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Covers High Voltage, Unintended Start, and Damage Avoidance.
Overview of MCD 201 and MCD 202 ranges and their features.
Continuous current ratings for MCD 200 models at different temperatures.
Recommended semiconductor fuses for MCD 200 soft starters.
Wiring for control circuits and user-adjustable functionality parameters.
LED indicators and troubleshooting guide for MCD 201.
MCD 202 overview, function, and wiring diagrams.
Wiring diagrams for 2-wire control for MCD 202.
Key adjustable parameters for MCD 202 functionality.
The Danfoss MCD 200 series of soft starters is designed to provide controlled starting and stopping of AC induction motors, offering a range of functionalities to suit various application needs. The series includes two main ranges: the MCD 201 and the MCD 202, which share a common power and mechanical design but differ in their operational capabilities.
The primary function of the MCD 200 series is to provide a soft start for motors, which involves gradually increasing the voltage supplied to the motor during startup. This process reduces the initial inrush current and mechanical stress on the motor and connected equipment, leading to smoother operation and extended equipment life.
The MCD 201 soft starters offer Timed Voltage Ramp (TVR) control for both starting and stopping. This means the voltage is ramped up or down over a preset time, allowing for a controlled acceleration and deceleration of the motor. The MCD 201 is designed to be used in conjunction with an external motor protection device, as it does not include built-in motor protection functions.
The MCD 202 soft starters, on the other hand, provide more advanced control with Current Limit starting. This mode allows the user to set a maximum starting current, and the soft starter adjusts the voltage to ensure the motor accelerates within this limit. The MCD 202 also includes TVR soft stop functionality and a comprehensive suite of built-in motor protection functions, eliminating the need for an external motor protection device in many applications.
Both MCD 201 and MCD 202 models incorporate an integral bypass function. During normal run operation, the soft starter's Silicon Controlled Rectifiers (SCRs) are bypassed. This feature minimizes heat dissipation, making the MCD 200 suitable for installation in non-ventilated enclosures without requiring an external bypass contactor. This internal bypass helps to reduce energy losses and prolong the life of the SCRs by protecting them from overcurrent or overvoltage events that might occur during continuous running.
The MCD 202's programmable output relay offers versatile functionality, allowing it to be configured as a "Trip" output or a "Run" output. When set to "Trip," the relay activates if the MCD 202 detects a fault, which can be used to signal an automation system or trigger an upstream circuit breaker. When set to "Run," the relay activates upon completion of the start ramp, which can be used to control power factor correction capacitors or provide a "Run" status signal.
The MCD 200 series offers user-friendly adjustments to optimize motor performance for specific applications. For the MCD 201, users can set the "Initial Torque" to determine the starting torque, ensuring the motor begins to rotate as soon as the start command is given. The "Ramp Up" time can be adjusted to control the acceleration, balancing quicker acceleration with lower start currents. The "Ramp Down" time allows for a controlled deceleration, extending the motor's stopping time to reduce mechanical shock.
The MCD 202 provides more granular control with features like "Current Limit," which sets the maximum starting current, ensuring the motor accelerates smoothly without excessive current draw. The "Current Ramp" mode modifies the Current Limit start by adding an extended ramp, which is particularly useful for applications where start conditions vary, such as conveyors that may start loaded or unloaded. This ensures an optimum soft start regardless of the motor loading.
The MCD 202 also includes "Motor FLC" calibration to match the soft starter to the motor's full load current, enhancing the accuracy of its protection functions. "Excess Start Time Protection" allows users to set a maximum allowable start time, tripping the soft starter if the motor takes too long to accelerate, indicating a potential issue or stall. "Phase Rotation Protection" can be configured to allow or restrict motor operation based on the incoming supply's phase sequence, preventing damage from reverse rotation in sensitive applications.
Both MCD 201 and MCD 202 models support 2-wire and 3-wire control configurations, offering flexibility in integration with various control systems. The control inputs for start and stop commands are designed for reliability and can be connected to external control devices.
For enhanced control and monitoring, the MCD 200 series supports several accessory modules. The Remote Operator provides pushbutton control (Start, Stop, Reset), displays starter status (Starting, Running, Tripped), motor current, motor temperature, and trip codes, and offers a 4-20 mA analog output for motor current. Communication modules like Modbus, Profibus, and DeviceNet allow for integration into industrial networks, enabling remote control and monitoring of multiple soft starters. The MCD PC Software further extends these capabilities, allowing operational control, status monitoring, performance monitoring, and parameter management for networks of up to 99 soft starters.
The MCD 200 series is also designed to handle "flying start" applications, with a built-in 2-second delay between stop and start commands to allow motor flux to decay, preventing nuisance trips on power circuit faults. This ensures reliable operation even when the motor is restarted quickly.
The MCD 200 series is designed for reliability and ease of maintenance. The integral bypass function minimizes heat dissipation during run, reducing stress on the SCRs and contributing to a longer lifespan for the soft starter. This design choice also means less wear and tear on components, as the SCRs are only active during starting and soft stopping.
The MCD 202's built-in electronic "thermal model" motor overload protection continuously monitors motor current and calculates the expected motor temperature. This feature helps prevent motor damage due to overheating and provides an early warning of potential issues. The Motor Trip Class setting allows users to calibrate the thermal model according to the motor's specific thermal characteristics, ensuring accurate protection. If an overload occurs, the soft starter will trip, and it cannot be reset until the motor has cooled adequately, preventing immediate restart into a potentially damaging condition.
Fault finding is facilitated by clear LED indications on the soft starter. Different flash patterns of the "Ready" LED correspond to specific fault conditions, such as power circuit faults, supply frequency issues, network communication failures, or starter communication failures. This visual feedback helps maintenance personnel quickly diagnose and address problems. For instance, a "Ready" LED flashing once indicates a power circuit fault, prompting checks of mains supply, motor circuits, and SCRs. Multiple flashes indicate other issues, guiding troubleshooting efforts.
The modular design, with plug-in accessory items, simplifies installation and replacement of control and communication modules. However, it is crucial to remove control power and mains supply before attaching or removing any accessory modules to prevent equipment damage and ensure safety.
The MCD 200 series is built to withstand various environmental conditions, with different degrees of protection (IP20 or IP00) depending on the model, and an operating temperature range of 10 °C to +60 °C. The robust design and comprehensive protection features contribute to the overall reliability and reduced maintenance requirements of the soft starters.
General| Rated control supply voltage Us | 24 V AC/DC |
|---|---|
| IP Rating | IP20 |
| Frequency | 50/60 Hz |
| Protection functions | Phase loss |
| Communication | Modbus RTU |
| Storage Temperature | +70 °C |
| Relative Humidity | 5 - 95% (non-condensing) |
