The Solar Spring pumps can be used at any voltage from 20V (or 2 x 12V or 3 x 12V batteries in series) to 80V, and current from 1 ampere to 4 amperes. They are fitted with a 200W direct current brushed permanent magnet motor which can be used with any photovoltaic panel array from 20 watts up to 360 peak watts nominal installed power. The motor can turn at any speed from 0 rpm to 3000 rpm, and is optimised at 2000 rpm. In contrast with conventional equipment, the Solar Spring motor is insulated against the water and air-cooled and can therefore run dry. Where the pump is operated directly from photovoltaic panels, the use of the Sunprimer electronic booster is necessary. Existing booster technologies MAY NOT WORK with the Solar Spring pumps and/or they may well burn out the pump motors. This is because they were designed to operate with "diaphragm" pumps and not with horizontal axis piston pumps. NEVER attempt to use booster technologies which have not been duly authorised by the manufacturers of the Solar Spring pumps.
In contrast with other small submersible pumps, Solar Spring pumps can be installed at any depth below water level. This enhances their use in areas where seasonal variations in water level in a bore-hole are substantial, and seasonal re-installation would therefore otherwise be required. Solar Spring motors need just 1.5 amps to start up, with irradiance as low as 300W/m2 . They enjoy rugged service. They are also suitable for continuous 24 hours' service (brush wear is proportionate to the number of hours of operation).
The performance and durability features of Solar Spring pumps are due to their patented piston configuration. Solar Spring pumps have two, very large, counter-weighting pistons operating over a very short stroke in balance on a horizontal axis. Other pumps have one or more smaller pistons operating (more or less) vertically over a much longer stroke. The Solar Spring pistons are activated by means of oil bathed cams and vertical bearings. Solar Spring pumps can further be optimised at the moment of supply for a given application by changing cam size and, therefore, piston stroke length, which can be varied from 0.9mm to 1.5mm according to requirements. The four standard versions are those with a 3mm cam for use in shallow installations with high capacities together with the Hyboost inertia amplifier (see notes below), a 2.6mm cam for medium depth installations and capacities, a 2.2mm cam for medium-high lifts, and a 2.0mm cam for very deep installations.
The pump outlet is normally fitted with a non-return valve and an automatic bleeder system. A self-cleaning nipple acting as a bleeder relieves residual pressure in the pump system. This makes start-up under load easier, particularly where the pumps are installed many meters below the water level.
All materials used have been specially chosen for their high resistance to corrosion, abrasion, and wear and tear. Most parts are made from stainless steel or long-lasting plastics, while the pump body is made from brass. All parts operate within their normal materials stress levels up to a depth of 150m. For deeper installations, normal wear and tear will occur.
Notwithstanding the fact that all parts of the Solar Spring pump are to be considered extremely robust, the pump, motor, and Sunprimer electronics unit are to be considered FRAGILE from the point of view of transport and handling. Packets and cartons for transport must be marked FRAGILE and THIS WAY UP with the pumps packed in their natural position vertically. During handling and installation all parts of the pump must be treated with great care. Pumps, motors, and electronics should not be thrown around or dropped or otherwise mis-treated. Failure to take care will void the manufacturer's warranty.
1) The SUNPRIMER booster/kick starter. This is a simple device which is designed to start turning the motor when the ambient insolation value is approaching the minimum required for the pump to continue turning once started. The kick starter stores energy and releases it as a shock charge to the motor. It is designed in such manner that it will not operate when the pump cannot subsequently continue turning with the power then available, that it cannot give a charge greater than the motor can absorb without over-heating, and that it cannot repeat charges at frequencies where their accumulated effect could result in over-heating the motor.
The Sunprimer varies voltage in accordance with the variable available power input from the panels by switching from parallel mode ( two sets of two panels in case of low insolation) to series mode (four panels in series in case of high insolation) to ensure the maximum possible turning speed of the motor, and therefore maximum pump capacity.
The current standard model of the Sunprimer is the MKII, which is designed to cut out when amperage reachs 4.5 amps for one half of one second.
2) The Hyboost inertia amplifier. The Hyboost, specially developed for use with the Solar Spring pumps, performs hydraulically some of the work of an electronic current regulator, especially in high capacity, shallow well applications, where it runs in conjunction with the SUNPRIMER unit. It serves to optimise flow by limiting missmatch phenomena in the hydraulic system. The special rubber ovoids in the Hyboost chamber absorb excess available energy and return it to the water column at the appropriate phase of the pumping cycle. The motor is able to absorb a higher amperage that would otherwise be the case, and pump up to twice as much water. As with the Sunprimer controller it is the global system (PV + pump group) efficiency which is improved, not that of the pump sub-system itself (the Hyboost itself actually absorbs about 3%) . The Hyboost is also suited for use with batteries. Hyboost units progressively lose their effect with the depth of the installation, where motor absorption naturally increases. Benefits fall off sharply after 50m depth and the unit is not recommended for use at depths greater than 60-70m.
The booster does not increase the global efficiency of the pump and motor unit, but it avoids unnecessary wastage of power by exploiting the variable voltage operation feature of direct current motors.
Hyboost units contain a non-return valve to avoid loss of water from the feed pipe where the pump is detached from the feed pipe.
The length of the pipe on the standard version of the Hyboost is 140mm, while the length of the pipe in the Tubo Koala high capacity version (depths not exceeding 30m) is 230mm.
The pumps can be withdrawn from the bore-hole or well in just a few minutes and a complete maintenance of the pump (opening and checking all pump parts, re-assembly, and re-installation) all carried out on site within the space of one half hour. The only exception is the re-winding of motor coils, which, if required, would be carried out elsewhere. The maintenance officer will be equipped with substitute motors to cover this eventuality.