The SubDrive Solar controller is a variable speed motor drive designed to run a Franklin Electric three-phase submersible induction motor. The solar system provides water to remote locations by converting high voltage, direct current from a solar array into alternating current to run a standard AC submersible motor. When solar power is not available, the controller can automatically switch to an alternate single-phase AC input such as a generator or inverter from battery, if available. The controller provides fault detection, motor soft start, and speed control. The SubDrive Solar is designed to provide these features with the plug and play ease of installation similar to a single-phase control box.
The SubDrive Solar system can provide water in remote areas where normal power is either unreliable or unavailable. The system pumps water using a high-voltage DC power source such as an array of solar panels.
As the sun is only available during certain hours of the day and only in good weather conditions, the water is generally pumped into a storage tank.
Two level switches can be installed inside the tank to regulate the water level. There is more information below on monitoring the water level.
A flow switch detects if flow is below critical levels while the pump is still running. This serves as an indication that the well has run dry, or that insufficient power is available to continue pumping. The system will shut down to protect the pump and motor until the well, or adequate electric power, has recovered.
The SubDrive Solar controller runs at variable speed to match the changing power available from the PV solar array. Variable speed operation means there is no in-rush or surge of energy during the pump/motor start-up, helping to eliminate wear on the motor and pumping system. A leading cause of pump motor failure is the stress applied to the motor during a full voltage start-up. The SubDrive Solar variable speed operation ramps up the speed smoothly, which eliminates starting stress. This feature enhances long-term motor reliability.
The Franklin Electric SubDrive Solar is designed to be part of a system that consists of:
More installation information can be found here: click here.
The most common method of controlling the flow of water is to use a single run input with a pressure switch. When the tank fills, it closes the double acting float valve, pressure builds up and the pressure switch open circuits which stops the pump. When pressure drops in the line it closes the pressure switch and starts the pump set.
2 Level Control Switch Operation
You can use up to 2 level control switches with the Franklin SubDrive Solar systems. When both switches are installed, the controller starts to pump and waits to shut off until both switches read “OPEN”. Once it shuts off, the controller then waits to run again until both switches read “CLOSED”. An example application (fig 10) is to use separate level switches to indicate high and low water levels. Parameter 1 should be changed to 2 in the menu controls.
1 Level Control Switch Operation
Alternatively, the SubDrive Solar controller may be configured to control the water level by using a single input switch. Parameter 1 in the controller is set to “1” by default for single level control operation. Once it is properly configured for a single active input with a control switch installed, the controller starts to pump and waits to shut off until the active switch reads “OPEN”. Once it shuts off the controller then waits to run again until the switch reads “CLOSED”. An example application (fig 10) would be to use a single-contact level switch that keeps the storage tank as full as possible without overflowing. for single level switch control, use only the “RUN” terminal connection.
0 Level Control Switch Operation
Lastly, the SubDrive Solar controller may be configured to not use a level control switch. Parameter 1 should be changed to “0” in the menu controls. In this configuration, the SubDrive Solar will always try to run the motor and pump water as long as there is enough power from the solar array or alternative AC power source.
All level control switch configurations are superseded by the FLOW SWITCH. If the flow switch detects low flow, it will OPEN and override the run signals sent by the level control switches to protect the motor and drive