Motor by Shaft Diameter: 11–100 mm Models

Of DRG Motor's 120 models, 116 have shaft dimensions on record, and they fall into 14 shaft diameters: 11, 14, 19, 24, 28, 38, 42, 48, 55, 60, 65, 75, 85, 100 mm. From 11 to 48 mm the diameter narrows the choice to one or two neighbouring frames, and every pole count in that frame carries the same shaft. From 55 mm upwards one diameter appears in several frames: 55 mm is used on 200L and on the 2-pole 225M, while 65 mm is used on the 4/6-pole 250M and on the 2-pole 280S, 280M, 315S, 315M and 315L — so shaft length E, key width F and pole count must be read together with the diameter.

Grey DRG three-phase electric motor – illustrative image for choosing a motor by shaft diameter

This article works from a known shaft towards the motor: you have a coupling, a pulley or the shaft of an old motor and want to know which DRG models match it. For the opposite direction, starting from power, see the motor shaft diameter by kW table; the models found here belong to the three-phase asynchronous electric motors range and are listed with product pages in the online motor shop.

Measure the shaft first: four dimensions, one diameter

Diameter alone can mislead: two frames with the same shaft share its length and key, but not their feet or flange. Measure in this order:

D – shaft diameter: with a caliper, away from the keyway and at two points along the shaft. A worn shaft gives two different readings; go with the value closest to a whole number in the table.
E – shaft length: from the shoulder against the bearing cover to the shaft end. It confirms the diameter group: in DRG data, 42, 48 and 55 mm shafts are all 110 mm long; 60, 65 and 75 mm shafts are 140 mm and 85 and 100 mm shafts 170 mm.
F – key width: the width of the keyway. It must match the keyway in the coupling or pulley hub.
G – key-seat dimension: the distance from the bottom of the keyway to the opposite side of the shaft; it indirectly gives the keyway depth.
DH – shaft end thread: the thread of the centre hole in the shaft end; it matters for pulley pullers and retaining washer bolts.

If your reading is not close to any value below (for example an inch-based 22.2 or 28.6 mm), the shaft may not be an IEC size; check the IEC and NEMA frame size conversion and send us the measurement.

Shaft identity table: D, E, F, G and DH

The shaft end dimensions below come from the B5 rows of the DRG catalogue. Each diameter has exactly one E×F pair, identical to the B3 values in the product records — so finding your measured D, E and F on the same row confirms that you read the diameter correctly.

Shaft diameter D (mm)	Shaft length E × key F (mm)	G – key-seat dimension (mm)	DH – shaft end thread
11	23 × 4	8.5	M4×12
14	30 × 5	11	M5×12
19	40 × 6	15.5	M6×16
24	50 × 8	20	M8×19
28	60 × 8	24	M10×22
38	80 × 10	33	M12×28
42	110 × 12	37	M16×36
48	110 × 14	42.5	M16×36
55	110 × 16	49	M20×42
60	140 × 18	53	M20×42
65	140 × 18	58	M20×42
75	140 × 20	67.5	M20×42
85	170 × 22	71	M20×42
100	170 × 25	86	M24×50

The general logic of shaft, key and coupling standards is covered in motor shaft diameter, key and coupling standards; this page only lists the values that correspond to DRG models.

11–28 mm shafts: small frames

In this range the diameter practically tells you the frame. There is a single DRG model with an 11 mm shaft; 19 mm appears only on frame 80, 24 mm on 90S and 90L, 28 mm on 100L and 112M. Aluminium and cast iron housings are both available here, and the AL and GG versions of a code carry the same shaft.

Shaft D×E, key F (mm)	Frame: poles, power	Housing (number of models)	Model codes
11×23, F 4	63: 2-pole, 0.25 kW	aluminium: 1	DRG-632-2-AL
14×30, F 5	71: 2/4/6-pole, 0.25–0.55 kW	aluminium: 5 cast iron: 1	DRG-711-4-AL DRG-712-6-AL DRG-711-2-AL +3 more: see 71 frames in the shop
19×40, F 6	80: 2/4/6-pole, 0.37–1.1 kW	aluminium: 6 cast iron: 5	DRG-801-6-AL DRG-801-4-AL DRG-801-2-AL +8 more: see 80 frames in the shop
24×50, F 8	90S: 2/4/6-pole, 0.75–1.5 kW 90L: 2/4/6-pole, 1.1–2.2 kW 90L compact: 2-pole, 3 kW	aluminium: 6 cast iron: 7	DRG-90S-6-AL DRG-90S-4-AL DRG-90L-6-AL DRG-90L-4-AL DRG-90L-2K-GG +8 more: see 90S, 90L frames in the shop
28×60, F 8	100L: 2/4/6-pole, 1.5–3 kW 112M: 2/4/6-pole, 2.2–4 kW 112M compact: 4-pole, 5.5 kW	aluminium: 8 cast iron: 7	DRG-100L-6-AL DRG-100L1-4-AL DRG-112M-6-AL DRG-112M-2-AL DRG-112M-4K-AL +10 more: see 100L, 112M frames in the shop

