315S, 315M, 315L Frame Motors: Shaft, Sizes

DRG Motor's cast iron housing with a 315 mm shaft height covers 14 models: 75–110 kW on 315S, 90–132 kW on 315M and 110–200 kW on 315L (model codes 315L1, 315L and 315L2). On all three frames, 2-pole motors have a 65×140 mm shaft and 4- and 6-pole motors a 85×170 mm shaft; what separates S, M and L is the lengthwise foot hole spacing B (406 / 457 / 508 mm).

Grey DRG three-phase cast iron electric motor – illustrative image for 315S, 315M and 315L frame models

All models belong to the three-phase asynchronous electric motors range; you can compare product pages such as DRG-315S-4, DRG-315M-4 or DRG-315L2-4 and other frames in the online motor shop. A motor of this size usually sits on a concrete or steel base next to a large fan, pump, compressor, mill or crusher. In a replacement order, the wrong pole count, the wrong L sub-code or the wrong B dimension upsets the coupling, the base and the lifting plan all at once.

Which DRG models use the 315S, 315M and 315L frames?

The frame letter in the model code is the IEC frame and the final digit is the pole count. Because DRG offers several ratings on the same 315L frame, it uses the sub-codes 315L1, 315L and 315L2; in the product records all three share the same IEC 315L B3 dimensions and differ in power and electrical values.

315S frame

Model	Power	Speed class / nameplate speed	Shaft D×E (mm)
DRG-315S-6 (6-pole)	75 kW / 100 HP	1000 rpm / 985 rpm	85×170
DRG-315S-2 (2-pole)	110 kW / 150 HP	3000 rpm / 2978 rpm	65×140
DRG-315S-4 (4-pole)	110 kW / 150 HP	1500 rpm / 1488 rpm	85×170

315M frame

Model	Power	Speed class / nameplate speed	Shaft D×E (mm)
DRG-315M-6 (6-pole)	90 kW / 125 HP	1000 rpm / 988 rpm	85×170
DRG-315M-2 (2-pole)	132 kW / 180 HP	3000 rpm / 2978 rpm	65×140
DRG-315M-4 (4-pole)	132 kW / 180 HP	1500 rpm / 1488 rpm	85×170

315L frame (315L1 / 315L / 315L2)

Model	Power	Speed class / nameplate speed	Shaft D×E (mm)
DRG-315L1-6 (6-pole)	110 kW / 150 HP	1000 rpm / 988 rpm	85×170
DRG-315L2-6 (6-pole)	132 kW / 180 HP	1000 rpm / 988 rpm	85×170
DRG-315L1-2 (2-pole)	160 kW / 200 HP	3000 rpm / 2980 rpm	65×140
DRG-315L1-4 (4-pole)	160 kW / 200 HP	1500 rpm / 1488 rpm	85×170
DRG-315L-2 (2-pole)	185 kW / 248 HP	3000 rpm / not in record	65×140
DRG-315L-4 (4-pole)	185 kW / 248 HP	1500 rpm / not in record	85×170
DRG-315L2-2 (2-pole)	200 kW / 270 HP	3000 rpm / 2980 rpm	65×140
DRG-315L2-4 (4-pole)	200 kW / 270 HP	1500 rpm / 1490 rpm	85×170

"3000 / 1500 / 1000 rpm" is the speed class (synchronous speed); the second value is the nameplate speed. For the DRG-315L-2 and DRG-315L-4, the DRG product record has no nameplate speed, current or torque value; please confirm these on the product page or with us.

Same power, different frame: why 6-pole moves up a frame

Guessing the frame from the kW rating is the most common mistake in the 315 family. The table shows, from DRG data, which frame each rating uses by pole count.

