This document describes the Motortronics MVC Plus series medium voltage solid-state soft starter, a motor controller designed for starting, protecting, and controlling medium voltage AC induction and synchronous motors. It incorporates SCR power units, fiber optic communication, and low voltage control circuits.
Function Description:
The MVC Plus soft starter provides comprehensive motor protection and control through four operational modes: start preparation, start, run, and stop. It offers various starting methods, including voltage ramp, current ramp, and custom acceleration curves, to ensure smooth motor acceleration and minimize mechanical and electrical stress. The soft starter also features a "Soft Stop" (pump control) function to gradually reduce output voltage and torque, preventing water hammer in pump applications and sudden stops in conveyor systems.
Important Technical Specifications:
- Load Types: Three-phase medium voltage asynchronous motors, synchronous motors.
- Voltage Range: 1000-13800VAC +10%-15%.
- Overload Capacity (as % of rated current): 125% continuous operation, 500% for 60 seconds, 600% for 30 seconds, 14 times for 1 cycle (set by internal short-circuit protection).
- Frequency Range: 50Hz/60Hz ±2Hz (hardware configurable).
- Main Circuit Components: 6, 12, 18, or 36 SCRs (model dependent).
- SCR Reverse Peak Voltage: 4500V-39000V (model dependent).
- Phase Sequence: MVC allows operation in any phase sequence.
- Instantaneous Overvoltage Protection: dv/dt absorption network, overvoltage protector (optional).
- Control Power: User-provided 220VAC, capacity not less than 1.5kVA.
- Relay Outputs: Multiple outputs, C-type dry contacts, max 5A 240VAC (8 programmable relays).
- Insulation Level: 30kV for 1000V, 60kV for 2300V-7200V, 110kV for 10000V-13800V.
- Certifications: UL (USA), cUL (Canada), CE (Europe).
- Overload Curves: Programmable from 5 to 30 levels during start and full-speed operation.
- Overload Reset: Manual.
- Thermal Capacity: Overload protection circuit's thermal capacity value is independent of control power; internal real-time clock automatically adjusts.
- Phase Current Imbalance Protection: Range 5-30% (any two phases), trip time 1-20 seconds.
- Overcurrent Protection: Range 100-300%FLA (effective during operation), trip time 1-20 seconds.
- Underload Protection: Trip value 10-90% FLA, trip time 1-60 seconds.
- Coast (Anti-reverse) Timer: 1-60 minutes or disabled.
- Starts per Hour: 1-6 starts per hour or disabled.
- Start Interval: 1-60 minutes or disabled.
- Ramp Types: Programmable voltage ramp (VR) or current ramp (CR).
- Start Torque: 0-100% line voltage (VR) or 0-300% motor rated current (CR).
- Ramp Time: 1-120 seconds.
- Current Limit: 200-500% (VR or CR).
- Power Ramp: 0-300%.
- Dual Ramp: Four combinations (VR1+VR2; VR1+CR2; CR1+VR2; CR1+CR2).
- Soft Stop Voltage: 80-100% line voltage (start), 0-(start soft stop voltage-1%) (stop).
- Soft Stop Time: 1-60 seconds.
- Jog Voltage: 5-75%.
- Kick Start Voltage: 10-100%.
- Kick Start Time: 0.1-2 seconds.
- Fault Display: SCR short circuit, phase loss, phase imbalance, overload, overtemperature, overcurrent, short circuit, underload, undervoltage, or any other trip.
- Event Log: Up to 60 events, including cause, time, date, phase voltage/current, power factor, zero sequence current (optional).
- Communication Protocol: Modbus RTU.
- Communication Interface: RS-485, RS-422, or RS-232.
- Network Connection: Each MVC can connect to up to 247 MVC devices.
- Display: LCD (liquid crystal display).
- Keypad: 8 touch keys.
- Status Display: 12 high-brightness LED indicators (Power, Run, Alarm, Trip, Auxiliary Relays).
- Remote Installation: Control keypad can be up to 300 meters away from MVC (using shielded twisted pair and external power).
- Memory: SRAM downloads data from F-RAM during power-up initialization. Internal flash memory. Non-volatile F-RAM, no battery required for memory. Real-time clock powered by lithium battery.
Usage Features:
- Comprehensive Protection: Built-in motor protection for overload, phase imbalance, short circuit, overcurrent, RTD overtemperature, ground fault, undervoltage, overvoltage, power factor, and more.
- Flexible Starting Modes: Supports voltage ramp, current ramp, dual ramp, and custom acceleration curves to adapt to various load characteristics and application requirements.
- Soft Stop (Pump Control): Gradually reduces motor output voltage to prevent water hammer and mechanical shock during shutdown.
- User-Friendly Interface: LCD display and keypad for easy parameter setting, monitoring, and fault diagnosis.
- Programmable Relays: 8 programmable auxiliary relays for flexible control and signaling.
- RTD Monitoring (Optional): Supports up to 12 RTD inputs for precise motor temperature monitoring and protection.
- Event Recording: Stores up to 60 events with detailed information for troubleshooting and analysis.
- Statistical Data: Provides comprehensive statistical data, including total energy consumption, running time, and trip counts for various fault types.
- Communication Capabilities: Modbus RTU interface for remote monitoring, control, and parameter adjustment.
- Self-Learning Function: Can learn motor starting characteristics and create custom protection curves.
- Power Factor Control: Monitors and protects against leading or lagging power factor conditions.
Maintenance Features:
- Designed for Low Maintenance: The soft starter is designed to be maintenance-free, but regular inspections are recommended to check for dust, moisture, or other industrial contaminants.
- Troubleshooting Guide: The manual provides a detailed troubleshooting section with common fault symptoms, possible causes, and corrective actions.
- LED Indicators: Multiple LED indicators provide quick visual status of power, run, alarm, and trip conditions.
- LCD Fault Display: Displays detailed fault messages to assist in rapid diagnosis.
- Diagnostic Tests: Includes a procedure for testing SCRs and heatsink resistance.
- Thermal Register: Monitors and stores thermal capacity data, aiding in understanding motor heating and cooling characteristics.
- Cooling Fan Inspection: If the device is installed in a dirty environment and uses fan cooling, regular inspection and cleaning of the cooling fans are essential.
- Bolt Tightening: Annual inspection of bolts for tightness using a torque wrench is recommended.
- Vacuum Contactor Inspection: Inspect vacuum contactor air gap according to manufacturer's specifications.
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