DC servo motor
FAULHABER BP4 DC servo motor
Four-pole brushless DC servomotors built for maximum power density and dynamics in 22 and 32 mm diameters.
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Key specifications
| Outer diameter | 22–32 mm |
|---|---|
| Rated torque (max) | 0.158 Nm |
| Speed (max) | 34,500 rpm |
| Power (max) | 152 W |
| Voltage | 12-48 V |
Summarised in our own words from Dr. Fritz Faulhaber GmbH & Co. KG's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1
Notes on this data
Faulhaber lists 'torque up to' per series without saying whether it is continuous or peak; stored as torque_Nm_rated_max (converted from mNm). 2264 BP4: 59 mNm, 133 W, 34,500 rpm; 3274 BP4: 158 mNm, 152 W, 16,000 rpm.
Specify Motion is not affiliated with Dr. Fritz Faulhaber GmbH & Co. KG. FAULHABER and BP4 are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
FAULHABER BP4 replacement and alternative options
Use these supply-network options as a starting point for an engineering check. We can also help source the original FAULHABER part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.
A single 110 mm, 1.2 kW, 48 VDC servo motor giving 4 Nm at 3000 rpm for higher-power low-voltage systems, paired with Kinco FD1 and OD drives.
| Published maximum | BP4 | SMH Series Low-Voltage DC Servo Motor … |
|---|---|---|
| Rated torque | 0.16 Nm | 4 Nm meets or exceeds |
| Speed | 34,500 rpm | — |
| Power | 152 W | 1,200 W meets or exceeds |
Low-voltage (24-48 VDC) brushless servo motors with a 12-slot/10-pole low-cogging design, IP65 and a choice of optical or magnetic, incremental or absolute encoders. Matched to Kinco FD1 and OD drives for battery-powered and mobile machines.
| Published maximum | BP4 | SMC Series Low-Voltage DC Servo Motors |
|---|---|---|
| Rated torque | 0.16 Nm | — |
| Speed | 34,500 rpm | — |
| Power | 152 W | 3,000 W meets or exceeds |
Low-voltage brushless DC servo motors for 48 or 96 VDC systems, with a 12-slot/10-pole design, matched to the Kinco FD1X5 drive and aimed at robotics, CNC and automated lines.
| Published maximum | BP4 | SMK Series Low-Voltage DC Servo Motors |
|---|---|---|
| Rated torque | 0.16 Nm | — |
| Speed | 34,500 rpm | — |
| Power | 152 W | 5,000 W meets or exceeds |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
Typical applications
What a DC servo motor is
A DC servo motor, in current usage, is usually a low-voltage brushless permanent-magnet motor designed to run from a DC bus, typically 24 to 96 V, under closed-loop servo control. Electronically it works like an AC servo, with a three-phase stator commutated by the drive and encoder or Hall feedback on the shaft. The lower voltage means higher current for the same power, but suits battery-powered and safety-extra-low-voltage machines. Small precision brushless servomotors also fall into this group.
When engineers choose a DC servo motor
Choose a low-voltage DC servo for mobile robots, AGVs, battery equipment, medical devices and compact machines where mains voltage is impractical or unsafe. It allows simple power distribution and safe access. The trade-offs are current and power range: high current means thicker cables and higher losses, so power is typically limited to a few kilowatts. For mains-powered machines above that, an AC servo is usually simpler.
How to specify the FAULHABER BP4
Send these with your enquiry and an engineer can confirm the right BP4 variant or an equivalent:
- Bus voltage (V DC) and battery range
- Continuous and peak torque (Nm)
- Rated and maximum speed (rpm)
- Continuous and peak current (A)
- Feedback type and resolution
- Brake, IP code and frame size (mm)
- Drive and network interface
Common mistakes to avoid
- Sizing at nominal battery voltage without checking the low-charge end
- Undersizing cables for the higher current
- Ignoring regenerative energy into a battery or supply
- Mixing motor and drive feedback types that are not compatible
FAULHABER BP4: frequently asked questions
Can you help replace FAULHABER BP4 or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including Motion Control Products options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the FAULHABER BP4?
Four-pole brushless DC servomotors built for maximum power density and dynamics in 22 and 32 mm diameters. Published series figures include outer diameter 22 mm, outer diameter 32 mm, rated torque 0.158 Nm, speed 34,500 rpm. It is made by Dr. Fritz Faulhaber GmbH & Co. KG; Specify Motion can help source it or propose an equivalent.
Who makes the FAULHABER BP4?
The FAULHABER BP4 is made by FAULHABER (Dr. Fritz Faulhaber GmbH & Co. KG) and is listed here for engineers comparing options. Specify Motion is not affiliated with Dr. Fritz Faulhaber GmbH & Co. KG; brand names are used only to identify the product.
What is the outer diameter of the FAULHABER BP4?
The published series minimum outer diameter is 22 mm. Individual models and sizes in the BP4 range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the FAULHABER BP4?
We can assess suitable replacement options. On published figures, Kinco SMH Series Low-Voltage DC Servo Motor (SMH110D) and Kinco SMC Series Low-Voltage DC Servo Motors are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.
What is the difference between an AC servo and a DC servo motor?
Both are typically brushless permanent-magnet motors under closed-loop control. The main difference is the supply: AC servos are wound for drives fed from mains voltage, while DC servos are wound for low-voltage DC buses. DC servos suit battery and low-voltage machines; AC servos suit higher-power mains machines.
How does battery voltage affect a DC servo motor?
Motor speed is roughly proportional to available voltage, so as a battery discharges the top speed falls. Size the motor at the lowest working battery voltage. Also allow for regenerative energy during braking, which raises bus voltage and must be absorbed by the battery or a braking circuit.
Further reading: How to select a servo motor · How to select a dc motor · Servo and stepper motors
Other dc servo motor series
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Tell us how you use the FAULHABER BP4: the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.
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