VFD vs Servo Drive: Key Differences
A side-by-side comparison of VFD and servo drive motor type, feedback, dynamic response, overload rating, cost, and applications for industrial engineers.
- Part number
- 1FK7103-2AF71-1QB0
SIMOTICS SSiemens 1FK7103-2AF71-1QB0 SIMOTICS S 1FK7-CT 36 Nm 3000 rpm Servo Motor with Brake
Siemens 1FK7-CT synchronous servo motor, 36 Nm, 4.4 kW, 3000 rpm, integrated holding brake, IP64, Drive-CLiQ encoder.
Description
About the 1FK7103-2AF71-1QB0
About the 1FK7103-2AF71-1QB0
The Siemens 1FK7103-2AF71-1QB0 is a SIMOTICS S 1FK7-CT synchronous servo motor rated at 4.4 kW with a 36 Nm standstill torque at 3000 rpm nominal speed. It runs from a 600 V DC bus, mounts in IM B5 (IM V1, IM V3) configuration with Flange 1, carries a Drive-CLiQ absolute single-turn 20-bit encoder (AS20DQI), IP64 protection, and includes an integrated holding brake.
Selection Notes
This QB0 variant adds an integrated holding brake to the 1FK7-CT 36 Nm / 3000 rpm winding, so it holds position on a vertical or overhung-load axis when drive power is removed; where a brake is not required, the brake-less version in the same frame is the lighter option. The brake raises moment of inertia to 112.000 kgcm2 and lowers shaft torsional stiffness to 108,000 Nm/rad compared with the same winding without a brake. The 20-bit single-turn Drive-CLiQ encoder (AS20DQI) gives absolute position feedback without a separate battery-backed multi-turn module.
Specification
Full specification
Engineering data 10
| Rated speed (100 K) | 3,000 rpm |
|---|---|
| Number of poles | 8 |
| Rated torque (100 K) | 14.0 Nm |
| Rated current | 11.5 A |
| Static torque (60 K) | 30.00 Nm |
| Static torque (100 K) | 36.00 Nm |
| Stall current (60 K) | 21.00 A |
| Stall current (100 K) | 26.00 A |
| Moment of inertia | 112.000 kgcm² |
| Efficiency | 93.0 % |
Physical constants 9
| Torque constant | 1.39 Nm/A |
|---|---|
| Voltage constant at 20º C | 89.5 V/1000*min¯¹ |
| Winding resistance at 20º C | 0.09 Ω |
| Rotating field inductance | 2.4 mH |
| Electrical time constant | 27.00 ms |
| Mechanical time constant | 1.46 ms |
| Thermal time constant | 65 min |
| Shaft torsional stiffness | 108,000 Nm/rad |
| Net weight of the motor | 33.0 kg Permanent-magnet synchronous |
Mechanical data 16
| Motor type | motor Compact |
|---|---|
| Shaft height | 100 |
| Cooling | Natural cooling |
| Radial runout tolerance | 0.050 mm |
| Concentricity tolerance | 0.10 mm |
| Axial runout tolerance | 0.10 mm |
| Vibration severity grade | Grade A |
| Connector size | M40 |
| Degree of protection | IP64 |
| Design acc. to Code I | IM B5 (IM V1, IM V3) |
| Temperature monitoring | Pt1000 temperature sensor |
| Electrical connectors | Connectors for signals and power rotatable |
| Color of the housing | Standard (Anthracite RAL 7016) |
| Holding brake | with holding brake |
| Shaft end | Feather key |
| Encoder system | Encoder AS20DQI: absolute encoder single-turn 20 bits |
Show all 61 specifications ↓ Show less ↑26 more values in Identification, Optimum operating point, Limiting data, Holding brake, Recommended Motor Module, Logistics.
Identification 5
| Part number | 1FK7103-2AF71-1QB0 |
|---|---|
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
Optimum operating point 2
| Optimum speed | 2,500 rpm |
|---|---|
| Optimum power | 5.4 kW |
Limiting data 4
| Max. permissible speed (mech.) | 5,000 rpm |
|---|---|
| Max. permissible speed (inverter) | 5,000 rpm |
| Maximum torque | 108.0 Nm |
| Maximum current | 84.0 A |
Holding brake 7
| Holding brake version | Permanent-magnet brake |
|---|---|
| Holding torque | 43.0 Nm |
| Power supply voltage | DC 24 V ± 10 % |
| Coil current | 1.0 A |
| Opening time | 300 ms |
| Closing time | 70 ms |
| Highest braking work | 3,380 J |
Recommended Motor Module 4
| Rated inverter current | 30 A |
|---|---|
| Maximum inverter current | 90 A |
| Maximum torque | 108.00 Nm |
| Page 1 of 1 | Generated Sun Nov 1 02:25:55 CET 2026 |
Logistics 4
| Shipping weight | 30.8 kg |
|---|---|
| Ships from | Türkiye |
| Dispatch | — |
| Stock | On request |
Source: manufacturer data · Last verified: 01 Nov 2026
Documents
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Quick answers
Questions about the 1FK7103-2AF71-1QB0
What is the rated current of 1FK7103-2AF71-1QB0?
The rated current of 1FK7103-2AF71-1QB0 is 11.5 A.
What motor power is 1FK7103-2AF71-1QB0 rated for?
The rated motor power of 1FK7103-2AF71-1QB0 is 4.4 kW.
What is the HS code of 1FK7103-2AF71-1QB0 for customs?
The tariff (HS) code on file for 1FK7103-2AF71-1QB0 is 85015220.
Where does 1FK7103-2AF71-1QB0 ship from, and how fast?
1FK7103-2AF71-1QB0 ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival.
Guides
Guides for servo drives
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Customer reviews
Series
Siemens SIMOTICS S
- Brand
- Siemens
- Series
- SIMOTICS S
