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B5 Flange-Mounted Electric Motors
B5 flange-mounted electric motors are one of the large-flange electric motor types widely used in industry. In the B5 mounting form, the motor has no foot connection; the motor is fixed directly to the machine, gearbox, pump housing, fan system or special connection plate via the large flange connection on its front side. Thanks to this structure, a more compact, properly aligned and robust connection is obtained between the motor and the equipment it drives.
B5 flanged electric motors are especially preferred in applications where the motor must be connected directly to the machine. The B5 mounting type is frequently used in gearbox inputs, pumps, fans, mixers, agitators, compressor systems, packaging machines, textile machines, food machines, agricultural machines, concrete batching plants and general machine manufacturing applications.
What Is a B5 Flange-Mounted Electric Motor?
A B5 flange-mounted motor is an electric motor with a large flange connection. In these motors, the connection is made through the flange located on the front cover part of the motor. Since the motor has no feet, it is not connected to the chassis from the bottom of the body. Instead, it is fixed to the machine with bolts using the connection holes on the flange.
The B5 mounting type provides a great advantage especially in gearbox systems and direct-coupled connections. Since the motor shaft and the machine shaft operate on the same axis, more proper power transmission is achieved when the correct dimension is selected. For this reason, B5 type electric motors offer a reliable solution in coupled, flanged and directly connected systems.
What Should Be Considered When Selecting a B5 Flange-Mounted Motor?
When selecting a B5 flange-mounted electric motor, motor power and speed alone are not sufficient. The flange dimensions, shaft diameter, shaft length, centering diameter and connection hole dimensions must definitely be checked.
If the wrong flange dimension is selected, the motor may not connect to the machine or a centering error may occur. This situation can lead to problems such as vibration, bearing failure, coupling breakage, strain at the gearbox input, or a drop in pump-machine performance.
The main dimensions to be considered in B5 flange-mounted motors are as follows:
D dimension: The motor shaft diameter.
E dimension: The motor shaft output length.
M dimension: The center diameter of the flange connection holes.
N dimension: The flange centering spigot diameter.
P dimension: The outer diameter of the flange.
S dimension: The flange connection hole diameter.
Key dimension: The keyway dimension on the shaft, important for the coupling, pulley or gearbox connection.
Common Dimensions in B5 Flange-Mounted Electric Motors
The table below is of a general reference nature for B5 large-flange electric motors. Dimensions may vary according to the manufacturer, motor series, number of poles and special design. Before ordering, verification must definitely be made with the technical drawing or catalog dimension of the motor.
| Frame Type | D Shaft Diameter | E Shaft Length | M Flange Hole Diameter | N Centering Diameter | P Flange Outer Diameter | S Hole Diameter |
|---|---|---|---|---|---|---|
| 63 | 11 mm | 23 mm | 115 mm | 95 mm | 140 mm | 10 mm |
| 71 | 14 mm | 30 mm | 130 mm | 110 mm | 160 mm | 10 mm |
| 80 | 19 mm | 40 mm | 165 mm | 130 mm | 200 mm | 12 mm |
| 90S / 90L | 24 mm | 50 mm | 165 mm | 130 mm | 200 mm | 12 mm |
| 100L | 28 mm | 60 mm | 215 mm | 180 mm | 250 mm | 15 mm |
| 112M | 28 mm | 60 mm | 215 mm | 180 mm | 250 mm | 15 mm |
| 132S / 132M | 38 mm | 80 mm | 265 mm | 230 mm | 300 mm | 15 mm |
| 160M / 160L | 42 mm | 110 mm | 300 mm | 250 mm | 350 mm | 19 mm |
| 180M / 180L | 48 mm | 110 mm | 300 mm | 250 mm | 350 mm | 19 mm |
| 200M / 200L | 55 mm | 110 mm | 400 mm | 350 mm | 450 mm | 19 mm |
| 225S / 225M | 60 mm | 140 mm | 400 mm | 350 mm | 450 mm | 19 mm |
| 250M | 65 mm | 140 mm | 500 mm | 450 mm | 550 mm | 19 mm |
| 280S / 280M | 75 mm | 140 mm | 500 mm | 450 mm | 550 mm | 19 mm |
| 315S / 315M / 315L | 80–85 mm | 170 mm | 600 mm | 550 mm | 660 mm | 24 mm |
| 355M / 355L | 100 mm | around 210 mm | 740 mm | 680 mm | 800 mm | 24 mm |
Dimensions Suitable for the Turkish Market in High-Power B5 Motors
In high-power electric motors, the flange and shaft dimensions must definitely be checked separately. In the Turkish market, the 355 frame and Ø100 mm shaft diameter are widely used especially in 315 kW and 355 kW 1500 rpm motors. For this reason, in high-power B5 flange-mounted motor orders, the motor power, speed, frame type, shaft diameter, shaft length, key dimension, flange diameter and centering diameter must be evaluated together.
The high-power B5 motor dimensions frequently encountered in the Turkish market are generally as follows:
| Power | Speed | Common Frame | Common Shaft Diameter | Flange Type |
| 250 kW | 1500 rpm | 315HT / 355 frame | Ø100 mm | Large flange |
| 315 kW | 1500 rpm | 355M | Ø100 mm | Large flange |
| 355 kW | 1500 rpm | 355M / 355L | Ø100 mm | Large flange |
| 400 kW | 1500 rpm | 355L | Ø100 mm | Large flange |
Advantages of B5 Flange-Mounted Motors
B5 flanged electric motors offer the possibility of a direct and robust connection to the machine. Thanks to their footless structure, a more compact mounting can be made. They save space especially in gearbox systems, pumps and fan applications.
Thanks to the flange connection, the motor and machine can be aligned more easily on the same axis. When the correct dimension is selected, vibration is reduced, power transmission becomes more efficient and the life of the connection elements is extended. The B5 mounting type also provides practicality in maintenance and replacement processes.
The Difference Between B3 and B5 Mounting
B3 mounted motors are footed and are connected to the chassis via the feet under the motor body. B5 mounted motors, on the other hand, have no feet; the motor is connected to the machine via the front flange.
In short:
B3 motor: Footed motor
B5 motor: Large-flange motor
B35 motor: Footed + large-flange motor
In machine design, the correct mounting type should be selected according to whether the motor will be connected to the chassis or directly to the machine body.
Hem Motor B5 Flange-Mounted Electric Motors
As Hem Motor, we offer powerful, efficient and long-lasting solutions to industrial businesses in B5 flange-mounted electric motors. With a wide range of power options from 0.55 kW to 355 kW, we provide B5 flanged motor options suitable for fan, pump, compressor, gearbox, conveyor, mixer, packaging machine, concrete batching plant and machine manufacturing applications.
Our B5 flange-mounted electric motors stand out with their advantages of high efficiency, strong body structure, 100% copper winding, the use of quality bearings and a design suitable for heavy operating conditions. Thanks to the motor options in the IE3 and IE4 efficiency classes, energy savings are achieved, while long-lasting and reliable operation is obtained thanks to the strong mechanical structure.
The correct flange and shaft dimension selection is especially important in high-power motors. As Hem Motor, we offer solutions in frame, flange and shaft dimensions suitable for Turkish industrial applications in high-power B5 flange-mounted electric motors such as 315 kW, 355 kW and 400 kW. We support our customers in the correct motor selection by performing technical dimension checks before ordering.
For your B5 flange-mounted electric motor needs, Hem Motor is your reliable solution partner with the advantage of a wide stock, a favorable price policy and fast delivery support.