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38–48 mm shafts: medium frames

A 38 mm shaft is used on 132S and 132M, 42 mm on 160M and 160L, 48 mm on 180M and 180L. In DRG data aluminium housings go up to a 42 mm shaft; 48 mm and above are cast iron only. Note that 42 and 48 mm shafts have the same length (E 110 mm); diameter and key width (12 / 14 mm) tell them apart.

Shaft D×E, key F (mm)	Frame: poles, power	Housing (number of models)	Model codes
38×80, F 10	132S: 2/4/6-pole, 3–7.5 kW 132M: 4/6-pole, 4–7.5 kW 132M compact: 4-pole, 11 kW	aluminium: 8 cast iron: 7	DRG-132S-6-AL DRG-132S1-2-AL DRG-132M1-6-AL DRG-132M-4-AL DRG-132M-4K-AL +10 more: see 132S, 132M frames in the shop
42×110, F 12	160M: 2/4/6-pole, 7.5–15 kW 160L: 2/4/6-pole, 11–18.5 kW	aluminium: 4 cast iron: 7	DRG-160M-6-AL DRG-160M1-2-AL DRG-160M-4-AL DRG-160L-6-AL DRG-160L-4-GG +6 more: see 160M, 160L frames in the shop
48×110, F 14	180M: 2/4-pole, 18.5–22 kW 180L: 4/6-pole, 15–22 kW	cast iron: 4	DRG-180M-4-GG DRG-180M-2-GG DRG-180L-6-GG DRG-180L-4-GG

55–65 mm shafts: same diameter, different frames

This is where working from diameter most easily goes wrong. Up to frame 200L, all pole counts in a frame share one shaft; from 225M onwards the 2-pole models come with a smaller diameter. As a result, a 55 mm shaft is found on the whole 200L frame and on the 2-pole 225M; 60 mm on the 4-pole 225S, the 4/6-pole 225M and the 2-pole 250M; 65 mm on the 4/6-pole 250M and the 2-pole 280S, 280M, 315S, 315M and 315L. In DRG data the 65 mm shaft covers 2-pole models up to 200 kW.

Shaft D×E, key F (mm)	Frame: poles, power	Housing (number of models)	Model codes
55×110, F 16	200L: 2/4/6-pole, 18.5–37 kW 225M: 2-pole, 45 kW	cast iron: 6	DRG-200L1-6-GG DRG-200L1-2-GG DRG-200L-4-GG DRG-225M-2-GG +2 more: see 200L, 225M frames in the shop
60×140, F 18	225S: 4-pole, 37 kW 225M: 4/6-pole, 30–45 kW 250M: 2-pole, 55 kW	cast iron: 4	DRG-225S-4-GG DRG-225M-6-GG DRG-225M-4-GG DRG-250M-2-GG
65×140, F 18	250M: 4/6-pole, 37–55 kW 280S: 2-pole, 75 kW 280M: 2-pole, 90 kW 315S: 2-pole, 110 kW 315M: 2-pole, 132 kW 315L: 2-pole, 160–200 kW	cast iron: 9	DRG-250M-6-GG DRG-280S-2-GG DRG-280M-2-GG DRG-315S-2-GG DRG-315M-2-GG +4 more: see 250M, 280S, 280M, 315S, 315M, 315L frames in the shop

75–100 mm shafts: large frames

A 75 mm shaft is shared by the 4/6-pole 280S and 280M and the 2-pole 355M and 355L; shaft length is 140 mm on both. 85 mm appears only on 4/6-pole 315 frame models and 100 mm only on 4/6-pole 355 frame models, both with a 170 mm shaft length. DRG models with 400L, 400M frames have no shaft dimensions in their product records and are not included; please confirm the dimensions with us for those frames.

