SEW EURODRIVE DFY/DFS Synchronous Motor Guide

SEW DFY/DFS Synchronous Motor: Complete Guide to Installation, Connection, and Maintenance

In modern high-precision servo drive systems, synchronous motors have become the core executing components due to their excellent dynamic response and positioning accuracy. SEW-EURODRIVE's DFY series (and DFS56 series replacing early DFY56) permanent magnet synchronous servo motor, paired with MOVIDYN ®  Or MOVIDRIVE ®  Servo controllers are widely used in fields such as packaging, printing, handling, and machine tools. This article is based on the official operating manual (document number 0919 9519, version 02/2000), which systematically outlines the safety specifications, mechanical installation, electrical connections (including EMC compliance, rotary transformer, brake, and absolute encoder AV1Y), start-up preparation, maintenance (especially brake disc replacement and working air gap inspection), troubleshooting, and technical data of DFY/DFS synchronous motors. It provides a detailed technical operation guide for on-site engineers and maintenance personnel.

Product Overview and Model Description

1.1 Product Series

The DFY series synchronous motor uses permanent magnet excitation and has the characteristics of high torque density, low inertia, and strong overload capacity. Divided by power and installation size:

DFS56: Small motor (alternative model to DFY56), with or without brake (suffix B)

DFY71, DFY90, DFY112: Medium to large motors, optional with actuators and forced cooling fans (VY)

The motor is equipped with a standard rotary transformer (Resolver) as rotor position feedback, and can be optionally equipped with PTC thermistor (TF) or embedded temperature control switch (TH) to provide winding overheating protection. For absolute positioning applications, an AV1Y absolute encoder can be installed.

1.2 Nameplate Information

The motor nameplate contains the following key data: model, rated voltage, rated current, rated speed, brake voltage and current, protection level (IP), insulation level, ambient temperature range, etc. Before installation, it is necessary to verify whether the nameplate data is consistent with the project planning document.

Mechanical installation

2.1 Storage conditions

If the motor is not installed immediately, it should be stored in a dry, dust-free, and vibration free room with a temperature range of -25 ° C to+40 ° C. The allowable relative humidity is 85%, but condensation is not allowed. The installation altitude should not exceed 1000 meters (if exceeded, it needs to be downgraded for use, refer to the project plan).

2.2 Pre treatment after long-term storage

If the motor is stored for a long time, it is necessary to check whether it is damp:

Measure the insulation resistance of the winding (U, V, W to ground) using a 500V megohmmeter.

Insulation resistance is closely related to temperature. At 25 ° C, the minimum insulation resistance should not be less than 5 M Ω (see Figure 1 in the manual).

If the insulation resistance is insufficient, the motor must be dried by professionals until the resistance value exceeds the limit.

Simultaneously check the junction box/connector:

Internally clean and dry, without corrosion

The sealing gasket is intact

Tightening of cable sealing joints

Clean or replace components as necessary

2.3 Motor installation requirements

The motor or deceleration motor must be installed on a horizontal, vibration free, and torsion resistant support structure, and in the designated installation position.

Thoroughly remove the anti rust coating on the shaft extension end and flange surface (using standard solvents). Attention: The solvent must not penetrate into the bearings and oil seals to avoid damaging the materials.

Carefully align the motor with the driven equipment to avoid applying excessive radial or axial force to the motor shaft (following the allowed cantilever load and axial thrust).

It is strictly prohibited to apply impact or knocking to the shaft end.

Motors installed vertically must use VY forced cooling fans and be equipped with suitable protective covers to prevent foreign objects and liquids from entering.

Ensure smooth circulation of cooling air.

For components installed on the shaft in the future (such as pulleys and couplings), if the shaft extends with a key, dynamic balancing should be performed.

The surface temperature of the motor during operation may exceed 65 ° C, and anti contact protection measures must be taken.

2.4 Installation in damp or outdoor environments

The cable entry of the junction box should be installed facing downwards.

Use a suitable cable sealing joint (if necessary, use a reducing adapter).

Apply sealant to the threads of the sealing joint and sealing plug, tighten them, and then apply it again.

The cable entrance must be well sealed.

