The Grundfos Renewable Solar Inverter (RSI) is an off- grid solar inverter converting the DC power output from the solar panel to AC power supply for pump operation.
RSI can be used in both new and existing systems as long as the motor specifications are compatible and the motor is suitable for use with a variable frequency drive.
The list below contains the Grundfos pump types for use in applications with RSI:
• Grundfos CR
• Grundfos SP
• Grundfos NB, NK
• Grundfos MTR
• Grundfos CM
• Grundfos TP
RSI is designed for continuous as well as intermittent operation. The system is suitable for various water supply systems, including irrigation.
RSI can be used in existing systems with submersible pumps or dry-installed pumps, thus providing a very wide range of applications allowing you to leverage renewable energy sources with the ability to back up the system with grid or generator power.
Enclosure classes up to IP66
RSI is available in three enclosure classes: IP21, IP54 and IP66.
• IP21: RSI must be installed in a cabinet with sufficient ingress protection.
• IP54: RSI can be installed without a cabinet, but must not be installed outdoors without additional protection against water and sun.
• IP66: RSI can be installed without a cabinet. It can be installed outdoors, but should be shaded from direct sunlight.
Setup wizard with Grundfos product library
RSI has a built-in Grundfos product library which allows a plug-and-pump experience. The motor library contains all related parameters, which simplifies the setup process to just a few clicks and a setup time of a few minutes.
Detachable operating panel
The operating panel is mounted on RSI by using a magnet and a communication plug. The inverter can operate without the operating panel and operates with the last saved setup data.
RSI is AC and DC compatible. RSI can be connected to the grid or a generator as back-up power during solar panel disruptions.
The AC compatibility also allows the end user to connect the inverter to three-phase power in their workshop for off- site setup, which enables a fast and simple on-site installation.
Maximum power point tracking (MPPT)
The inverter has built-in electronics with four MPPT algorithms. The inverter continuously optimises the power output according to available solar irradiation as well as various environmental conditions.
No-load situation of the inverter may occur if, for example, the cable to the motor is broken. The inverter disconnects the power connection to the motor if no-load occurs. The inverter stays in fault mode with the error code displayed until reset.
For the no-load protection to function properly, check the RSI installation and operating instructions carefully and follow them during operation.
Pump requirements for an RSI system:
• The rated frequency can be either 50 or 60 Hz.
• The pump must be able to operate with a voltage supply of 3 x 380 VAC or 3 x 220 VAC.
As standard, Grundfos three-phase pumps can only be operated via an AC voltage supply. Therefore, the solar panels must not be connected directly to the pump but must be connected via an RSI.
Electrical and enclosure data
•Minimum ambient temperature : -10°C
•Maximum ambient temperature : 60°C
•Maximum relative humidity : 100%
•Minimum MPP voltage : 450VDC
•Recommended MPP voltage : 530-615VDC
•Maximum input voltage : 800VDC
•Input voltage : 380-480VAC
•Rated output voltage : 380-440VAC
•Minimum frequency : 5Hz
•Maximum frequency : 160Hz
•Phases : 3
•Enclosure class : IP54, IP66
Output filters are used for reducing the voltage stress on the motor windings and the motor insulation system as well as for decreasing acoustic noise from the motor driven by a frequency converter.
One type of output filter is available as an accessory for the RSI:
• sine-wave filters.
RSI input terminals
Make sure that AC and DC power source are never supplied to the RSI simultaneously, unless it is installed with PowerAdapt. An interlocked change over switch is recommended.
The terminals of the Standard I/Os and the Relays are described below. The terminals shown on shadowed background are assigned for signals with optional functions selectable with DIP switches. See more information in RSI Installation Manual.