Power	2-pole (3000 rpm class)	4-pole (1500 rpm class)	6-pole (1000 rpm class)
75 kW	—	—	315S (DRG-315S-6)
90 kW	—	—	315M (DRG-315M-6)
110 kW	315S (DRG-315S-2)	315S (DRG-315S-4)	315L (DRG-315L1-6)
132 kW	315M (DRG-315M-2)	315M (DRG-315M-4)	315L (DRG-315L2-6)
160 kW	315L (DRG-315L1-2)	315L (DRG-315L1-4)	—
185 kW	315L (DRG-315L-2)	315L (DRG-315L-4)	—
200 kW	315L (DRG-315L2-2)	315L (DRG-315L2-4)	—

For example, 110 kW is on 315S in 2- and 4-pole form but moves to 315L in 6-pole (DRG-315L1-6); at 132 kW, 2/4-pole is 315M while 6-pole is 315L (DRG-315L2-6). The reason is torque: at the same power a 6-pole motor turns at roughly a third of the 2-pole speed, produces much more torque and needs a longer active housing. 6-pole ratings are 75, 90, 110 and 132 kW; 2- and 4-pole ratings are 110, 132, 160, 185 and 200 kW.

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65×140 versus 85×170: 2-pole and 4/6-pole shafts

Even two motors with the same frame and power can carry different shafts: the DRG-315S-2 and the DRG-315S-4 are both 110 kW on 315S, yet one has a 65×140 mm shaft and the other a 85×170 mm shaft.

Item	2-pole (all 315 frames)	4- and 6-pole (all 315 frames)
D×E – shaft diameter × length (mm)	65×140	85×170
F – key width (mm)	18	22
G – key-seat bottom dimension (mm)	58	71
DH – shaft end thread	M20×42	M20×42
Bearing record	6317-C3	6319-C3

Shaft diameter differs by 20 mm and length by 30 mm, so moving from 2-pole to 4-pole means re-machining or replacing the coupling hub or pulley, and the machine needs room for a shaft 30 mm longer. The bearing records also differ by pole count (6317-C3 / 6319-C3). See motor shaft diameter, key and coupling standards and the motor shaft diameter by kW table.

S, M and L: B dimension and overall length

The foot and housing cross-section dimensions are the same on all three frames:

B3 dimension	315S, 315M and 315L (mm)
H – shaft height	315
A – foot hole spacing (across)	508
C – shaft shoulder to front foot hole	216
K – foot holes	4–Ø28
AC – housing diameter	620
AD – axis to terminal box top	527

B and L are the dimensions that change:

Frame	B – lengthwise foot spacing (mm)	L – 2-pole (mm)	L – 4/6-pole (mm)
315S	406	1194	1224
315M	457	1304	1334
315L	508	1304	1334

B grows by 51 mm from 315S to 315M and by 51 mm from 315M to 315L, moving the rear pair of holes. In DRG records 315M and 315L show the same overall length L, so the difference appears on the base through B. When preparing a base, compare with the drawing on the 2D technical drawings or 3D technical drawings page.

B5 flange dimensions: two rows per frame

In DRG's B5 large-flange catalogue table, 315S, 315M and 315L each have two rows: one for 2-pole and one for 4-pole and above. The flange itself is identical in all six rows:

B5 flange dimension	All six rows (mm)
P – flange outer diameter	660
N – spigot (pilot) diameter	550
M – bolt circle diameter	600
S – flange hole diameter	24
T – spigot depth	6
LA – flange thickness	22

Catalogue row	Shaft D×E / key F (mm)	G (mm)	LB / L (mm)
315S – 2-pole	65×140 / 18	58	1054 / 1194
315S – 4, 6, 8, 10-pole	85×170 / 22	71	1054 / 1224
315M – 2-pole	65×140 / 18	58	1164 / 1304
315M – 4, 6, 8, 10-pole	85×170 / 22	71	1164 / 1334
315L – 2-pole	65×140 / 18	58	1164 / 1304
315L – 4, 6, 8, 10-pole	85×170 / 22	71	1164 / 1334

The shaft end thread is M20×42 in all six rows. So for a B5 flanged 315, the flange alone is not enough: the pole count decides the shaft (65×140 or 85×170 mm). Values for every frame are in the B5 motor flange dimensions table, and the FF large flange versus small flange difference is explained in B5 and B14 flange FF/FT difference. The B14 small-flange table is not in the DRG catalogue, so we give no B14/B34 dimensions for the 315 frame. If you need such a connection, send the flange outer diameter, bolt circle, spigot and thread size on WhatsApp and we will check it.

Current and torque

Torque values come from DRG records; the last column is a check with M = 9550·P/n (P in kW, n = nameplate speed in rpm).

