Grundfos Submersible Pump SQ 7 SQ 7-N, SQE 7, SQE 7-N
1. Product Introduction
SQ pumps are submersible pumps available in the
following versions:
• SQ
• SQ-N
• SQE
• SQE-N
• SQE-NE.
Applications
SQ and SQE pumps are suitable for both continuous and intermittent operation for a variety of applications:
• domestic water supply
• small waterworks
• irrigation
• tank applications
• pressure boosting.
SQE-NE pumps are suitable for environmental applications, such as remedial pumping or sampling at:
• refuse dumps
• chemical sites
• industrial sites
• garages and petrol stations.
Note: For other applications, please contact Grundfos
Features and Benefits
SQ pumps offer the following features:
• dry-running protection
• high pump and motor efficiency
• wear resistance
• protection against upthrust
• soft starter
• overvoltage and undervoltage protection
• overload protection
• overtemperature protection.
Additionally, SQE pumps offer the following benefits:
• variable speed
• electronic control and communication.
The motors are based on the most recent technology within permanent magnets. This technology is the main reason for the high efficiency of the motors. The motors have a built-in electronic unit containing a frequency converter featuring soft start.
SQ pumps are fitted with a single-phase Grundfos MS 3 or MS 3-NE motor, and by means of the built-in frequency converter, the motor is driven at a constant speed.
SQE pumps are also fitted with a single-phase Grundfos MSE 3 or MSE 3-NE motor. Both motor types can communicate with the Grundfos CU 300 and CU 301 control units, which can be operated with Grundfos GO Remote.
SQE pumps feature variable speed which is offered through frequency control. This means that the pump can be set to operate in any duty point in the range
between the pump minimum and maximum performance curves.
CU 301 is specially developed for applications where a constant pressure is required.
CU 300 and CU 301 provide full control of SQE pumps.
In case of pump fault, the front of the CU 300 or CU 301 shows an alarm. Grundfos GO Remote enables monitoring of the installation and changing of the factory settings.
SQE pumps can operate without a CU 300 or CU 301. However, in such case, the pump does not offer all the features available when connected to a CU 300 or a CU 301.
Pumped liquids
The SQ and SQE pumps are suitable for pumping thin, clean, non-aggressive, non-explosive liquids, not containing solid or long-fibred particles larger than sand grains. The pH value of the pumped liquid should be between 5 and 9.
The SQE-NE pumps are applicable in contaminated or hydrogen-carbonate-containing groundwater. The pH value should be between 2 and 13.
Sand content
The maximum sand content allowed is 50 g/m3.
A higher sand content will reduce pump life due to wear.
Temperature
Due to differences in regulations, temperature limits have been determined according to the following regions:
• West European
• Central European
• Asian-Pacific
• North American.
For the West European, Central European and Asian-Pacific region, the following table applies:
Temperature limit on the motor nameplate: 35 °C.
Note: UL accepts only one temperature limit to be stamped on the motor nameplate. Identical motors are used in the following regions:
• West European
• Central European
• Asian-Pacific
• North America.
For the North American region, the following table applies:
Note: According to UL regulations, the temperature of the pumped liquid must not exceed 86 °F (30 °C) for products in the North American region.
Viscosity
The pumping of liquids with a viscosity higher than that of water will cause the following:
• head loss
• higher power consumption.
If in doubt, contact Grundfos.
2. Features and benefits
Dry-running protection
The pumps are protected against dry running. A value of pcut-out ensures cut-out of the pump in case of water shortage in the borehole, thus preventing a burnout of the motor.
The dry-running protection is active after 30 seconds of operation. The dry-running alarm is activated when the load has been below the minimum power limit for an accumulated time of 5 seconds.
Pcut-out is factory-set both for the SQ and SQE pumps.
On SQE, the dry-run limit can be adjusted with Grundfos GO
High pump efficiency
The hydraulic pump components are polyamide-reinforced with 30 % glass fibre. The hydraulic design ensures high pump efficiency, yielding low energy consumption and thus low energy costs.
High motor efficiency
The motors are designed according to the permanent-magnet principle (PM motor), featuring high efficiency within a wide performance range
Wear resistance
The pump impellers are not fastened to the shaft (''floating''). Each impeller has its own tungsten carbide/ceramic bearing. The design and the materials chosen ensure high wear resistance to sand, thus 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. This phenomenon is called upthrust. Upthrust may cause breakdown of both pump and motor.
The motors are fitted with an upthrust 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 includes soft starting. Soft starting reduces the starting current, thus gives the pump a smooth and steady acceleration.
The soft starter minimises the risk of wear of 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, and the few pump stages. 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 is cut out if the voltage falls below 150 V or rises above 315 V. The motor automatically restarts when the voltage returns within the permissible range.
Consequently, no extra protection relay is required.
Overload protection
If the pump is exposed to heavy load, the current consumption rises. The motor automatically compensates for this by reducing the speed. If the speed falls below 3000 min-1, the motor is cut out.
If the rotor is prevented from rotating, it is automatically detected and the power supply is cut out.
Consequently, no extra motor protection is required.
Overtemperature protection
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, optimum operating conditions are ensured for the motor.
As an extra protection, the electronic unit has a built-in temperature sensor. When the temperature exceeds a critical limit, the motor is cut out. When the temperature returns below the limit, the motor is automatically cut in again.
Reliability
The motors have been designed with high reliability and have the following features:
• tungsten carbide or ceramic bearings
• thrust bearings protecting against downthrust
• product life equal to conventional AC motors.
Variable speed
The MSE 3 motor enables variable speed control within the range of 3,000 to 10,700 min-1. The pump can be set to operate in any duty point within the 3,000 to 10,700 min-1 performance range of the pump.
Consequently, the pump performance can be adapted to any specific requirement.
The variable-speed control facility requires the use of a CU 300 or CU 301 control unit and Grundfos GO Remote
Installation
SQ and SQE may be installed vertically, horizontally or in any position in between.
Note: The pump must not fall below the horizontal level in relation to the motor.
The following features ensure simple installation of the pump:
• built-in non-return valve with spring
• low weight facilitating handling
• installation in 3-inch or larger boreholes
• on/off switch without extra motor starter or starter box necessary
• SQE available with cable with a motor plug (up to 100 m).
For horizontal installation, we recommend that you install the pump in a flow sleeve, for the following reasons:
• to ensure sufficient flow velocity past the motor, thus provide sufficient cooling
• to prevent motor and electronic unit from being buried in sand or mud.
Service
The modular pump and motor design facilitates installation and service. The cable and plug are fitted to the pump with screws, which enables replacement.
Pump Sizing
SQ 7-15 (-N)
SQE 7-15 (-N)
SQ 7-30 (-N)
SQE 7-30 (-N)
SQ 7-40 (-N)
SQE 7-40 (-N)