Clean the sealing surface of the junction box and its cover plate before reassembly, and bond the sealing gasket on one side. The brittle sealing gasket needs to be replaced.

If necessary, restore the anti-corrosion coating.

Check the protection level.

2.5 Tolerance

Shaft extension flange

Diameter tolerance: ≤ 50 mm is ISO k6,>50 mm is ISO m6. Centering shoulder tolerance: ≤ 230 mm is ISO j6,>230 mm is ISO h6

When installing transmission components according to DIN 332 DR type, it is recommended to use a center hole to protect the bearings

Electrical connection

Before making any electrical connections, safety regulations must be strictly followed (see Section 1 of the manual).

3.1 EMC compliant wiring

To ensure electromagnetic compatibility, the following principles should be followed (in conjunction with the installation instructions of the servo controller):

The signal line must use twisted pair shielded cables: reference signals (R1/R2), sine/cosine signals (S1/S4, S2/S3), and TF/TH thermal protection signals each use a pair of twisted pair cables.

The brake cable should be laid separately from the power cable; If separation is not possible, the power cable must be shielded to prevent electromagnetic interference from affecting the brake action.

3.2 Motor wiring

3.2.1 DFS56 Terminal Box Motor

Connect the power cable to the terminal block (cage spring clip): U, V, W, and PE (see Figure 2 in the manual).

Note: The rotation direction cannot be changed by exchanging the phase sequence (the rotation transformer determines the commutation logic).

Connect the rotary transformer signal and TF thermal protection to the other terminal busbar (Figure 3):

1: R1 (reference+), 2: R2 (reference -)

3: S1 (cosine+), 4: S3 (cosine -)

5: S2 (sine+), 6: S4 (sine -)

9: TH/TF (Motor Thermal Protection)

All wiring must be tightened.

3.2.2 DFY71~112 Terminal Box Motor

Connect the power cable to the terminal board (Figure 4): U, V, W, and Φ (PE).

The rotary transformer and TH/TF signal are connected to the terminal block (Figure 5), with pin definitions similar to DFS56, but with an additional 10th pin (not used).

All wiring must be tightened.

3.2.3 Motors with plug connectors (DFY56 and DFY71~112)

SEW provides prefabricated connecting cables. If making cables on your own, please refer to the plug assembly instructions in the appendix (SM11, SM21, SM32, SM41, etc.). Main pin allocation:

DFY56 power/brake plug (Figure 6):

Pin 1: U phase, Pin 3: W phase, Pin 2: V phase, Pin 4: PE (yellow/green)

Pin 5: Brake+, Pin 6: Brake-

DFY71/90/112 power plug (Figure 7):

Pin 1: U, Pin 2: V, Pin 3: W, Pin 4: PE

Rotary transformer/TF plug (Figure 8):

Pin 1: R1 (pink), 2: R2 (gray), 3: S1 (red), 4: S3 (blue), 5: S2 (yellow), 6: S4 (green), 9: TH/TF (white/brown)

All plugs use crimping pins (DFS56's rotary transformer plug is welded). Special crimping tools must be used, and the stripping length is shown in Appendix Table 1. Incorrect assembled pins should be removed using a dedicated ejector. Finally, secure the plug with a locking ring.

3.3 Brake Connection

The brake is electrically released and mechanically braked (spring brake after power failure). Important precautions:

Comply with the regulations of the Employers' Liability Insurance Association regarding phase loss protection.

The cross-section of the brake cable should be selected according to the braking current (see Appendix Table 3).

Due to the high DC voltage and current of the switch, it is necessary to use dedicated brake contactors or AC3 rated (EN 60947-4-1) AC contactors.

3.3.1 DFS56.. B brake

Directly controlled by 24V DC ± 10%.

3.3.2 DFY71~112. B Brakes

The brake rectifier (BM.. Series) or BSG brake control unit is installed in the control cabinet. The brake is connected using a 4-core cable (Figure 9):

The brake coil is powered by BM rectifier or BSG unit.

For elevator applications, the brake must be disconnected simultaneously on both the DC and AC sides (refer to Figure 8 on page 10 of the manual for dual circuit disconnection).

