VLT Micro Drive FC 51 Operating Guide
Brand: Danfoss
1 Introduction
This Operating Guide provides necessary information for qualified personnel to install and commission the AC drive. Read and follow the instructions to use the drive safely and professionally. VLT® is a registered trademark for Danfoss A/S.
Do not dispose of equipment containing electrical components together with domestic waste. Collect it separately in accordance with local and currently valid legislation.
2 Safety
WARNING HIGH VOLTAGE AC drives contain high voltage when connected to AC mains input, DC supply, or load sharing.
UNINTENDED START The motor may start from LCP, I/O inputs, fieldbus, or MCT 10 Set-up software at any time, when the drive is connected to the AC mains, DC supply, or load sharing.
DISCHARGE TIME The drive contains DC-link capacitors, which can remain charged even when the drive is not powered. High voltage can be present even when the warning indicator lights are off. - Stop the motor, and disconnect AC mains, permanent magnet type motors, and remote DC-link supplies, including battery back-ups, UPS, and DC-link connections to other drives. - Wait for the capacitors to discharge fully and measure it before performing any service or repair work. - The minimum waiting time is 4 minutes for M1, M2, and M3 drives, and 15 minutes for M4 and M5 drives.
LEAKAGE CURRENT Leakage currents of the drive exceed 3.5 mA. Make sure that the drive is properly grounded with at least 10 mm² (8 AWG) grounding wire and use RCDs of type B with an inrush delay.
3 Installation
3.1 Mechanical Dimensions
| Enclosure size | Height [mm (in)] | Width [mm (in)] | Depth [mm (in)] | Mounting holes [mm (in)](2) | Maximum weight [kg (lb)] |
| M1 | 150 (5.9) | 205 (8.1) | 140.4 (5.5) | 70 (2.8) | 1.1 (2.4) |
| M2 | 176 (6.9) | 230 (9.1) | 166.4 (6.6) | 75 (3.0) | 1.6 (3.5) |
| M3 | 239 (9.4) | 294 (11.6) | 226 (8.9) | 90 (3.5) | 3.0 (6.6) |
| M4 | 292 (11.5) | 347.5 (13.7) | 272.4 (10.7) | 125 (4.9) | 6.0 (13.2) |
| M5 | 335 (13.2) | 387.5 (15.3) | 315 (12.4) | 165 (6.5) | 9.5 (20.9) |
(1) Including decoupling plate. (2) For LCP with potentiometer, add 7.6 mm (0.3 in).
3.2 Connecting to Mains and Motor
- Mount the ground wires to the PE terminal.
- Connect motor to terminals U, V, and W.
- Mount mains supply to terminals L1/L, L2, and L3/N (3-phase) or L1/L and L3/N (single-phase) and tighten.
3.3 Load Sharing/Brake
Use 6.3 mm (0.25 in) insulated Faston plugs designed for high voltage for DC (load sharing and brake). Contact Danfoss or see Load sharing instruction VLT® 5000 for load sharing and VLT® 2800/5000/5000 FLUX/FCD 300 Brake for brake.
Load sharing: Connect terminals -UDC and +UDC/+BR. Brake: Connect terminals -BR and +UDC/+BR (not applicable to enclosure size M1).
NOTICE: Voltage levels of up to 850 V DC may occur between terminals +UDC/+BR and -UDC. Not short-circuit protected.
3.4 Control Terminals
All control cable terminals are located underneath the terminal cover in front of the drive. Remove the terminal cover using a screwdriver.
NOTICE: - See the back of the terminal cover for outlines of control terminals and switches. - Do not operate switches with power on the drive. - Set parameter 6-19 Terminal 53 Mode according to Switch 4 position.
S200 Switches Configuration
Switch 1: Controls PNP/NPN terminal configuration for terminal 29. Off = PNP, On = NPN.
Switch 2: Controls PNP/NPN terminal configuration for terminals 18, 19, 27, and 33. Off = PNP, On = NPN.
Switch 3: No function.
Switch 4: Selects analog input mode for terminal 53. Off = 0-10 V, On = 0/4-20 mA. (Default setting is Off).
