SQ innovative motor technology
SQ pumps feature an innovative motor design incorporating permanent-magnet technology. By combining permanent-magnet motors and a Grundfos micro-frequency converter, we are able to deliver unmatched performance and the ability to control and communicate with the pump in ways never before possible.
SQ pump models operate at a constant speed much like today’s conventional pumps. The difference is that SQ delivers the benefits of an electronically controlled permanent-magnet motor that cannot be achieved with a conventional induction motor.
SQ pumps are available for single-phase power; a simple 2-wire design makes installation easy.
High pump efficiency
The hydraulic pump components are polyamide reinforced with 30 % glass fiber. The hydraulic design provides for high pump efficiency resulting in low energy consumption and therefore low energy costs.
High motor efficiency
The motors are based on a permanent magnet rotor (PM motor) featuring high efficiency within a wide load range.
The pump design features "floating" impellers (not fastened to the shaft). Each impeller has its own tungsten carbide/ceramic bearing. The construction and materials ensure high wear resistance to sand for long product life.
Protection against upthrust
Starting up a pump with a very low counter pressure involves the risk of the entire impeller stack being lifted, also called upthrust. Upthrust may cause breakdown of both pump and motor.
SQ motors are fitted with a top bearing protecting both pump and motor against upthrust, thus preventing breakdown during the critical start-up phase.
Excellent starting capabilities
The integrated electronic unit of the motor features soft starting. Soft start reduces the starting current and thus gives the pump a smooth and steady acceleration.
The soft starter minimizes the risk of wear on the pump and prevents overloading of the mains during start-up.
The excellent starting capabilities are a result of the high locked-rotor torque of the permanent magnet motor together with the few pump stages. The high starting reliability also applies in case of low voltage supply.
Overvoltage and undervoltage protection
Overvoltage and undervoltage may occur in case of unstable voltage supply.
The integrated protection of all motors prevents damage to the motor in case the voltage moves outside the permissible voltage range.
The pump will cut out if the voltage falls below 150 V or rises above 315 V. The motor is automatically cut in again when the voltage again falls within the permissible voltage range. Therefore no extra protection relay is needed.
Exposure of the pump to heavy load causes the current consumption to rise. The motor will automatically compensate for this by reducing the speed to 3000 rpm. Further overload will lead to stop.
If the rotor is being prevented from rotating, this will automatically be detected and the power supply will be cut out. Consequently, no extra motor protection is needed.
A permanent magnet motor gives off very little heat to its surroundings. In combination with an efficient internal circulation system leading the heat away from the rotor, stator and bearings, this ensures optimum operating conditions for the motor.
As an extra protection, the electronic unit has a built-in temperature sensor. When the temperature rises too high, the motor is cut out; when the temperature has dropped, the motor is automatically cut in again.
The motors are built for high reliability and feature:
- Tungsten carbide / ceramic bearings
- thrust bearings protecting against downthrust
- product life time equal to conventional AC motors
Important: Any well with a high static water level may allow the pump to operate off the curve and outside its recommended range. We recommend using a "Dole" flow restriction valve to throttle the pump to prevent upthrust damage to the pump and motor. The maximum flow must be restricted to within the pumps recommended operating range.