The brake plug (right angle type) is wired by the customer themselves, with pin definitions of 1, 2, 3, and PE. It is fixed with a central screw and must not be loosened when powered on.

3.4 Attachment Connection

3.4.1 Motor Thermal Protection (TF/TH)

TF (PTC Thermistor): Complies with DIN 44082. The resistance value is 20-500 Ω at room temperature, and>4000 Ω when overheated. When measuring, instruments with measuring voltage ≤ 7.5 V or current ≤ 1 mA should be used.

TH (Embedded Temperature Control Switch): Connected in series, the contact opens when the winding temperature exceeds the standard. Electrical data:

AC maximum 60 V (terminal box version allows 250 V AC), 2.5 A (power factor 1.0) or 1.6 A (power factor 0.6)

DC maximum 60 V, 1.0 A

3.4.2 VY forced cooling fan

The fan wiring diagram is shown in Figure 10:

Pin 1: Phase line L, Pin 2: Neutral line N, Pin 4: PE (yellow/green)

3.4.3 AV1Y Absolute Encoder

AV1Y absolute encoder with 1-meter connecting cable and matching plug (including crimping pin). SEW also provides extension cables for connecting MOVIDRIVE ®  Or MOVIDYN ®  controller. The pin allocation is as follows:

Pin signal indicates wire color

10 GND power supply ground brown (BN)

7 Vs+13~15~24 V DC white (WH)

14 Data+Serial Data Output, High Level="1" Black (BK)

17 Data - Serial data output, low level="0" purple (VT)

8 Pulse+clock current loop, 7 mA flowing to Pulse+="1" pink (PK)

9 Pulse - Clock current loop, 7 mA flowing to Pulse -="0" gray (GY)

Connection requirements:

Use twisted pair shielded cables, with large areas of grounding at both ends of the shielding layer (through shielding clips or encoder plug housings).

The pins are crimping type, and the stripping length is shown in Appendix Table 1. After crimping, a heat shrink tubing should be used for protection.

The plug is fixed with a locking ring.

Connect to MOVIDYN ® (Figure 11) MOVIDRIVE ® +  DPA11A (Figure 12) or MOVIDRIVE ® +  The detailed wiring diagram of DIP11A (Figure 13) can be found in the manual.

Start up

4.1 Pre startup inspection

All connections are correct and the plugs are securely fastened to prevent loosening.

All motor protection functions have been activated.

The drive system has no mechanical blockage.

There are no other sources of danger.

The motor has no transportation/storage damage (if stored for a long time, insulation should be checked according to section 2.2).

4.2 Startup steps

Follow the servo controller (such as MOVIDRIVE) ®  Or MOVIDYN ®） Start the operation according to the instructions. It is recommended to use software tools such as MOVITOOLS and MD_SCOPE to assist in parameter setting and debugging. For synchronous motors with rotary transformers, the controller needs to perform "motor parameter identification" or "static measurement" to determine the number of pole pairs and initial position offset.

Inspection and maintenance

Before carrying out any maintenance work, it is necessary to disconnect the power supply of the drive system and prevent accidental power on. Do not disassemble the plug connector when it is live. Only original spare parts can be used.

5.1 Inspection and maintenance cycle

The service life of each component is affected by various factors, and the inspection cycle should be determined according to the project planning document. Regularly conduct visual inspections. The replacement of bearings must be carried out by SEW training personnel, as the zero position of the rotary transformer needs to be recalibrated after disassembling the motor each time.

5.2 Required Tools

standard tool

Encoder installation tool (Stegmann EW1, order number 81B 001 003 001)

Double headed stud (DIN 938): M5 × 45 for DFY71, M6 × 60 for DFY90, M8 × 70 for DFY112

5.3 Brake maintenance

5.3.1 DFS56.. B brake

This brake is maintenance free.

5.3.2 DFY71~112. B Brakes

Check the working air gap (Figure 15):

Measure the stroke of the pressure plate during brake release. Allowable range: 0.25~0.8 mm.

Brake with manual release: Measure on the bolt of the release fork.