Control Terminal Overview
The following illustration shows all control terminals of the drive. Applying start (terminal 18) and an analog reference (terminal 53 or 60) make the drive run. The overview shows terminal numbers (61, 68, 69, 12, 18, 19, 20, 27, 29, 33, 42, 50, 53, 55, 60) and their functions, such as +24V, GND, Analog Inputs (A IN), Analog Outputs (A OUT), Digital Inputs (D IN), and RS485 communication. The diagram shows factory settings for PNP configuration.
4 Programming
4.1 Local Control Panel (LCP)
The Local Control Panel (LCP) features a numeric display, indicator lights for status (On, Warn, Alarm), and control keys. Navigation keys include [Menu], [Back], and directional arrows. Confirmation is done with [OK]. Operation keys are [Hand On] for manual start, [Off/Reset] for stopping or resetting alarms, and [Auto On] for automatic control. An LCP12 model includes a potentiometer for manual control.
4.2 Programming on Automatic Motor Tuning (AMT)
Run AMT to optimize compatibility between the drive and the motor in VVC+ mode. The drive builds a mathematical model of the motor for regulating output motor current thus enhancing motor performance. 1. Enter the main menu. 2. Set parameter group 1-** Load and Motor, parameter group 1-2* Motor Data, and parameter 1-29 Automatic Motor Tuning (AMT). 3. Press [OK]. The test runs automatically and indicates when it is complete.
5 Parameter Overview
This section lists the parameter groups and individual parameters available for configuring the VLT Micro Drive FC 51. Parameters are organized into logical groups such as Operation/Display, Set-up Operations, Load and Motor, References/Ramps, Limits/Warnings, Digital In/Out, Brakes, Comm. and Options, Smart Logic, Data Readouts, and Drive Information.
6 Troubleshooting
This table lists common warnings, alarms, and triplock errors, along with their potential causes and recommended actions.
| Number | Description | Warning | Alarm | Triplock | Error | Cause of problem |
| 2 | Live zero error | X | X | Signal on terminal 53 or 54 is less than 50% of the value set in: Parameter 6-10 Terminal 53 Low Voltage, Parameter 6-12 Terminal 53 Low Current, or Parameter 6-22 Terminal 54 Low Current. | ||
| 4 | Mains phase loss(1) | X | X | X | Missing phase on the supply side or too high voltage imbalance. Check the supply voltage. | |
| 7 | DC overvoltage(1) | X | X | X | DC-link voltage exceeds the limit. | |
| 8 | DC undervoltage(1) | X | X | X | DC-link voltage drops below voltage warning low limit. | |
| 9 | Inverter overload | X | X | X | More than 100% load for a long time. | |
| 10 | Motor ETR overtemperature | X | X | X | Motor is too hot due to more than 100% load for a long time. | |
| 11 | Motor thermistor overtemperature | X | X | X | Thermistor or thermistor connection is disconnected. | |
| 12 | Torque limit | X | X | Torque exceeds value set in either parameter 4-16 Torque Limit Motor Mode or parameter 4-17 Torque Limit Generator Mode. | ||
| 13 | Overcurrent | X | X | X | Inverter peak current limit is exceeded. | |
| 14 | Ground fault | X | X | X | Discharge from output phases to ground. | |
| 16 | Short circuit | X | X | X | Short circuit in motor or on motor terminals. | |
| 17 | Control word timeout | X | X | X | No communication to drive. | |
| 25 | Brake resistor short-circuited | X | X | X | Brake resistor is short-circuited, thus the brake function is disconnected. | |
| 27 | Brake chopper short-circuited | X | X | X | Brake transistor is short-circuited, thus the brake function is disconnected. | |
| 28 | Brake check | X | X | Brake resistor is not connected/working. | ||
