Complete guide for installation dimensions of IE2 and IE3 motors: B5 and B14 flanges
H1: Complete Guide to IE2 & IE3 Motor Installation Dimensions: B5 vs. B14 Flange
H2: Why Exact Mounting Dimensions Matter
When replacing an electric motor or designing a new drive system, matching the mechanical interface is critical. A millimeter mismatch in the flange or shaft can cause severe vibration, premature bearing failure, or a complete halt in production. This guide provides the standard IEC installation dimensions for IE2 and IE3 three-phase motors with B5 and B14 flange mountings.
H2: B5 Flange (Large Flange) Dimensions: Frames 80–180
The B5 flange is a large, through-hole flange primarily used for heavy-duty applications. The bolts pass through the motor flange and thread into the driven machine (like a gearbox or pump).
| Frame Size | Shaft Dia. (D) | Flange Dia. (N) | Bolt Circle (AD) | Keyway (F x G) |
|---|---|---|---|---|
| 80M | 19 mm | 130 mm | 165 mm | 6 x 21.5 mm |
| 90S/L | 24 mm | 130 mm | 165 mm | 8 x 27 mm |
| 100L | 28 mm | 180 mm | 215 mm | 8 x 31 mm |
| 112M | 28 mm | 180 mm | 215 mm | 8 x 31 mm |
| 132S/M | 38 mm | 230 mm | 265 mm | 10 x 41 mm |
| 160M/L | 42 mm | 250 mm | 300 mm | 12 x 45 mm |
| 180M/L | 48 mm | 250 mm | 300 mm | 14 x 51.5 mm |
H2: B14 Flange (Small Flange) Dimensions: Frames 80–112
The B14 is a smaller flange with threaded holes. Bolts pass through the driven equipment and thread into the motor flange. It is ideal for compact spaces, small gearboxes, and light-duty pumps.
| Frame Size | Shaft Dia. (D) | Flange Dia. (N) | Bolt Hole Ctr. (M) | Thread (T) |
|---|---|---|---|---|
| 80M | 19 mm | 80 mm | 100 mm | M6 |
| 90S/L | 24 mm | 95 mm | 115 mm | M8 |
| 100L | 28 mm | 130 mm | 160 mm | M8 |
| 112M | 28 mm | 130 mm | 160 mm | M8 |
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