Brake without manual release: Remove the screw plug, screw in the pressure plate with a screw (see section 5.2) (not too deep to avoid damaging the coating), and measure the stroke. After measurement, remove the bolts and reinstall the plugs.

Replace the brake disc (Figures 16 and 17):

Remove connector (17) and flat washer.

Brake with manual release: Remove the manual release lever. Without manual release: Remove the screw plug (23) from the hole.

Use two auxiliary installation screws and washers to pull the pressure plate (4) towards the brake spring. The bolts specified in section 5.2 must be used, as other screws may damage the brake disc.

Spin out the coil body (11) with O-ring (20).

Pull out the brake disc (2).

Remove debris.

Slide in the new brake disc. Caution: Do not contaminate with oil or grease.

Insert the coil body (11) and O-ring. Remove the auxiliary installation screws.

Reinstall the manual release lever or seal plug. Reinstall the gasket and connector, and secure them with the center screw. When installing the manual release lever, ensure that the gap between the disc (13) and the release fork (10) is 2 mm to ensure the normal function of the brake.

When the brake is equipped with an AV1Y absolute encoder (Figure 18), the encoder needs to be removed before contacting the brake:

Loosen the center screw of the right angle connector.

Loosen bolt (11), rotate spring washer (10) outward, and then remove encoder (12) with half coupling (9). Attention: The coupling is a two-stage plug-in connection!

Remove the protective cover (6, DFY71 only) and flange fixing bolts (3). Use an 8mm wrench and then a 4mm hex wrench to loosen the expansion shaft counterclockwise, thereby disconnecting it from the coupling. Stegmann EW1 tool can be used.

Remove the center screw of the middle flange (8) and the right angle connector.

Loosen the coupling clamping screw (9) and carefully remove the coupling from the motor shaft.

Brake maintenance can now be carried out. When reassembling, operate in reverse to ensure that the runout of the speed measuring shaft is ≤ 0.05 mm, and the coupling must not withstand axial tension.

Brake installation (DFY71~112)

If the motor does not come with a brake at the factory, it can be installed later. The steps are as follows:

6.1 Motor preparation (Figure 19)

Remove the screws (213/19) from the housing cover plate and remove the cover plate.

Remove the shaft clamp ring (62/19) from the second shaft extension end.

Use a suitable puller to pull out the liner (308/19). Pay attention to protecting the shaft seat and the rotating transformer behind it.

The key (71/19) remains in its original position.

After heating the brake bracket (70/20), push it into the non drive end shaft extension.

Install a new shaft clamp ring (62/20).

Let the bracket cool to room temperature.

6.2 Pre assembly of brake coil (Figure 20)

Insert the O-ring (281/20) into the groove of the brake coil (286/20) socket.

Use a cross head screw (310/20) and a locking washer (294/20) to secure the terminal connection piece (295/20) to the coil (not tightened).

6.3 Pre assembly of brake system

Insert the pre installed brake coil into the coil body (54/20) and lock it axially with a snap ring (285/20). Be careful not to damage the O-ring.

Use the second cross head screw and locking washer to secure the coil to the coil body through the second opening on the coil body. The protective grounding is achieved through the screw connection between the terminal connection piece and the coil.

Push two parallel pins (300/20) into the holes on the coil body to a depth that does not protrude from the pressure plate (49/20).

According to the required braking torque (Appendix Table 4), insert the brake spring (265/20) symmetrically into the circumferential hole of the coil body.

Tighten one auxiliary mounting nut on each of the two cross head screws (56/20).

Place the pressure plate (49/20) on the parallel pin, thread two cross head screws through the reserved holes on the coil body (for manual release) and screw them into the pressure plate to the depth that the threads do not protrude from the pressure plate.

Tighten the nut to pull the pressure plate towards the coil body.

Place the O-ring on the coil body.

6.4 Install the brake onto the motor

Place the clamping plate (69/20) with its opening facing forward into the slot of the bracket (70/20).

Slide the brake disc (68/20) onto the bracket (hub facing forward). First, position half of the brake disc on the bracket, and then fully push it in while rotating (the motor shaft needs to be fixed).

The middle ring (299/20) has ribs on three sides and one side is flat. The design of the non drive end bearing cover is similar.

