Fronius Tauro 50-3-D50kW three-phase string inverter, 3 MPPT, direct string connection

Overview

The Tauro 50-3-D is a 50kW three-phase string inverter in the direct version: strings plug straight into Stäubli MC4 inputs protected by integrated 20A or 30A string fuses, so no external combiner box is needed. Three MPP trackers rated 36A, 36A and 72A cover a 400–870V MPP window and up to 75kWp of PV. Maximum efficiency is 98.5%, the IP65 double-wall housing operates from -40 to +65°C, and Fronius Arc Guard is available as an option with the 20A fuses.

• Tauro 50: three MPPT; Tauro ECO: one high-voltage MPPT
• Direct (MC4, string fuses) or precombined (combiner box) DC versions
• 98.5% max. efficiency, 50% PV oversizing permitted
• IP65 double-wall housing, -40…+65°C, wall or flat-roof mounting
• Type 1+2 DC/AC surge protection integrated
• CEI 0-21, CEI 0-16, VDE-AR-N 4105/4110 and EN 50549 listed

How it works

Tauro is the Fronius platform for large commercial string systems, built in a 755×1109×346mm double-wall housing with active cooling and IP65 protection for -40 to +65°C. Tauro 50-3 has three MPP trackers and a 400–870V MPP range for arrays with several orientations. Tauro ECO 50, 99 and 100 use a single tracker with a 580–930V window and 650V start-up voltage, intended for large uniform fields with long strings.

Every model comes in two DC versions. The direct (D) version takes strings straight on Stäubli MC4 connectors through integrated 20A or 30A string fuses, so no external combiner box is needed. The precombined (P) version has one DC input per tracker or input group, with cable lugs or V clamps for 25–95mm² aluminium or copper conductors, and the strings are fused in an external combiner box.

Key features

Maximum efficiency is 98.5% on every model, with European efficiency of 98.3% for Tauro 50 and 98.2% for Tauro ECO. Type 1+2 DC and AC surge protection is integrated, with type 2 as an option, together with DC disconnectors, an RCMU and insulation monitoring. Fronius Arc Guard is available as an option on D versions with 20A fuses. Fronius permits 50% oversizing, which gives 75kWp on the 50kW models and 150kWp on ECO 99 and 100.

Installation and compatibility

The inverter mounts vertically on a wall or post, or horizontally on a flat roof at a minimum 3° tilt, where the optional floor racks are recommended. Fronius recommends 80A AC overcurrent protection for a single 50kW unit. A residual current device is not generally required; if one is fitted it must be type B with at least 1,000mA. AC conductors of 35–240mm² (70–240mm² on ECO 99/100) in aluminium or copper are accepted.

With the AC daisy chain version, the AC cable runs from one Tauro to the next up to 200kW in total, with 160A to 355A recommended protection depending on the chained power. TT (with N–PE voltage below 30V), TN-S, TN-C and TN-C-S earthing systems are permitted, IT is not. Fronius excludes installation in stables, feed stores and areas with ammonia or corrosive gases.

Monitoring and settings

An integrated data logger and web server connect each inverter directly to Fronius Solar.web over WLAN or Ethernet, in a star topology on multi-inverter sites. Modbus TCP SunSpec, the Solar API (JSON) and two RS485 ports for Modbus RTU SunSpec serve SCADA systems and the Fronius Smart Meter, which enables feed-in limitation. Six digital inputs and six I/Os handle ripple control receivers and load control, wired shutdown provides an emergency stop chain, and commissioning uses the Fronius Solar.start app.

Questions and answers