Electric Motor Supply for Machine Builders: From Sample to Series Production

Electric motor supply for machine builders runs in three steps: buy a single sample motor, approve it on the machine for dimensions and mounting, then plan series orders under the same code. The dimensions checked on the sample are the catalogue IEC frame values; for example the 4 kW, 1500 rpm DRG-112M-4 is a frame 112M motor with a 28 × 60 mm shaft and a B5 flange of 250 mm outside diameter and 180 mm spigot, drawing 7.95 A at full load on 400 V. Once these values are approved, series motors arrive with the same dimensions and your base, coupling or pulley never needs re-machining.

The reason for this order is simple: the machine design depends on the motor dimensions. Base holes, coupling hub, guard length and cable duct are all drawn around the motor; skip the sample approval and the error appears on the first series machine, on the assembly line. Electrical connection and protection settings must be done by a qualified electrician. All models suitable for a sample are listed by power, speed and frame among the 120 models on Buy Electric Motors Online.

From Sample Motor to Series Orders: a Three-Stage Supply Flow

1. Sample motor. The machine requirement (torque, speed, mounting) is defined and one motor is bought. The aim at this stage is to test the motor on the machine itself. On the prototype, the motor’s temperature rise, start-up and vibration are observed.

2. Dimension and mounting approval. The sample’s shaft, flange, foot and terminal box dimensions are compared with the DRG motor technical drawings and entered on the machine’s manufacturing drawing. That drawing should state the motor code, mounting arrangement (B3, B5 or B35), terminal box position and cable entry direction. This approved sheet is the reference for every later order.

3. Series order plan. Motor demand is split into batches according to your annual or periodic machine production plan. Each batch calls for the same code, mounting and terminal box orientation; if the machine changes (for example a new power step), steps 1 and 2 are briefly repeated for the new code.

Values to Measure When Approving the Sample

The table below shows catalogue values for two common frames. When the sample arrives, check them with a caliper and tape and compare with your machine drawing. Values come from the foot-mounted (B3) dimensions and the B5 flange table.

The row most often overlooked is shaft height H: if a motor of the same power but a different frame is chosen, the two shafts of a coupled drive no longer share an axis and shims must be added under the base. The second critical point is overall length L; there are 82 mm between 112M and 132M, and on enclosed machines the cover may not close.

What a Standard IEC Frame Gives the Machine Builder

The IEC frame number (71, 80, 90S, 112M, 132M…) standardises shaft height, shaft size and flange size. Designing your machine around a standard frame brings these benefits:

• Easy spare parts: Bearings carry standard numbers; frame 112M uses 6206-ZZ-C3, frame 132 uses 6208-ZZ-C3, frame 160 uses 6309-C3. Years later your machine can still be maintained with widely available parts.
• Motor replacement at your customer’s site: A failed motor can be replaced by one of the same frame without changing the base or coupling. That is a concrete advantage you can put in front of buyers.
• Power-step flexibility: A more powerful version of the same machine can keep the same flange. The 5.5 kW frame 132S and the 7.5 kW frame 132M share the 38 × 80 mm shaft and the 300 mm flange; only the foot hole spacing B grows from 140 mm to 178 mm.
• Compact option: Where space is tight, DRG-112M-4K delivers 5.5 kW in a 112M frame; the shaft stays at 28 × 60 mm and the connection dimensions match the 4 kW 112M motor.

Calculating Motor Power from Torque at the Design Stage

Machine builders usually know the torque and speed required at the machine shaft rather than the power. Power follows from P = T · n / 9550 (P in kW, T in Nm, n in rpm). Assumed example: a directly coupled machine needs 40 Nm at about 1460 rpm. P = 40 × 1460 / 9550 ≈ 6.1 kW; the next standard rating up is 7.5 kW. DRG-132M-4 delivers 49.1 Nm rated torque at 1460 rpm, roughly 1.23 times the calculated load. At start-up the motor gives about 98 Nm (Ts/Tn = 2.0); if the machine starts loaded, compare this with the load’s breakaway torque.