Shaft D×E, key F (mm)	Frame: poles, power	Housing (number of models)	Model codes
75×140, F 20	280S: 4/6-pole, 45–75 kW 280M: 4/6-pole, 55–90 kW 355M: 2-pole, 250 kW 355L: 2-pole, 315 kW	cast iron: 6	DRG-280S-6-GG DRG-280S-4-GG DRG-280M-6-GG DRG-355M-2-GG DRG-355L-2-GG +1 more: see 280S, 280M, 355M, 355L frames in the shop
85×170, F 22	315S: 4/6-pole, 75–110 kW 315M: 4/6-pole, 90–132 kW 315L: 4/6-pole, 110–200 kW	cast iron: 9	DRG-315S-6-GG DRG-315S-4-GG DRG-315M-6-GG DRG-315M-4-GG DRG-315L1-6-GG +4 more: see 315S, 315M, 315L frames in the shop
100×170, F 25	355M: 4/6-pole, 160–250 kW 355L: 4/6-pole, 250–315 kW	cast iron: 6	DRG-355M1-6-GG DRG-355M-4-GG DRG-355L-6-GG DRG-355L-4-GG +2 more: see 355M, 355L frames in the shop

One frame, two shafts: the 2-pole trap

In the frames below, DRG data gives the 2-pole model a thinner shaft. If your shaft comes from a 2-pole motor, moving to the 4- or 6-pole model of the same frame means changing the coupling or pulley bore; the other way round, a larger bore will not sit on the thinner shaft.

Frame	2-pole shaft D×E (mm)	4/6-pole shaft D×E (mm)	Key F (2 / 4–6-pole)
225M	55×110	60×140	16 / 18 mm
250M	60×140	65×140	18 / 18 mm
280S, 280M	65×140	75×140	18 / 20 mm
315S, 315M, 315L	65×140	85×170	18 / 22 mm
355M, 355L	75×140	100×170	20 / 25 mm

The same split applies to B5 flange orders: the catalogue's B5 table has two rows for these frames, and while the flange (P, N, M, S) stays the same, the shaft changes. For flange values see the B5 motor flange dimensions table.

Compact models have a shaft one step smaller

Compact models fit a given power into the next smaller frame, so they also use that frame's shaft. When searching by diameter, these three models show up with a higher rating than expected:

Power and poles	Compact model	Standard model	Shaft (compact / standard)
3 kW, 2-pole	DRG-90L-2K-GG (90L)	DRG-100L-2-GG (100L)	24 / 28 mm
5.5 kW, 4-pole	DRG-112M-4K-AL (112M)	DRG-132S-4-AL (132S)	28 / 38 mm
11 kW, 4-pole	DRG-132M-4K-AL (132M)	DRG-160M-4-AL (160M)	38 / 42 mm

Foot dimensions also differ between the compact and standard models.

Coupling and pulley matching checklist

Is the hub bore the same as your measured D? If the bore is one size off, change the hub, not the motor.
Is the hub keyway the same width as F, and is the key height consistent with G?
Is the hub longer than shaft length E? A pulley overhanging the shaft moves the load away from the bearing; seat it close to the shoulder.
Does the shaft end thread DH match your retaining washer or puller bolt?
Is the new motor's pole count the same as the old one? From 225M upwards, going from 2-pole to 4-pole changes the shaft.
Are the shaft height (frame number) and foot holes the same? Two frames with the same shaft sit on different bases.
For flange mounting, have the flange outer diameter, spigot, bolt circle and hole diameter each been checked?

The B14 small-flange table is not part of the DRG catalogue, so no B14 dimensions are given here. If you need a B14 or B34 connection, send the flange outer diameter, bolt circle, spigot and thread size on WhatsApp and we will check it. The full ordering steps are in the motor frame size order guide, and dimensioned drawings on the 2D technical drawings page.

Frequently asked questions

Which ratings are available as a 38 mm shaft electric motor?

In DRG data, 15 models have a 38 mm shaft: standard 132S and 132M frames from 3–7.5 kW, plus the compact 132M-4K at 11 kW. The shaft is 80 mm long with a 10 mm key.

I measured a 55 mm shaft — is it 200L or 225M?

Both carry a 55×110 mm shaft. If the motor is 2-pole and 45 kW, it is 225M; otherwise it is 200L. Check the foot holes and shaft height to be sure.

Does the same shaft diameter mean the same power?

No. In DRG data the 65 mm shaft is found on models from 37–200 kW; the shaft carries torque together with pole count. For power and torque calculations, use the electric motor calculator.

Send the measurement and we will find the model together

DRG Motor is an electric motor manufacturer, supplier and seller. Send the shaft diameter, shaft length, key width and, if possible, a photo of the old motor's nameplate, and we will work out the right frame and pole count with you. For a frame-by-frame model list, see the price list by frame number.

Send a photo of your current motor nameplate and we will find the suitable DRG model together.Send on WhatsApp

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Electric Motors Related to This Topic — Models and Current Prices

Suitability is not decided by power alone: compare the speed, voltage, mounting, shaft and fixing dimensions of your machine with the product data; if unsure, send us the nameplate of your current motor.