Grundfos MG Motors

1. Symbols Used in this Document

[Warning] If these safety instructions are not observed, it may result in personal injury.

[Warning] If these instructions are not observed, it may lead to electric shock with consequent risk of serious personal injury or death.

[Warning] The surface of the product may be so hot that it may cause burns or personal injury.

[Caution] If these safety instructions are not observed, it may result in malfunction or damage to the equipment.

[Note] Notes or instructions that make the job easier and ensure safe operation.

1.1 Safety

Observe the safety instructions to ensure correct installation, operation, and maintenance of the motor. The instructions must be known by any person installing, using, or maintaining the motor. Failure to observe the instructions may invalidate the warranty.

Safety equipment required to prevent accidents must be made available according to local safety instructions.

[Warning] Prior to installation, read these installation and operating instructions. Installation and operation must comply with local regulations and accepted codes of good practice.

2. Introduction

These installation and operating instructions apply to Grundfos MG motors.

For model designation, see section 4.2 Type key.

2.1 Application

MG motors can be used within the framework of IEC 60034.

3. Delivery and Handling

3.1 Delivery

Immediately after receipt, check the motor for external damage. If damage is found, contact the shipping agent immediately. Verify that all nameplate data are according to specifications, especially voltage, and ensure the winding is correctly connected according to the wiring diagram in the terminal box cover and nameplate data.

3.1.1 Unpacking

[Caution] Do not use sharp tools when unpacking the motor. Avoid unnecessary impact and shocks to the motor. Remove any transport protectors. Turn the shaft by hand to check that it rotates freely.

3.2 Handling

3.2.1 Lifting the motor

Lift the motor using the eye bolts. Take care not to damage additional equipment and cables. The table below shows the number of eye bolts and the maximum permissible weight.

Frame sizes 71 and 80 do not have eye bolts.

3.2.2 Storage

Until installation, Grundfos motors should be stored in their original packaging. Store motors in an enclosed, dry, and well-ventilated room. For protection, treat unprotected machine surfaces (shaft ends and flanges) with a corrosion inhibitor.

[Caution] If MG motors are stored, the shaft must be turned by hand at least once a month to prevent it from getting stuck and to distribute the bearing grease. If the motor has been stored for more than two years before installation, the rotating parts must be dismantled and checked. Relubricate motors with lubricating nipples. Replace greased-for-life bearings.

Storage temperature: -20 °C to +60 °C.

4. Identification

4.1 Nameplate

The motor has two nameplates: one with electrical data (50 and 60 Hz) and one with mechanical data (irrespective of frequency). The nameplates are positioned on the side of the motor.

4.2 Type Key

[Note] Both 50 and 60 Hz data are indicated on the nameplates for three-phase motors. Only 50 or 60 Hz data are indicated on the nameplates for single-phase motors. Only 60 Hz data are indicated on previous versions of ML motors.

The type designation is stated on the nameplate.

Example Type Designation: MG 132 S B 2 -38 FF 265 -H 3

Breakdown of Type Designation Components:

• Motor Grundfos: Brand identifier.
• Frame size: Centre-line height of shaft, foot-mounted motor [mm]. Size, foot: [ ] = frame sizes 71, 80; S = small; M = medium; L = large.
• Length of stator core: A, B, C, D.
• Number of poles: 2, 4.
• Diameter of shaft end [mm].
• Flange version: [ ] = foot-mounted motor, type IM B 3; FF = free-hole flange; FT = tapped-hole flange.
• Pitch circle diameter [mm]: [ ] = IM B 3.
• Model: A (discontinued), B, C, D, F, H.
• Efficiency class: [ ] = NA; 1 = IE2 motor; 2 = IE1 motor; 3 = IE3 motor.

5. Construction

5.1 Mounting Designations

Describes standard mounting configurations according to IEC 60034-7.

• Flange-mounted motor (tapped-hole flange): IM B 14 (IEC Code I), IM V 18 (IEC Code II).
• Flange-mounted motor (free-hole flange): IM B 5 (IEC Code I), IM V 1 (IEC Code II).
• Foot-mounted motor: IM B 3 (IEC Code I).
• Foot-mounted motor (tapped-hole flange): IM B 34 (IEC Code I).
• Foot-mounted motor (free-hole flange): IM B 35 (IEC Code I).

5.2 Drain Holes

As standard, MG motors have drain holes in the drive end of the stator housing. If the motor is installed in a humid environment or areas with high air humidity, open the bottom drain hole to allow escape of water that may have entered the stator housing, for instance through condensation.

