parameter identification, and multiple fault protections in one platform. It can be integrated with a compatible elevator controller for residential lifts, low-rise passenger elevators, cargo lifts, and selected retrofit projects.

As an open-loop drive, the SD310L is intended for applications where its speed accuracy, starting torque, motor compatibility, and control method satisfy the actual elevator design requirements.

Open-Loop SVC Control

Encoder-Free Motor Control

Sensorless Vector Control estimates motor operating conditions through the drive’s internal motor model. It does not require an encoder to provide continuous speed feedback.

Removing the encoder can simplify wiring and reduce the number of feedback components in an elevator drive system. Correct motor data and commissioning remain essential because SVC performance depends on the accuracy of the motor model.

Low-Speed Torque

In SVC mode, the SD310L provides 150% of rated starting torque at 0.5Hz. This supports controlled motor startup in compatible elevator systems where adequate low-speed torque is required.

Starting performance also depends on motor selection, load balance, brake timing, acceleration settings, and mechanical conditions. The drive rating should therefore be selected using motor current and duty requirements rather than motor power alone.

Speed Regulation

The SVC speed adjustment range is 1:100, with published speed accuracy of ±0.5% of maximum speed. This level of control suits lift applications that do not require encoder-based positioning or zero-speed holding.

For high-speed elevators, high-rise projects, rapidly changing loads, or systems requiring more precise floor leveling, a closed-loop drive should be evaluated.

Elevator Motion Control

Adjustable Speed References

The SD310L accepts speed and frequency commands from several sources:

• Built-in keypad

• Analog input

• Serial communication

• Multi-step speed settings

• PID control

• Combined command modes

This allows the drive to work with different elevator controller signal arrangements.

Eight-Step Speed Control

Up to eight speed steps can be configured for startup, normal travel, inspection, leveling, or other operating stages defined by the elevator controller.

Each speed stage should be coordinated with the acceleration and deceleration settings. Incorrect transitions may affect ride comfort, stopping distance, and system response.

Torque Control

Multiple torque-reference sources are available for applications that require adjustable torque limits. Torque-related parameters should be configured using the elevator load, motor data, traction system, and brake sequence.

Speed Tracking

The speed-tracking function can identify a rotating motor and support a controlled restart. Its use in an elevator system must be coordinated with the controller logic and applicable safety sequence.

Automatic Voltage Regulation

Automatic Voltage Regulation helps maintain a more stable output voltage when the incoming power supply fluctuates within the drive’s permitted operating range.

AVR does not replace suitable input protection or compensate for a supply that falls outside the inverter’s specified voltage and frequency limits.

Setup and Commissioning

Enter the Motor Data

Before operation, the technician should enter the motor’s rated voltage, current, frequency, speed, and power. These values should come directly from the motor nameplate or manufacturer documentation.

Run Motor Identification

The motor identification function allows the drive to establish the electrical parameters required by the SVC model. The elevator must be placed in a safe commissioning condition before this process begins.

Configure the Motion Profile

Acceleration, deceleration, inspection speed, travel speed, leveling speed, and stop behavior should be configured around the mechanical system and elevator controller.

A gradual commissioning process is recommended:

1. Verify motor and power wiring.

2. Confirm input and output assignments.

3. Test motor direction at low speed.

4. Check brake opening and closing sequence.

5. Test inspection operation.

6. Confirm acceleration and deceleration.

7. Test normal operation under controlled load.

8. Review fault records and operating current.

Verify the Brake Sequence

The drive controls motor output but does not replace the elevator’s mechanical brake or safety controller. Brake release and closing signals must follow the required motor torque and elevator controller sequence.

The car should not be placed into passenger operation until brake timing, travel direction, leveling behavior, emergency stop, and all external safety circuits have been tested.

I/O and Communication

The SD310L provides configurable inputs and outputs for connection to an elevator controller and related control devices.

The programmable terminals can be assigned to functions such as run commands, direction selection, multi-step speed, fault reset, operating status, or fault indication according to the system design.

Terminal definitions, signal voltage, grounding, shielding, and communication parameters should be verified during control-panel design.

Drive Protection

The SD310L provides multiple drive-level protections for detecting abnormal electrical and thermal conditions.

Protection functions include:

• Overcurrent protection

• Overvoltage protection

• Undervoltage protection

• Overload protection

• Overtemperature protection

• Phase-loss detection

• Additional drive and motor fault monitoring

When a fault occurs, the technician should identify and correct the cause before resetting the drive. Repeated resets without diagnosis may expose the motor, inverter, or mechanical system to further damage.