| 29 | Power board over temp | X | X | X | Heat sink cutout temperature has been reached. | |
| 30 | Motor phase U missing | X | X | X | Motor phase U is missing. Check the phase. | |
| 31 | Motor phase V missing | X | X | X | Motor phase V is missing. Check the phase. | |
| 32 | Motor phase W missing | X | X | X | Motor phase W is missing. Check the phase. | |
| 38 | Internal fault | X | X | X | Contact the local Danfoss supplier. | |
| 47 | Control voltage fault | X | X | X | 24 V DC supply is overloaded. | |
| 51 | AMA check Unom and Inom | X | X | Wrong setting for motor voltage and/or motor current. | ||
| 52 | AMA low Inom | X | X | The motor current is too low. Check the settings. | ||
| 59 | Current limit | X | X | The drive is overloaded. | ||
| 63 | Mechanical brake low | X | X | Actual motor current has not exceeded the release brake current within the start delay time window. | ||
| 80 | Drive initialized to default value | X | X | All parameter settings are initialized to default settings. | ||
| 84 | The connection between drive and LCP is lost | X | No communication between LCP and drive. | |||
| 85 | Key disabled | X | See parameter group 0-4* LCP. | |||
| 86 | Copy fail | X | An error occurred while copying from drive to LCP, or from LCP to drive. | |||
| 87 | LCP data invalid | X | Occurs when copying from LCP if the LCP contains erroneous data - or if no data was uploaded to the LCP. | |||
| 88 | LCP data not compatible | X | Occurs when copying from LCP if data is moved between drives with major differences in software versions. | |||
| 89 | Parameter read only | X | Occurs when trying to write to a read-only parameter. | |||
| 90 | Parameter database busy | X | LCP and RS485 connections are trying to update parameters simultaneously. | |||
| 91 | Parameter value is not valid in this mode | X | Occurs when trying to write an illegal value to a parameter. | |||
| 92 | Parameter value exceeds the min/max limits | X | Occurs when trying to set a value outside the range. | |||
| nw run | Not while running | X | Parameters can only be changed when the motor is stopped. | |||
| Err. | A wrong password was entered | X | Occurs when using a wrong password for changing a password-protected parameter. |
(1) These faults are caused by mains distortions. Install a Danfoss line filter to rectify this problem.
7 Specifications
Table 2: Mains Supply 1x200 240 V AC
| Drive | Typical shaft output [kW (hp)] | Enclosure protection rating IP20 | Output current Continuous (3x200 240 V) [A] | Intermittent (3x200 240 V) [A] | Maximum cable size (Mains, motor) [mm/AWG] | Maximum input current Continuous (1x200 240 V) [A] | Intermittent (1x200 240 V) [A] | Environment Estimated power loss [W], Best case/typical(1) |
| PK18 | 0.18 (0.25) | M1 | 1.2 | 1.8 | 3.3 | 4.5 | 12.5/15.5 | |
| PK37 | 0.37 (0.5) | M1 | 2.2 | 3.3 | 6.1 | 8.3 | 20/25 | |
| PK75 | 0.75 (1) | M1 | 4.2 | 6.3 | 11.6 | 15.6 | 36.5/44 | |
| P1K5 | 1.5 (2) | M2 | 6.8 | 10.2 | 18.7 | 26.4 | 61/67 | |
| P2K2 | 2.2 (3) | M3 | 9.6 | 14.4 | 26.4 | 37 | 81/85.1 |
Normal overload 150% for 1 minute
Table 3: Mains Supply 3x200 240 V AC
| Drive | Typical shaft output [kW (hp)] | Enclosure protection rating IP20 | Output current Continuous (3x200 240 V) [A] | Intermittent (3x200 240 V) [A] | Maximum cable size (Mains, motor) [mm/AWG] | Maximum input current Continuous (3x200 240 V) [A] | Intermittent (3x200 240 V) [A] | Environment Estimated power loss [W], Best case/typical(1) |
| PK25 | 0.25 (0.33) | M1 | 1.5 | 2.3 | 2.4 | 3.2 | 14/20 | |
| PK37 | 0.37 (0.5) | M1 | 2.2 | 3.3 | 3.5 | 4.6 | 19/24 | |
| PK75 | 0.75 (1) | M1 | 4.2 | 6.3 | 6.7 | 10.9 | 4/10 | |
| P1K5 | 1.5 (2) | M2 | 6.8 | 10.2 | 10.9 | 14.4 | 31.5/39.5 | |
