Grundfos MS, MMS Submersible Motors

General Description

Grundfos MS and MMS submersible motors are designed according to market standards. They are suitable for various applications including water supply for irrigation, groundwater regulation, pressure boosting, and industrial water transfer. These motors are designed to fit pump ends manufactured according to NEMA standards.

Applications

Grundfos MS and MMS submersible motors are ideally suited as water supply pumps for irrigation, groundwater regulation, pressure boosting, industrial water transfer, and similar applications.

Pumped Liquids

The motors are designed for pumping clean, thin, non-flammable, non-combustible, or non-explosive liquids that do not contain solid particles or fibres. The maximum sand content must not exceed 50 g/m³. Specific motor versions (N, R, RE) are designed for liquids with higher aggressiveness than drinking water.

Materials in contact with the liquid include cast iron (DIN W.-Nr. 0.6025), stainless steel (DIN W.-Nr. 1.4401, 1.4539), NBR rubber, and FKM rubber, depending on the motor model.

Sound Pressure Level

The sound pressure level for Grundfos MS and MMS motors is lower than 70 dB(A), measured in accordance with the EC Machinery Directive 98/37/EC.

Delivery and Storage

Delivery

Submersible motors are supplied from the factory in proper packing and should remain in this packing until installation.

Unpacking

Handle the motor cable with care during unpacking to avoid damage from sharp tools. The separate nameplate must be fixed close to the installation site. Avoid unnecessary impact and shocks.

Storage and Handling

Storage temperature range: -20 °C to +70 °C. If MMS motors are stored, the shaft must be turned by hand at least once a month. Motors stored for over a year require dismantling and checking of rotating parts before use. Do not expose motors to direct sunlight.

Warning: Do not stack boxes of different lengths.

Frost Protection

If stored, motors must be kept in a frost-free location, or the motor liquid must be frost-proof. Motors are factory-filled with demineralised water; use a special Grundfos liquid for refilling if frost protection is required.

Preparation

Warning: Before starting work, switch off the power supply and ensure it cannot be accidentally switched on.

Warning: Use a strap or lifting eye and a crane for lifting to avoid personal injury.

Checking of Liquid in Motor

Submersible motors are factory-filled with a special FDA-approved, non-toxic liquid, frost-proof down to -20 °C. The liquid level must be checked and refilled if necessary, typically with tap water. If frost protection is required, use a special Grundfos liquid.

Refilling Procedure (MS 402 and MS 4000)

Position the motor with the filling hole at the highest point. Remove the filling screw and inject liquid until it runs back out. Replace and tighten the screw (Torque: MS 402: 2.0 Nm, MS 4000: 3.0 Nm).

Refilling Procedure (MS 6000)

If delivered from stock or during service, check the liquid level. Position the motor with the filling hole at the top. Remove the screw, inject liquid until it runs back out, then replace and tighten the screw (Torque: 3.0 Nm).

Refilling Procedure (MMS6, MMS 8000, MMS 10000, MMS 12000)

Place the motor at a 45° angle with the top upwards. Unscrew plug (A), place a funnel, and pour tap water until it runs out at plug (A). Do not use oily motor liquid. Remove funnel and refit plug (A). Before fitting after long storage, lubricate the shaft seal.

Positional Requirements

Motors can be installed vertically or horizontally. For horizontal installation, refer to the table for suitable motor types and power ratings.

Caution: During operation, the motor must always be completely submerged in the liquid. Consult pump manufacturer's NPSH data.

Warning: If used in hot liquids (40-60 °C), ensure no one can come into contact with the motor, e.g., by installing a guard.

Liquid Temperatures/Cooling

The maximum liquid temperature and minimum flow velocity past the motor are detailed in a table. Grundfos recommends installing the motor above the well screen for proper cooling. A flow sleeve may be required if the stated flow velocity cannot be achieved or if there is a risk of sediment build-up.

Electrical Connection

Warning: Before starting work, switch off the power supply and ensure it cannot be accidentally switched on.

General

Electrical connection must be performed by an authorized electrician according to local regulations. Supply voltage, rated current, and cos φ are on the nameplate. Voltage quality requirements are -10%/+6% of nominal voltage. Ensure voltage symmetry between phases.

Warning: The motor must be earthed. Connect to an external mains switch with a minimum contact gap of 3 mm.

For MS motors with built-in temperature transmitters (Tempcon) not used with an MP 204 unit, a 0.47 µF capacitor (IEC 384-14) is required for EMC directive compliance. This capacitor connects to the two phases used by the temperature transmitter.

Frequency Converter Operation

Three-phase MS and certain MMS motors (PE/PA) can be connected to a frequency converter. If an MS motor with a temperature transmitter is connected, the transmitter fuse will melt, rendering it inactive. A Pt100 sensor is available as an accessory. Avoid running the motor at frequencies higher than rated, and ensure sufficient cooling liquid flow. Use a sinus filter between the converter and motor to mitigate acoustic noise and voltage peaks. Voltage peak limits and dU/dt values are provided in a table.

Motor Protection

Single-phase Motors

Single-phase MS 402 motors (< 1.1 kW) have built-in protection. The 1.1 kW MS 402 requires external current protection. Warning: Terminals remain live when thermally switched off; automatic restart occurs upon cooling. Single-phase MS 4000 motors require external protection.