Role in the Elevator System

The frequency inverter manages motor speed and torque. It does not replace the elevator controller or any code-required safety device.

A complete elevator system may also require:

• Mechanical brake control

• Overspeed governor

• Safety gear

• Door interlocks

• Terminal and final limit switches

• Emergency stop circuit

• Load monitoring

• Inspection controls

• Emergency rescue equipment

• Other devices required by local elevator regulations

All safety circuits must remain effective independently of normal drive operation.

Elevator Applications

Residential and Villa Lifts

The single-phase 220V supply configuration can suit residential and villa lift projects where three-phase utility power is unavailable. Motor current, lift capacity, travel speed, number of floors, and starting conditions must be checked before selection.

Low-Rise Passenger Elevators

The SD310L can be considered for low-rise passenger elevator systems where open-loop SVC provides sufficient speed control and torque performance.

The final design should be approved by the elevator system integrator and tested for leveling, braking, load variation, and passenger operation.

Cargo Lifts

Cargo lift applications may use open-loop control when the load pattern, motor, brake system, and required positioning accuracy are compatible with the drive.

Heavy or rapidly changing loads require a separate torque and overload assessment.

Elevator Retrofit Projects

The inverter may be used when upgrading a compatible 220V lift control system. Before replacement, compare the original drive’s power supply, motor output, rated current, braking arrangement, I/O logic, communication method, and installation dimensions.

Replacing an existing inverter should not be treated as a direct one-for-one substitution until these parameters have been checked.

Technical Specifications

Quality and Engineering Support

IFIND applies an ISO 9001 quality management system and reports CE certification and BV field verification completed in 2024. Drives are assembled and tested before packing to check basic electrical and operating performance.

Technical support is available for:

• Drive model selection

• Motor data matching

• Parameter configuration

• I/O assignment

• Modbus communication

• Fault diagnosis

• Application-specific setup

For project evaluation, customers can request the applicable product datasheet, installation manual, wiring information, certificate documents, and configuration details.

FAQs

Does SVC operation require an encoder?

No. Sensorless Vector Control estimates motor speed and operating conditions without encoder feedback. Motor nameplate data and identification must be entered correctly for the control model to work as intended.

What is the difference between open-loop and closed-loop elevator control?

Open-loop control does not use continuous encoder feedback. It offers simpler wiring and lower system complexity but provides less low-speed and positioning accuracy than closed-loop control. Closed-loop control is normally evaluated for high-speed, high-rise, heavy-duty, or precise-leveling applications.

Can the SD310L work with any 220V elevator motor?

No. Compatibility depends on the motor type, rated voltage, phase, current, power, frequency, speed, insulation, and control requirements. The motor nameplate and elevator specifications should be reviewed before selecting the drive.

How should the inverter power rating be selected?

Selection should consider the motor’s rated current, required starting torque, overload duty, lift capacity, travel speed, counterweight ratio, acceleration time, and operating frequency. A drive should not be selected only by comparing its kW rating with the motor kW.

Does the inverter replace the elevator controller?

No. The inverter controls motor speed and torque. The elevator controller manages travel commands, floor logic, door operation, safety sequence, brake commands, fault handling, and other system functions.

What information is needed before commissioning?

Prepare the motor nameplate data, elevator rated load, travel speed, traction or lifting arrangement, controller signal definition, brake sequence, required speed stages, I/O list, and communication settings.

Does the inverter support Modbus communication?

Yes, Modbus communication is supported when the optional RS485 interface is included. Confirm the hardware configuration, baud rate, address, parity, register map, and communication wiring before integration.

What should be checked when replacing an existing elevator drive?

Compare the input supply, motor output, rated current, overload rating, braking configuration, control terminals, analog signal ranges, communication protocol, mounting dimensions, and required safety functions.

Can the drive be used for both passenger and cargo lifts?

It may be used in compatible passenger or cargo lift systems when open-loop control meets the required load, speed, torque, leveling, and safety conditions. Final suitability must be assessed by the elevator system integrator.

What happens when the drive reports an overcurrent fault?

Check motor wiring, motor parameters, brake timing, acceleration settings, mechanical resistance, load condition, and drive capacity. The fault should not be repeatedly reset until its cause has been identified.