[Caution] If the drain plug is removed, the motor enclosure class will change from IP55 to IP44.

5.2.1 Number of Drain Holes

Diagrams illustrate drain hole configurations for different motor frame sizes (MG 71, 80; MG 90-132; MG 160, 180).

• One drain hole closed with a plug (flange can be turned 90° and 180°).
• Two drain holes closed with plugs (flange can be turned 180°).
• Three drain holes closed with plugs (flange can be turned 90° to both sides).
• Four drain holes closed with plugs (flange can be turned 90° to both sides).

5.3 Motor Bearings

The motor bearing type is stated on the nameplate.

5.3.1 Motors with Lubricating Nipples

Frame sizes 160 and 180 motors have lubricating nipples at both the drive and non-drive ends. Bearings are factory lubricated and should not be lubricated until commissioning. Lubricating intervals are stated on the nameplate with mechanical data. For lubrication and maintenance, see section 11.2 Motor Bearings.

5.4 Balancing

The rotor is dynamically balanced. As standard, the rotor is balanced with a half key inserted (cylindrical shaft).

5.5 Cable Entry/Screwed Connection

Motors are supplied without screwed cable entries. The table below shows the number and size of cable entry holes in the terminal box according to EN 50262.

6. Operating Conditions

6.1 Ambient Temperature and Installation Altitude

Grundfos motors are designed for operation up to 40 °C. MG motors can operate continuously at ambient temperatures up to 60 °C, but with a shorter bearing life (see section 11.2 Motor Bearings). Ambient temperature and installation altitude are critical factors for motor life. The table below shows maximum values, but these are not combined maximums (e.g., 60 °C at 3500 m cannot be sustained simultaneously).

If these values are exceeded, the motor must not be fully loaded due to the risk of overheating. Overheating can result from excessive ambient temperatures or low air density, leading to reduced cooling. In such cases, reduce the load or use a motor with a higher rated output.

The following charts illustrate the maximum motor load relative to temperature and altitude.

6.2 Frequency Converter Operation

All three-phase MG motors with phase insulation can be connected to a frequency converter.

6.2.1 Phase Insulation

MG 71 and 80: These motors do not have phase insulation as standard and are not suitable for frequency converter operation due to lack of protection against voltage peaks. Only motors with a rated voltage of 460 V or above have phase insulation.

[Caution] Frequency converter operation of MG motors without phase insulation will cause damage to the motor.

MG 90 to 180: These motors have phase insulation and are suitable for frequency converter operation, subject to the following precautions:

• Supply voltage up to 400 V: Check for phase insulation (motors with rated voltage ≥ 460 V have it).
• Supply voltage above 400 V: Check for phase insulation (motors with rated voltage ≥ 460 V have it). Fit a sine-wave filter between the motor and the frequency converter.

6.2.2 Acoustic Noise and Voltage Peaks

Frequency converter operation can increase acoustic noise and stress the motor insulation system due to voltage peaks. To prevent damage, adhere to IEC 60034-17 limits. An output filter can mitigate noise and voltage peaks.

How to eliminate problems with noise:

• Noise-critical applications: Fit an output filter between the frequency converter and the motor to reduce voltage peaks and noise.
• Particularly noise-critical applications: Fit a sinusoidal filter to reduce voltage peaks and optimize the power supply wave.

6.2.3 Cable Length

The cable length between the motor and frequency converter affects motor load. Use a cable that meets the frequency converter supplier's specifications.

6.2.4 Speed

MG motors are generally not suitable for oversynchronous operation. Contact Grundfos if oversynchronous operation is required. Oversynchronous operation involves running the motor at a frequency higher than 60 Hz, achievable with a frequency converter.

7. Mechanical Installation

Installation must be performed by authorized personnel in accordance with local regulations. Ensure the shaft rotates freely by hand.

7.1 Clearance

A minimum clearance of 50 mm must be maintained over and around the motor for sufficient air circulation.

7.2 Terminal Box Positions

Diagrams illustrate permissible terminal box positions. For vertically installed motors, the terminal box must not fall more than 10° below the horizontal plane. Ensure motor drain holes are positioned to allow condensed water to escape (see section 5.2.1).

7.3 Outdoor Installation

If installed outdoors, protect the motor against water and direct sunshine.