Three-phase Motors

Protection requirements vary based on whether the motor has a built-in temperature transmitter (Tempcon) or a Pt100 sensor. Options include motor-protective circuit breakers with thermal relays or MP 204 motor protection units with contactors. Specific settings for motor-protective circuit breakers are recommended, including overload settings and trip times. For star-delta starting, specific settings apply.

Caution: Failure to meet start/stop ramp time requirements (3 sec. max) can invalidate the warranty.

Lightning Protection

An overvoltage protection device can protect against surges from lightning strikes, but not direct strikes. Connect it close to the motor and follow local regulations. MS 402 motors have high insulation and require no additional lightning protection. Special cable termination kits with built-in protection are available for 4" motors.

Cable Sizing

Submersible motor cables must be dimensioned for submersion. Cable cross-section must handle rated current and limit voltage drop. Grundfos provides a cable sizing tool. Alternatively, use diagrams and formulas provided to determine the required cross-section based on cable length, voltage, current, power factor, and permissible voltage drop. Formulas for single-phase and three-phase motors are given.

Motor Installation

Warning: Before starting work, switch off the power supply and ensure it cannot be accidentally switched on.

Fitting the Pump to the Motor

Use pipe clamps for handling. Place the motor vertically at the borehole. Lift the pump part using pipe clamps fitted to the riser pipe. Place the pump on the motor and cross-tighten nuts to specified torques. Ensure proper coupling engagement.

Fitting of Submersible Drop Cable and Motor Cable

Ensure the cable socket is clean and dry. Lubricate rubber parts of the plug with non-conducting silicone paste. Tighten cable screws to specified torques. Use original Grundfos cable termination kits. Shorten motor cable if necessary to ensure it is covered by pump medium.

Maximum Installation Pressure

Maximum installation pressures (mWC) are specified for MS 402, MS 4000, MS 6000, and MMS motors.

Lowering the Pump

Check the borehole for unobstructed passage before lowering. Lower the pump assembly carefully, avoiding damage to cables. Do not lower or lift by the motor cable.

Frequency of Starts and Stops

Recommended and maximum frequencies of starts and stops per year, hour, and day are provided for various motor types (MS 402, MS 4000, MS 6000, MMS6, MMS 8000, MMS 10000, MMS 12000) and winding types (PVC, PE/PA).

Maintenance and Service

Motors are maintenance-free and easy to service. Service kits and tools are available from Grundfos. Motors can also be serviced at Grundfos service centres.

Warning: If a motor has been used in hazardous or toxic liquid, it is classified as contaminated. Clean properly before service. Contact Grundfos for details on contamination before dispatching; otherwise, service may be refused. Return costs are the customer's responsibility.

Fault Finding

A table lists common faults (e.g., motor does not run) with their causes (e.g., blown fuses, tripped breaker, no power) and remedies (e.g., replace fuses, reset breaker, contact power company).

Checking of Motor and Cable

Supply Voltage

Measure voltage between phases (or phase-neutral for single-phase) using a voltmeter at the motor-protective circuit breaker terminals. Voltage should be within specified limits when loaded. Large variations indicate poor power supply.

Current Consumption

Measure current in each phase while the pump operates under load. For three-phase motors, the difference between phases should not exceed 5%. Exceeding rated current or phase imbalance may indicate burnt contacts, poor connections, incorrect voltage, short-circuited windings, or an overloaded pump.

Winding Resistance

Disconnect the drop cable and measure winding resistance between leads. For three-phase motors, deviation between highest and lowest values should not exceed 10%. On single-phase, 3-wire motors, the operating winding has the lowest resistance.

Insulation Resistance

Measure insulation resistance from each phase to earth (frame) using an insulation tester (500 VDC, 2 min.). Minimum values are specified for motors with and without drop cables, for new and used motors. Low resistance requires repair.

Disposal

Dispose of the product or parts in an environmentally sound way via public/private waste collection services or by contacting the nearest Grundfos company or service workshop.

Appendix

The appendix contains nomograms (graphical calculation tools) for determining cable cross-section (q) based on current (I), voltage (U), cable length (L), and permissible voltage drop (ΔU). These charts cover various voltage configurations (e.g., 1x230V, 3x400V, 1x220V, 3x380V, 3x220V, 3x440V, 1x240V, 3x415V) and provide an example of how to use the charts by drawing a line between current and length values to find the corresponding cross-section.

Declarations of Conformity

The document includes EU Declarations of Conformity for the MS and MMS products, issued by Grundfos. These declarations confirm conformity with relevant EU Council Directives. Declarations are provided in multiple languages, including English, Bulgarian, Czech, Danish, German, Greek, Spanish, Estonian, Finnish, French, Croatian, Hungarian, Italian, Lithuanian, Latvian, Dutch, Polish, Portuguese, Romanian, Russian, Slovak, Slovenian, Swedish, Turkish, and Ukrainian.

Grundfos Companies Worldwide

A list of Grundfos companies and their contact details is provided for various countries, including Argentina, Australia, Austria, Belgium, Belarus, Bosnia and Herzegovina, Brazil, Bulgaria, Canada, China, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hong Kong, Hungary, India, Indonesia, Ireland, Italy, Japan, Korea, Latvia, Lithuania, Malaysia, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russia, Serbia, Singapore, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Taiwan, Thailand, Turkey, Ukraine, United Arab Emirates, United Kingdom, U.S.A., and Uzbekistan.