Delta M50A-260 - User Manual

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

This document describes the Delta M50A_260 Solar Inverter, a grid-connected solar inverter designed for stationary solar systems. It converts DC power generated by solar modules into AC power for feeding into the local power grid. The inverter is available in product versions L and M, and is compatible with DSS software version 6.0 or higher.

Function Description

The M50A_260 inverter is a crucial component in a solar PV system, facilitating the conversion of direct current (DC) from solar panels into alternating current (AC) suitable for grid injection. It features six Maximum Power Point Trackers (MPPTs), each capable of handling two DC connections, allowing up to 12 module strings to be connected. This design optimizes power harvesting from various solar module configurations. The inverter includes integrated string monitoring, which uses current sensors to monitor the performance of individual module strings. For instance, for a DC input with two module strings, one sensor measures the current of the first string, and another measures the sum current of both, allowing the current of the second string to be calculated by difference.

The device is equipped with various communication interfaces for monitoring and control, including two RS485 ports, dry contacts, digital inputs, and an external power-off (EPO) terminal. It also supports Sub-1G antenna (included) and an optional Wi-Fi module for flexible data logging and remote management. The inverter can be commissioned using the Delta Service Software (DSS) on a Windows PC or the MyDeltaSolar app on mobile devices, either through a direct Wi-Fi connection or via a DC1 data collector. This allows for parameter setting, firmware updates, and comprehensive system monitoring.

Safety features are integral to the M50A_260. It incorporates replaceable Type 2 AC and DC surge protection devices (SPDs) to safeguard against excessive voltages. Combined Type 1+2 SPDs are available as accessories. The inverter also includes an integrated universal current-sensitive residual current monitoring unit (RCMU) certified to VDE 0126-1:2013-08 §6.6.2, ensuring that it does not supply DC residual current to the grid. External grid and system protection is not required as the inverter meets the VDE-AR-N 4105 requirement for an internal coupling switch that disconnects the inverter from the grid in less than 100 ms.

The cooling system comprises a fan module with three fans for circulating ambient air and two internal fans to prevent heat buildup, all of which are replaceable. Air is drawn in from the left side and expelled through outlets on the right.

Important Technical Specifications

Input (DC):

Maximum input power: 11.7 kW per MPP Tracker, 58.0 kW total.
Rated power: 50 kW.
Input voltage range for operation: 200 to 1000 VDC.
Maximum input voltage: 1100 VDC.
Nominal voltage: 600 VDC.
Number of MPP trackers: 6.
MPPT input voltage range total: 200 to 1000 VDC.
Maximum input current: 26 A per MPP Tracker, 132 A total.
DC short-circuit current (ISC): 50 A per MPP tracker.
DC connector panel: Amphenol H4 connector, 12 pairs.
DC cable specifications: 4/6 mm².
Surge protection devices: Type 2 (EN 50539-11) replaceable; Type 1+2 combined upgradeable.
Galvanic isolation: No.

Output (AC):

Maximum apparent power: 55 kVA.
Maximum active power: 55 kW.
Rated apparent power: 50 kVA.
Rated voltage: 230/400 V -20%/+30%, 3 phases + PE (Δ), 3 phases + N + PE (Y).
Rated current: 72.5 A.
Maximum current: 83 A.
Frequency range: 50 / 60 Hz ± 5 Hz.
Adjustment range power factor: 0.8 cap. to 0.8 ind.
Total harmonic distortion: <3% at rated apparent power.
AC connection: Terminal with hexagon socket screw (L1, L2, L3, N), M10 threaded bolt with nut (PE).
Copper cable specifications: 16 to 60 mm² (single wire, multi-wire, fine-wire with wire end sleeve).
Aluminum cable specifications: 25 to 60 mm² (round single-wire, round multi-wire, sector-shaped).
Surge protection devices: Type 2 (EN 61463-11) replaceable; Type 1+2 combined upgradeable.

General Specifications:

Dimensions (W x H x D): 699 × 629 × 264 mm.
Weight: 64 kg.
Protection degree: IP65 (Electronics).
Safety class: II.
Overall operating temperature range: -25 to +60 °C.
Operating temperature range with nominal power: -25 to +50 °C.
Relative humidity: 0 to 100%, non-condensing.
Max. operating height: 4000 m above sea level.
Noise level: <65 dB(A).

Usage Features

The M50A_260 offers flexible installation options, supporting both suspended wall mounting and free-standing ground mounting (with optional feet). For outdoor installations, it is recommended to protect the inverter from direct sun, UV radiation, rain, and snow to prevent power reduction due to overheating. Proper air circulation and adherence to minimum clearances (e.g., >300 mm sides, >200 mm top/bottom, >60 mm front) are essential for optimal performance. When installing multiple inverters, a separation plate is recommended for clearances between 30-60 cm to prevent heat buildup.

The inverter's communication capabilities allow for comprehensive plant monitoring and control. It supports connection to a data logger via RS485, enabling the monitoring of PV system performance and modification of inverter settings. Multiple inverters can be daisy-chained via RS485, requiring unique inverter IDs and consistent baud rates. External alarm units can be connected via dry contacts, and a ripple control receiver can be integrated to manage active power limitation based on grid operator signals. An external power-off (EPO) function is also available for emergency disconnection.

The user interface includes LEDs that provide visual status indications for grid connection, alarms, communication, and operational modes (e.g., standby, firmware update).

Maintenance Features

Regular maintenance is crucial for the longevity and performance of the M50A_260. The manual provides detailed instructions for cleaning and replacing various components.

Cleaning:

Air outlets: The air filters can be unscrewed, removed, and cleaned with compressed air or a firm brush while the inverter is running.
Internal fans: Internal fans can be cleaned with compressed air or a firm brush after disconnecting the inverter from power sources.
Fan module: The entire fan module, which contains three fans, can be removed and cleaned.

Replacement:

Internal fans: Both internal fans (fan 1 and fan 2) are replaceable. The procedure involves disconnecting power, removing covers, unscrewing the fan from its housing, and replacing it with a new one.
Fan module: The entire fan module is replaceable.
DC surge protection devices (SPDs): The Type 2 DC SPDs are replaceable as a block. If Type 1+2 combined DC SPDs are installed, they can also be replaced following similar procedures.
AC surge protection devices (SPDs): The Type 2 AC SPDs are replaceable as a block. If Type 1+2 combined AC SPDs are installed, they can also be replaced.
Sub-1G antenna: The Sub-1G antenna can be installed or replaced during operation.
Wi-Fi module: The optional Wi-Fi module is replaceable.

All replacement procedures require the inverter to be disconnected from all power sources and a waiting period of 60 seconds for internal capacitors to discharge. Special tools, such as a magnetic screwdriver for small screws and an insulated torque wrench for AC terminal blocks, are recommended. The manual emphasizes the importance of reusing screws, spring washers, and washers from old SPDs for new ones. For aluminum conductors, specific handling instructions are provided to ensure safe and reliable contact, including mechanical cleaning of stripped ends and application of neutral Vaseline.