7.4 Foundation

Grundfos recommends installing the motor and pump on a foundation that is heavy enough to provide permanent and rigid support. The foundation must absorb any vibration, normal strain, or shock.

[Caution] Non-compliance may result in functional faults that damage motor components.

7.5 Alignment

Correct alignment is crucial to prevent bearing problems, vibrations, and potential shaft end fractures.

7.6 Fitting of Coupling Parts and Pulleys

Use suitable equipment and tools that do not damage motor bearings when fitting coupling parts or pulleys. Never force a coupling part or pulley into position; always carry out removal without pressing against the motor.

8. Electrical Installation

[Warning] Ensure the power supply cannot be accidentally switched on during electrical installation.

8.1 General Information

Verify the motor's suitability for the available power supply by checking the operating voltage and frequency on the nameplate. The voltage quality at the motor terminals must be within ±10% of the rated voltage during continuous operation, accounting for supply voltage variations and cable losses.

[Warning] The motor must be connected to an external mains switch.

8.1.1 Motor Protection

Single-phase motors: Equipped with built-in thermal protection (IEC 60034-11) against thermal overload.

Three-phase motors: Must be protected by a motor-protective circuit breaker according to local regulations. Motors from 3.0 kW are supplied with thermal switches (PTC) for overload protection.

[Warning] When servicing motors with thermal switches or thermistors, ensure the motor cannot start automatically after cooling.

8.2 Electrical Connection

Electrical installation should be performed by authorized personnel according to local regulations. The wiring diagram is located in the terminal box cover.

[Warning] Before opening the terminal box or dismantling the motor, switch off the power supply.

Single-speed motors typically have six winding terminals and at least one earth terminal.

[Warning] The motor must be earthed. Do not connect to the voltage supply until earthing is completed according to local regulations.

8.2.1 Single-phase Motor

Connect single-phase motors to the mains as per instructions in the terminal box cover.

8.2.2 Three-phase Motor

Three-phase motors can be connected in star (Y) or delta (D) according to IEC 60034-8. Refer to the terminal box cover for the wiring diagram. Voltage and connection type are stated on the nameplate.

Example: 380-415 D/660-690 Y. If the supply voltage is 380-415 V, connect in delta. If 660-690 V, connect in star.

9. Start-up

9.1 Measuring the Insulation Resistance

Measure insulation resistance before start-up and if there is any risk of moisture in the windings.

[Warning] Follow safety regulations (EN 50110-1) and equipment manuals during insulation resistance measurement.

Calculate the minimum permissible insulation resistance (R) by multiplying the motor's rated voltage (kV) by 0.5 megohm/kV. Stop using the motor if the insulation resistance falls below this value.

Example: For a 690 V rated voltage, the resistance must be > 0.69 kV x 0.5 megohm/kV = 0.35 megohm.

Measure at a winding temperature of 25 °C (±15 °C).

Procedure:

• Connect the megaohmmeter between phase and earth using a 500 V DC measuring voltage.
• Read the value on the megaohmmeter.

[Warning] Risk of electric shock during and immediately after measurement. Do not touch terminals until windings are de-energised.

If the minimum insulation resistance is not achieved, the windings are too moist and require oven-drying at 90 °C for 12-16 hours, followed by 105 °C for 6-8 hours.

[Note] Remove any drain plugs before heating.

9.2 Direction of Rotation

The direction of rotation is clockwise when viewed from the motor drive end, with mains conductors connected as per the terminal box cover diagram. The direction can be reversed by switching any two mains conductors.

[Caution] Some MG motors have a directed fan. The direction of rotation must match the motor's stated direction.

10. Operation

[Warning] During operation, the motor surface may be hot enough to cause personal injury.

10.1 Max. Number of Starts Per Hour

Refer to page 9 for details.

11. Maintenance

11.1 Motor

Inspect the motor at regular intervals based on its operating environment. Keep the motor clean to ensure adequate ventilation. Motors in dusty environments require more frequent cleaning and inspection.

Standard motors do not allow condensed water to escape. Open the drain hole at the lowest point of the motor to allow water ingress (e.g., from condensation) to escape.

11.2 Motor Bearings

11.2.1 Motors Without Lubricating Nipples

Bearings are greased for life, with an expected life of at least 18,000 operating hours at up to 40 °C ambient temperature. Higher temperatures reduce bearing life; a 10 °C increase reduces life by 50%.

