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
- 1FK7081-2AF71-1QB0
SIMOTICS SSiemens 1FK7081-2AF71-1QB0 SIMOTICS S 1FK7-CT 2.7 kW 12 Nm Holding Brake Servo Motor
Siemens 1FK7-CT servo motor, 2.7 kW, 12 Nm, 3,000 rpm, IP64, holding brake.
Description
About the 1FK7081-2AF71-1QB0
About the 1FK7081-2AF71-1QB0
The Siemens 1FK7081-2AF71-1QB0 is a SIMOTICS S 1FK7-CT synchronous servo motor rated 2.7 kW with 12 Nm standstill torque at 100K and a 3,000 rpm rated speed, built with an integrated holding brake. It runs on a 600 V DC link, uses natural cooling, and carries an IP64 enclosure with an absolute 20-bit single-turn DRIVE-CLiQ encoder (AS20DQI).
Selection Notes
The holding brake adds rotor mass, so inertia rises from the brakeless variant's 20.000 kgcm² to 23.500 kgcm² and shaft torsional stiffness drops from 109,000 to 76,000 Nm/rad — factor that into servo tuning if the axis needs high bandwidth. Choose this variant for vertical or gravity-loaded axes, where the brake holds the 12 Nm standstill torque during an E-stop or power loss instead of relying on the drive's active current. Rated current, speed, and power stay identical to the non-brake motor, so drive sizing does not change.
Applications
Typical use: vertical Z-axes, lift stations, and any DRIVE-CLiQ servo axis on SINAMICS S120/S210 where the load must not drop when power is removed.
Specification
Full specification
Engineering data 10
| Rated speed (100 K) | 3,000 rpm |
|---|---|
| Number of poles | 8 |
| Rated torque (100 K) | 8.7 Nm |
| Rated current | 6.8 A |
| Static torque (60 K) | 10.00 Nm |
| Static torque (100 K) | 12.00 Nm |
| Stall current (60 K) | 7.10 A |
| Stall current (100 K) | 8.70 A |
| Moment of inertia | 23.500 kgcm² |
| Efficiency | 93.0 % |
Physical constants 9
| Torque constant | 1.38 Nm/A |
|---|---|
| Voltage constant at 20º C | 88.5 V/1000*min¯¹ |
| Winding resistance at 20º C | 0.42 Ω |
| Rotating field inductance | 7.7 mH |
| Electrical time constant | 18.20 ms |
| Mechanical time constant | 1.35 ms |
| Thermal time constant | 45 min |
| Shaft torsional stiffness | 76,000 Nm/rad |
| Net weight of the motor | 15.9 kg Permanent-magnet synchronous |
Mechanical data 16
| Motor type | motor Compact |
|---|---|
| Shaft height | 80 |
| 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 | M23 |
| 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 | 1FK7081-2AF71-1QB0 |
|---|---|
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
Optimum operating point 2
| Optimum speed | 3,000 rpm |
|---|---|
| Optimum power | 2.8 kW |
Limiting data 4
| Max. permissible speed (mech.) | 6,000 rpm |
|---|---|
| Max. permissible speed (inverter) | 6,000 rpm |
| Maximum torque | 37.0 Nm |
| Maximum current | 30.0 A |
Holding brake 7
| Holding brake version | Permanent-magnet brake |
|---|---|
| Holding torque | 22.0 Nm |
| Power supply voltage | DC 24 V ± 10 % |
| Coil current | 0.9 A |
| Opening time | 200 ms |
| Closing time | 60 ms |
| Highest braking work | 1,400 J |
Recommended Motor Module 4
| Rated inverter current | 9A |
|---|---|
| Maximum inverter current | 27 A |
| Maximum torque | 34.10 Nm |
| Page 1 of 1 | Generated Sun Nov 1 02:21:30 CET 2026 |
Logistics 4
| Shipping weight | 14.2 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 1FK7081-2AF71-1QB0
What is the rated current of 1FK7081-2AF71-1QB0?
The rated current of 1FK7081-2AF71-1QB0 is 6.8 A.
What motor power is 1FK7081-2AF71-1QB0 rated for?
The rated motor power of 1FK7081-2AF71-1QB0 is 2.7 kW.
What is the HS code of 1FK7081-2AF71-1QB0 for customs?
The tariff (HS) code on file for 1FK7081-2AF71-1QB0 is 85015220.
Where does 1FK7081-2AF71-1QB0 ship from, and how fast?
1FK7081-2AF71-1QB0 ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival.
Guides
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Reviews
Customer reviews
Series
Siemens SIMOTICS S
- Brand
- Siemens
- Series
- SIMOTICS S
