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