Bearing Grease: Technical specifications must meet DIN 51825, K3N, or better. Grease viscosity: 50 cSt (mm²/s) at 40 °C and 8 cSt (mm²/s) at 100 °C. Grease filling rate: 30-40%.

11.2.2 Motors With Lubricating Nipples

Lubricate bearings with high-temperature grease as specified on the motor nameplate. Lubricating intervals are provided on the lubricating plate for 40 °C and 60 °C.

It is recommended to dismantle the motor after bearings have been relubricated five times. Clean and inspect bearings for damage; replace if necessary.

For seasonal operation (motor idle for over six months), lubricate bearings when taking the motor out of service.

Adhere to the specified relubrication intervals on the nameplate; failure to do so will reduce bearing life.

Reduced Lubricating Interval: Reduce the interval by a factor of 0.75 for dirty/dusty environments, and by 0.9 for very moist environments. Multiply factors if both conditions apply.

Grease Type and Quantity: Refer to the motor nameplate with mechanical data.

[Note] Never mix greases with different thickeners (e.g., lithium-based with polycarbamide-based).

12. Technical Data

• 12.1 Weight: See nameplate, WinCAPS, or WebCAPS.
• 12.2 Enclosure Class: See nameplate, WinCAPS, or WebCAPS.
• 12.3 Dimensional Sketches: See page 10.
• 12.4 Sound Pressure Level: See WinCAPS or WebCAPS.
• 12.5 Winding Resistances: See WinCAPS, WebCAPS, or MG Product Information, PI-052, section "Technical data".

13. Fault Finding

[Warning] Before starting fault finding, switch off the power supply and ensure it cannot be accidentally switched on. Motor service and fault finding must be performed by qualified personnel.

The table below lists common faults. Contact Grundfos if a specific fault is not covered.

14. Service

All repairs must be carried out in accordance with IEC 60079-19. Observe EN 50110-1 provisions until maintenance is complete and the motor is assembled.

14.1 Motor Bearings

Exercise care when replacing motor bearings.

[Caution] Do not expose bearings to impacts or shocks.

14.2 Service Documentation

Service documentation is available at www.grundfos.com > WebCAPS > Service. For questions, contact the nearest Grundfos company.

15. Disposal

Dispose of this product or its parts in an environmentally sound manner:

1. Use public or private waste collection services.
2. If not possible, contact the nearest Grundfos company or service workshop.

Appendix: Maximum Number of Starts Per Hour

2-Pole Motors

4-Pole Motors

Appendix: Dimensional Sketches

Diagrams illustrating the physical dimensions and mounting configurations of the motors.

Appendix: Dimensions Tables

Detailed dimensional data for 2-pole and 4-pole motors, including measurements for stator housing, shaft end, flanges, and cable entry points. The tables provide specific measurements (in mm) for various frame sizes and models, covering dimensions like L, EB, BB, K, AA, AB, etc., for different mounting types (IM B35, IM B34, IM B3) and cable entries.

Declaration of Conformity

This section provides the EU Declaration of Conformity for Grundfos MG and ML products, confirming compliance with relevant Council Directives. The declaration is presented in multiple languages, including:

• English (GB)
• Bulgarian (BG)
• Czech (CZ)
• German (DE)
• Danish (DK)
• Estonian (EE)
• Spanish (ES)
• Finnish (FI)
• French (FR)
• Greek (GR)
• Croatian (HR)
• Hungarian (HU)
• Italian (IT)
• Lithuanian (LT)
• Latvian (LV)
• Dutch (NL)
• Polish (PL)
• Portuguese (PT)
• Romanian (RO)
• Serbian (RS)
• Russian (RU)
• Swedish (SE)
• Slovenian (SI)
• Slovak (SK)
• Turkish (TR)
• Ukrainian (UA)
• Chinese (CN)
• Japanese (JP)
• Korean (KO)
• Bosnian (BS)
• Indonesian (ID)
• Macedonian (MK)
• Norwegian (NO)
• Thai (TH)
• Vietnamese (VI)
• Kazakh (KK)
• Malay (MY)
• Arabic (AR)
• Chinese Traditional (TW)
• Albanian (AL)

The declaration also lists the directives and standards used, such as the Low Voltage Directive (2014/35/EU) and Ecodesign Directive (2009/125/EC), and specifies that the declaration is valid when published as part of the Grundfos installation and operating instructions.

Grundfos Companies Worldwide

This section lists Grundfos contact information for various countries, including addresses, phone numbers, and telefax numbers.