Model	Current at 400 V (A)	Rated torque (Nm)	Check: 9550·P/n (Nm)
DRG-315S-6	136	727.2	9550·75/985 = 727.2
DRG-315M-6	161	869.9	9550·90/988 = 869.9
DRG-315S-2	185	352.8	9550·110/2978 = 352.8
DRG-315S-4	187	706	9550·110/1488 = 706
DRG-315L1-6	196	1063	9550·110/988 = 1063.3
DRG-315M-2	222	423.3	9550·132/2978 = 423.3
DRG-315M-4	224	847.2	9550·132/1488 = 847.2
DRG-315L2-6	232	1276	9550·132/988 = 1275.9
DRG-315L1-2	265	512.8	9550·160/2980 = 512.8
DRG-315L1-4	271	1027	9550·160/1488 = 1026.9
DRG-315L-2	not in record	not in record	—
DRG-315L-4	not in record	not in record	—
DRG-315L2-2	331	640.9	9550·200/2980 = 640.9
DRG-315L2-4	334	1282	9550·200/1490 = 1281.9

The 200 kW 4-pole DRG-315L2-4 draws 334 A at 400 V, the 2-pole DRG-315L2-2 331 A. With a 400/690 V (Δ/Y) connection the motor runs in delta on a 400 V supply. For cable and protection sizing use the motor current chart, the motor cable size calculator and the electric motor calculator; the terminal box has a 2 × M63×1.5 cable entry.

Transport, lifting and base mounting

A 315 frame cast iron motor is not a load to be lifted by hand or from a single improvised point. We do not quote weights here; select lifting equipment from the weight on the product record, nameplate or catalogue, and ask us if it is missing.

Lift the motor only by the lifting points on the housing; never sling it by the shaft, terminal box or fan cover.
Protect the shaft from impacts during transport; the bearings (6317-C3 / 6319-C3) are sensitive to shocks.
The base must be flat and rigid, with all four feet (4–Ø28 mm holes) in one plane. Correct any soft foot with shims before tightening the bolts.
With a coupling, re-check shaft alignment after bolting the motor down; compare the shaft height H 315 mm with the driven shaft.

Dimensions to confirm before ordering

Check	How to read / measure	Compare with 315 data
Nameplate speed	Existing motor nameplate	~2978 rpm → 2-pole; ~1488 rpm → 4-pole; ~985–988 rpm → 6-pole
Shaft D×E, key	Caliper; shoulder to end; keyway width	65×140 mm / F 18 (2-pole) — 85×170 mm / F 22 (4/6-pole)
Lengthwise foot spacing B	Front to rear hole centres	406 (S) / 457 (M) / 508 (L) mm
Spacing A, H, holes	Hole centres; base to shaft axis	A 508, H 315, 4–Ø28 mm
B5 flange	Outer diameter, spigot, bolt circle, holes	P 660 / N 550 / M 600 / S 24 mm
Connection and cable	Terminal box, supply voltage	400/690 V (Δ/Y); 2 × M63×1.5

If the nameplate is unreadable, the shaft diameter is a strong clue: in the 315 family a 65 mm shaft appears in DRG data only on 2-pole models. Ordering steps are in the motor frame size order guide, and the price list by frame number lists models frame by frame.

Frequently asked questions

What is the difference between 315L, 315L1 and 315L2?

All three are IEC 315L frames; in DRG records they share B 508 mm, A 508 mm and H 315 mm. The sub-code separates different ratings on the same frame (on 2-pole, for example, 160, 185 and 200 kW). Always quote the full model code.

Does a 110 kW 6-pole motor fit a 315S frame?

Not in DRG data: the 110 kW 6-pole DRG-315L1-6 is on 315L with a B dimension of 508 mm. On 315S the only 6-pole model is the 75 kW DRG-315S-6.

Do the 132 kW 2-pole and 4-pole motors have the same feet?

Yes, both are 315M (B 457 mm). The shaft, however, changes from 65×140 mm to 85×170 mm and the key from 18 mm to 22 mm.

Technical confirmation and ordering

DRG Motor is an electric motor manufacturer, supplier and seller. To find the right 315 model, send a photo of the existing nameplate with the shaft diameter and length, the B dimension or the flange dimensions. For background on large cast iron frames see cast iron frame and high kW motors and the DRG technical and product catalogue.

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.