Motor power per machine varies widely by application; the definitive figure comes from your machine’s design calculation or prototype measurement. To try the calculation at different speeds, use the electric motor selection guide. The full-load current of the chosen motor also feeds the overload and cable selection in the machine’s control panel: a 7.5 kW 4-pole motor draws 14.3 A at 400 V, and other ratings are in the motor current chart.

Checklist for Integrating the Motor into the Machine

• Flange: For B5, do P / N / M and hole diameter S match the seat on the machine? Does the spigot (N) fit without play?
• Shaft: Do D × E and key width F suit the coupling or pulley hub? Is the hub no longer than the shaft?
• Terminal box orientation: Is the box on the side facing the panel, and can its cover be opened? Is the position (top, right, left) written on the order?
• Cable entry: Frame 90 comes with 1 × M25×1.5, frames 112M and 132 with 2 × M32×1.5, frame 160 with 2 × M40×1.5 glands; is your cable duct planned for this?
• Voltage and connection: Store motors up to 3 kW are 230/400 V and are star-connected on a 400 V supply; 4 kW and above are 400/690 V, run in delta on the supply and are suitable for star-delta starting. Confirm the supply voltage of the country where the machine will be sold.
• Protection: Is the IP55 protection stated on the product pages enough for a dusty, splash-exposed machine environment? If the motor faces direct wash-down water, plan a guard.
• Paint and finish: If paint matching your machine’s colour scheme is required, state it on the order; make sure paint does not cover the terminal box gasket or the nameplate.
• Direction of rotation: If the machine runs one way only, check direction on the first test run and mark the arrow on the machine.

How to Read a DRG Product Code

Reading the code correctly keeps the wrong motor off your manufacturing drawing. The code starts with “DRG-”, followed by IEC frame and length, and ends with the number of poles. Poles give the synchronous speed: 2 poles 3000, 4 poles 1500, 6 poles 1000 rpm.

When one frame has two power steps (such as 100L1 and 100L2), shaft and flange dimensions are identical; only power and current differ. So two power versions of your machine can share one base design. DRG Motor is a manufacturer, supplier and seller of electric motors; the codes are the same in the store, the catalogue and the technical drawings. The differences between buying from a manufacturer or a supplier are covered in our article electric motor direct from manufacturer or supplier.

4-Pole Models Machine Builders Choose Most Often

The models below are in the 1500 rpm class and cover the frames most used in coupled, belt and geared drives. Currents are for full load at 400 V.

Motors Often Requested as Samples

• DRG-90L-4 – 1.5 kW – 1445 rpm – 90L
• DRG-112M-4 – 4 kW – 1450 rpm – 112M
• DRG-112M-4K – 5.5 kW – 1460 rpm – 112M
• DRG-132S-4 – 5.5 kW – 1460 rpm – 132S
• DRG-132M-4 – 7.5 kW – 1460 rpm – 132M
• DRG-160M-4 – 11 kW – 1465 rpm – 160M

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Frequently Asked Questions

Can a machine builder place a series order without a sample motor?

It is possible but not recommended. Catalogue dimensions are standard, yet terminal box orientation, cable entry and coupling fit only show up on the machine. Approving these three points on a single sample prevents assembly errors in series production.

Which frame should be chosen for a 5.5 kW machine motor?

The standard choice is the frame 132S DRG-132S-4 (38 × 80 mm shaft). Where space is tight, the compact DRG-112M-4K gives the same power in a 112M frame with a 28 × 60 mm shaft. The choice depends on your machine’s flange and coupling design.

Where can I get the technical drawing of an electric motor?

Foot and flange dimensions by frame are on the DRG technical drawings page. When transferring the drawing to your machine drawing, also write the motor code, mounting arrangement and terminal box orientation.

How many amps does a 4 kW motor draw at 400 V?

The 4 kW, 1500 rpm DRG-112M-4 draws 7.95 A at full load on 400 V and 8.37 A on 380 V; the 3000 rpm DRG-112M-2 draws 7.45 A at 400 V. These values are the starting point for the overload setting in panel design.

Send us your machine’s motor requirement (torque, speed, mounting) and let us work out the sample and series plan together: +90 (542) 666 11 11, [email protected] or our contact page. All models: Buy Electric Motors Online.