| P2K2 | 2.2 (3) | M3 | 9.6 | 14.4 | 15.4 | 24.3 | 51/57 | |
| P3K7 | 3.7 (5) | M3 | 15.2 | 22.8 | 23.4 | 35.3 | 72/77.1 |
Normal overload 150% for 1 minute
Table 4: Mains Supply 3x380 480 V AC
| Drive | Typical shaft output [kW (hp)] | Enclosure protection rating IP20 | Output current Continuous (3x380 440 V) [A] | Intermittent (3x380 440 V) [A] | Continuous (3x440 480 V) [A] | Intermittent (3x440 480 V) [A] | Maximum cable size (Mains, motor) [mm/AWG] | Maximum input current Continuous (3x380 440 V) [A] | Intermittent (3x380 440 V) [A] | Continuous (3x440 480 V) [A] | Intermittent (3x440 480 V) [A] | Environment Estimated power loss [W], Best case/typical(1) |
| PK37 | 0.37 (0.5) | M1 | 1.2 | 1.8 | 1.1 | 1.7 | 4/10 | 1.9 | 2.6 | 1.7 | 2.3 | 18.5/25.5 |
| PK75 | 0.75 (1) | M1 | 2.2 | 3.3 | 2.1 | 3.2 | 3.5 | 4.7 | 3.0 | 4.0 | 28.5/43.5 | |
| P1K5 | 1.5 (2) | M2 | 3.7 | 5.6 | 3.4 | 5.1 | 5.9 | 8.7 | 5.1 | 7.5 | 41.5/56.5 | |
| P2K2 | 2.2 (3) | M2 | 5.3 | 8.0 | 4.8 | 7.2 | 8.5 | 12.6 | 7.3 | 10.8 | 57.5/81.5 | |
| P3K0 | 3.0 (4) | M3 | 7.2 | 10.8 | 6.3 | 9.5 | 11.5 | 16.8 | 9.9 | 14.4 | 75/101.6 | |
| P4K0 | 4.0 (5.5) | M3 | 9.0 | 13.7 | 8.2 | 12.3 | 14.4 | 20.2 | 12.4 | 17.5 | 98.5/133.5 | |
| P5K5 | 5.5 (7.5) | M3 | 12 | 18 | 11 | 16.5 | 16/6 | 19.2 | 27.4 | 16.6 | 23.6 | 131/166.8 |
| P7K5 | 7.5 (10) | M3 | 15.5 | 23.5 | 14 | 21.3 | 24.8 | 36.3 | 21.4 | 30.1 | 175/217.5 | |
| P11K | 11 (15) | M4 | 23 | 34.5 | 21 | 31.5 | 33 | 47.5 | 29 | 41 | 290/342 | |
| P15K | 15 (20) | M4 | 31 | 46.5 | 27 | 40.5 | 42 | 60 | 36 | 52 | 387/454 | |
| P18K | 18.5 (25) | M5 | 37 | 55.5 | 34 | 51 | 34.7 | 49 | 31.5 | 44 | 395/428 | |
| P22K | 22 (30) | M5 | 43 | 64.5 | 40 | 60 | 41.2 | 57.6 | 37.5 | 53 | 467/520 |
Normal overload 150% for 1 minute
(1) Applies to dimensioning of drive cooling. If the switching frequency is higher than the default setting, the power losses may increase. LCP and typical control card power consumptions are included. For power loss data according to EN 50598-2, refer to Danfoss MyDrive® ecoSmartTM website.
8 Special Conditions
8.1 Derating for Ambient Temperature
The ambient temperature measured over 24 hours should be at least 5 °C (9 °F) lower than the maximum ambient temperature. If the drive is operated at high ambient temperature, decrease the continuous output current. The drive has been designed for operation at maximum 50 °C (122 °F) ambient temperature with 1 motor size smaller than nominal. Continuous operation at full load at 50 °C (122 °F) ambient temperature reduces the lifetime of the drive.
8.2 Derating for Low Air Pressure
The cooling capability of air is decreased at low air pressure. Below 1000 m (3280 ft) altitude, no derating is necessary, but above 1000 m (3280 ft), decrease the ambient temperature or the maximum output current. For altitudes above 2000 m (6560 ft), contact Danfoss regarding PELV. Decrease the output by 1% per 100 m (328 ft) altitude above 1000 m (3280 ft), or reduce the maximum ambient temperature by 1 °C (1.8 °F) per 200 m (656 ft).
8.3 Derating for Running at Low Speeds
When a motor is connected to a drive, check that the cooling of the motor is adequate. A problem may occur at low speeds in constant torque applications. Running continuously at low speeds - less than half the nominal motor speed - may require extra air cooling. Alternatively, select a larger motor (1 size up).
9 Technical Documentation
Scan the QR code to access more technical literatures for FC 51. Or, after scanning the QR code, click Global English on the website to select your local region's website, search FC 51 to find the documents with your own languages.
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