Valves, Actuators & Pump Control

Drives for solar-powered pump systems

February 2021 Valves, Actuators & Pump Control

BMG’s electromechanical specialists, with extensive experience in gearing, have extended their solutions service to include solar inverters and drives, which are designed to enhance efficiency of photovoltaic (PV) systems.

“PV modules, which use sunlight to generate electricity, are gaining popularity globally as a form of renewable energy that is clean, emission-free, sustainable, safe and cost efficient,” explains Mick Baugh, electronics manager, BMG’s electromechanical division. “Through the use of environmentally-friendly PV technology to generate electrical power, companies in South Africa are finding effective solutions to combat the country’s grave electricity crisis. The benefits of using eco-friendly solar-powered pumps for irrigation, animal farming and community water supply include an uninterrupted water supply during the day and independence from the unreliable grid. In addition, advanced PV systems require minimal maintenance, which is an important advantage in remote areas where servicing is difficult.

“Solar pump systems, which are particularly popular in remote areas where electricity is unavailable, require a solar inverter to convert the DC generated by solar panels into AC for use in industrial, commercial and residential applications. A key differentiator in the selection of the correct inverter is its ability to run the motor pump at the optimal working voltage and power ratings, to ensure solar panels deliver the highest possible power in various irradiation and ambient temperature conditions.

“For optimum performance of the PV pump system, we believe it is critical for users to fully understand the control strategy of the system and to consider factors like where to install the drive, condensation issues, the temperature range and the backup supply.”

Control strategy

Simpler solar-powered drives for pumping applications operate as under-voltage regulators, lowering the pump speed (thus reducing the absorbed power) when the DC voltage reaches a minimum voltage set-point. This simple control mode negatively impacts performance of the PV modules, since they operate at a non-optimal voltage.

In advanced controllers, the drive works to obtain the maximum power from solar panels by keeping the DC voltage at the MPP (maximum power point). Drives that operate at a constant DC voltage must be selected depending on the electrical characteristics of the installed PV system and should optimise the hydraulic efficiency of the pump.

BMG specialists recommend the use of Vacon solar-powered drives that feature MPPT (maximum power point tracking) control to ensure an optimal operating voltage for PV modules in pump applications. These highly efficient controllers provide extended running hours, with an earlier start and later stop. Consequently, more water is pumped per Watt-peak (Wp) of installed PV modules, leading to reduced investment costs and a quicker payback period. MPPT controllers detect instantaneous irradiance or temperature variations and omit local maximums, which are generated in partial shading conditions or from degraded modules in the PV array.

Cabinet or outdoor installations

Conventional solar pump inverters are usually IP20 or IP21 devices that are installed inside a cabinet along with components, including fuses, a power switch, lightning protection and door-mounted LEDs/bulbs. BMG specialists do not recommend this system because cabinets need to be ventilated to avoid overheating of the enclosed elements. Overheating produces derating and reduces the lifetime of the drive. Also, airflow though the cabinet needs to be filtered to avoid dust collection, and filters must be periodically cleaned and replaced, which increases risks and maintenance costs.

BMG’s Vacon IP66 drive solutions for outdoor installations consist of small enclosures, which are separated from the drive, to house the mains switch and surge protection device. The Vacon IP66 drive can be installed outdoors without any reliability risk and does not require maintenance, as there are no filters to clean or replace. Drives can be mounted in the same structure as the PV modules, taking advantage of their shading to avoid overheating, and thus derating, due to direct sun on the drive.

This ground-level system is fitted with LEDs that allow external visibility of the operating conditions of the drive, including power-on, run, ready and fault. An IP66 display panel provides detailed information on the drive, like running speed and MWh readings.

The enclosure, which is separated from the drive, gives the installer flexibility when designing a cabinet that is suitable to run a pump in different layouts.

For more information contact Mick Baugh, BMG, +27 11 620 1538,,


Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

BMG’s heavy-duty mechanical face seals
Bearing Man Group t/a BMG News
BMG’s extensive range of seals and gaskets includes Trelleborg mechanical face (torric) seals, which have been specially engineered for rotating applications in arduous conditions.

Conveyor chain for special applications
Bearing Man Group t/a BMG Motion Control & Drives
BMG’s comprehensive range of power transmission components incorporates ZMC industrial conveyor chains that offer dependable service in diverse applications, especially in food production.

BMG’S Nord IE5+ motor generation
Bearing Man Group t/a BMG Motion Control & Drives
BMG and German precision engineers, Getriebebau Nord, entered a partnership agreement in 1996 to assemble, distribute and support Nord Drive Systems throughout southern Africa.

BMG gearboxes for railway maintenance
Bearing Man Group t/a BMG Maintenance, Test & Measurement, Calibration
BMG supplies the local railways sector with custom-designed planetary gearboxes for use in railway maintenance programmes.

Smart pumping – a new era in water management and supply
Schneider Electric South Africa Valves, Actuators & Pump Control
Smart pumping can address the high cost and energy usage challenges faced by private and municipality-managed facilities.

Schubert & Salzer and Macsteel
Macsteel Service Centres Valves, Actuators & Pump Control
The demand on valves, particularly in tyre production plants, is extreme with tyre curing presses working constantly at high temperatures and pressures.

Chinese LNG tanker fitted with ARCA anti-surge valves
Valve & Automation Valves, Actuators & Pump Control
ARCA anti-surge valves avoid surging by accurately adjusting the gas circulation or blow-off flow, effectively protecting the safety of the compressor unit.

V-belts designed for food applications
Bearing Man Group t/a BMG Motion Control & Drives
BMG supplies a wide range of power transmission components, designed to enhance efficiency and safety in the food and beverage sector.

Electrified subsea actuator for offshore production
Valves, Actuators & Pump Control
Bosch Rexroth has engineered the SVA R2 Subsea Valve Actuator as a disruptive innovation for electrically actuating valves in the subsea process industry. It can replace conventional hydraulic cylinders ...

BMG boosts solutions through Heko products
Bearing Man Group t/a BMG News
Through the supply and support of Heko products, BMG has boosted its solutions service to customers wanting to optimise the efficiency of their bulk material conveyor systems.