Place the O-ring (392/20) on the non drive end bearing cover.

Position the middle ring at the centering fit of the non drive end bearing cover and level it.

Place the O-ring (393/20), then place the pre installed coil body (with pressure plate) on the middle ring (with opposite planes), gently tighten with four cross head screws (213/20), and do not lock it temporarily.

Remove the auxiliary installation screws. Tighten the cross head screw.

Knock the protective cap (301/21) into the coil body. If there is no manual release, use a sealing plug (28/21) to seal the through-hole on the coil body.

6.5 Installation of manual release device (Figure 21)

Insert two rubber rings (47/21) into the through holes of the coil body.

Secure the release fork (53/21) in the coil body using two bolts (56/21), corresponding springs (57/21), washers (302/21), and nuts (58/21). The gap between the nut and the release fork should be 2 mm.

Insert the manual release lever (51/21) into the release fork.

6.6 Electrical Connections

Connect the right angle connector (303/21) according to the wiring diagram in section 3.3. Turn on and off the brake multiple times to check if it is functioning properly.

Troubleshooting

7.1 Motor malfunction

Possible causes and countermeasures of the problem

Check and restore connections for motor failure, broken leads, blown fuses, tripped circuit breakers, servo controller faults/wiring errors/setting errors; Check the controller and replace the fuse; Check the circuit breaker and overload; Check the controller and wiring

Difficulty or inability to start the motor. Controller settings are incorrect or overloaded. Check the controller and wiring

Steering error motor control signal error check controller and set value, exchange set value leads

Motor buzzing, mechanical jamming, lead failure of rotary transformer, brake not released, controller setting error, inspection of driving machinery; Check the lead wires of the rotary transformer; Check the brake system; Check the controller

Motor overheating and overload, insufficient cooling, forced fan not turning, high ambient temperature, working mode exceeding limit, controller not optimized, load checked with controller current; Improve cooling airflow; Check the fan wiring; Reduce power; Choose the appropriate motor; Optimize controller parameters

Excessive noise, bearing deformation or damage, vibration of rotating parts, foreign objects in the cooling fan, re align, check the driven machine, and replace the bearings; Eliminating imbalances; Clean the cooling air duct

7.2 Brake malfunction

Possible causes and countermeasures of the problem

The brake cannot release due to voltage errors, control unit failure, wiring errors, working air gap exceeding the limit (lining wear), power line voltage drop>10%, coil turn to turn short circuit or ground short circuit, applying the correct voltage; Replace the control unit and check the coil resistance; Check the wiring; Replace the entire brake disc; Ensure correct power supply voltage and wire diameter; Replace the brake and control unit

Brake does not brake, brake lining is worn, replace the entire brake disc

Brake delay action: The brake is cut off on both the AC side and the DC and AC sides (see wiring diagram)

Brake noise caused by gear wear due to start-up impact and torque oscillation due to improper controller settings. Check the drive configuration; Adjust the controller according to the instruction manual

If you need to contact SEW customer service, please provide: nameplate data of the motor and servo controller, description of the fault phenomenon, occurrence time and background, and possible causes.

Appendix Technical Data Summary

8.1 Brake Technical Data (Table 3)

Motor model: Maximum/minimum braking torque (Nm), total power W (10 ⁶ J), holding current IH (230VAC) (A), starting current IB (24VDC) (A)

DFS56M/B 2.5 / — — — 0.56

DFY71M/B 10 / 6 600 0.15 1.0

DFY90M/B 30 / 12 900 0.23 1.5

DFY112ML/B 60 / 35 1800 0.35 2.15

8.2 Brake coil resistance (Table 5)

Motor model 230VAC RB (Ω) 24VDC RB (Ω)

DFS56..B — 59

DFY71..B 1593 3.6

DFY90..B 402 2.5

DFY112..B 301 1.8

8.3 Connector Stripping Length (Appendix Table 1)

Connector type Maximum outer diameter (mm) Stripping length A (mm)

SM11 (DFS56) — 6 ± 0.5

SM21 (DFY71) 13.5 7 ± 0.5

SM32 (DFY90) 20 11 ± 0.5

SM46 (DFY112) 28 —