Where to Buy an Electric Motor? A 12-Point Checklist for Ordering a Motor Online

An electric motor can be bought from three places: directly from a manufacturer or supplier, from a local dealer, or online. Whichever you choose, it is not the channel but the information you collect before ordering that decides whether you get the right motor: power, speed, voltage/connection, IEC frame, mounting type, shaft diameter×length and protection rating. These seven items come from the old motor's nameplate and a few measurements; once you have them, ordering online is as safe as ordering by phone.

DRG Motor is an electric motor manufacturer, supplier and seller; it lists its 0.25–355 kW three-phase motors model by model with technical data on the Buy Electric Motors Online page. This article does not explain how to use our store; it explains what to check so that you do not buy the wrong motor, whatever channel you use. The ordering steps (basket, order code, confirmation) are covered separately in Buying an electric motor online from DRG Motor.

Manufacturer, dealer or online: what does each route offer?

The table below compares the channels from a technical point of view. The yardstick is getting the right motor the first time; a wrong motor means removal, return shipping and a stopped machine.

We discuss separately when buying direct from the manufacturer really makes a difference in direct from the manufacturer or from a supplier. What matters here is this: in all three channels, the order is right or wrong according to the information you give.

Information to take from the nameplate before ordering

Take a photo of the old motor's nameplate, then fill in the rows below one by one. The example column shows the data sheet values of a 7.5 kW 1500 rpm motor (DRG-132M-4).

If the nameplate does not show the number of poles: find it from the speed

The speed on the nameplate is the rated speed under load and is slightly below the synchronous speed. Synchronous speed depends on the number of poles: n_s = 120 · f / p (f = 50 Hz). If the plate says 1460 rpm, the nearest synchronous speed is 1500, giving p = 120 × 50 / 1500 = 4 poles. The slip is (1500 − 1460) / 1500 ≈ 2.7%, which is normal. In the same way, about 2,900 means 2 poles (3000) and about 960 means 6 poles (1000). The torque on the plate must also match the power: P = T · n / 9550 = 49.1 × 1460 / 9550 ≈ 7.5 kW.

If the nameplate is unreadable: finding the frame by measurement

On a motor whose paint has worn off or whose plate has fallen off, three measurements identify the frame:

• Shaft height H: the distance from the foot seating surface to the shaft centre. It is the frame number itself: 90, 100, 112, 132, 160…
• Shaft diameter and length D×E: diameter with a caliper, length from shoulder to end with a rule. For example 28×60 mm on a 112M frame, 38×80 mm on a 132M frame.
• Foot hole spacing A×B: distance between hole centres across and along. At the same H, the letters S, M and L change the lengthwise spacing (B); that is the difference between 132S and 132M.

Comparing these three measurements and the outside diameter of the frame with the tables on the technical drawings page identifies the frame almost for certain. Several powers can share one frame, however, so match the power the machine needs to the frame separately. If the current can be measured (motor running), the motor current chart helps estimate power.

Ask for the data sheet, catalogue and dimension drawing

Whatever channel you buy from, ask the seller for these three documents, or check that they are on the page:

• Technical data sheet: rated speed, current (380/400/415 V), cos φ, rated torque, starting current and torque ratios. On every product page in our store these values are listed under "Electrical performance".
• Dimension drawing: A, B, C, D, E, H, K, L; on flange motors also P, M, N and hole diameter S. For a machine builder this is essential before drilling the frame.
• Mounting and connection information: terminal box position, cable entry size, bearing type. For example, the DRG-132M-4 has cable entry 2 × M32×1.5 and bearing 6208-ZZ-C3.

If this information is not written, ask for the same values by phone and note them. If what is on the page does not match your nameplate, ask before ordering.

How to read a DRG product code: DRG-<frame>-<poles>

In our store each motor code directly contains two pieces of information you take from the nameplate: the IEC frame and the number of poles. The middle part is the frame (801, 90L, 112M, 132M, 200L…), the final digit is the number of poles (2 = 3000, 4 = 1500, 6 = 1000 rpm). A 1 or 2 after the frame number marks two different power steps in the same frame (such as DRG-100L1-4 and DRG-100L2-4). A final letter K marks a compact model: the same power in one frame smaller.

So if your nameplate shows "132M, 1460 rpm", the code you are looking for is DRG-132M-4; the power and speed filters in the store take you straight there. The same code can exist in both cast iron and aluminium frames; the product page title states the frame material. If you are unsure which power is needed, the electric motor selection guide suggests power and speed from the application.

12-point checklist for ordering a motor online

1. A photo of the old nameplate has been taken; kW, speed, voltage and current are readable.
2. The number of poles has been confirmed from the speed (2,900 → 2, 1,450 → 4, 960 → 6 poles).
3. Supply voltage and connection (230/400 V star or 400/690 V delta) match the starting method in the panel.
4. The IEC frame number and shaft height H have been measured.
5. The mounting type is defined: B3, B5, B14 or B35; for a flange motor the flange outside diameter has been measured.
6. Shaft diameter and length D×E and key width fit the pulley or coupling hub.
7. Foot hole spacing A×B fits the base; if not, a spacer plate is planned.
8. The terminal box position (top/side) and cable entry size cause no problem on the machine.
9. Protection suits the environment: at least IP55 in dusty, damp or outdoor locations.
10. Frame material chosen: cast iron in heavy, shock-prone places, aluminium where low weight matters.
11. The technical data and dimension drawing on the product page have been checked against the nameplate.
12. Delivery address, vehicle access and unloading (forklift, crane) have been arranged in advance for heavy motors.

Shipping and checks on receipt

Motors from our store are shipped through contracted freight and courier companies. When the motor arrives, make these checks before signing; if there is damage, have it written on the delivery note:

• Crate and packaging: photograph any crushed, punctured or wet packaging.
• Shaft: no impact marks, scratches or bending on the shaft end; turn the shaft by hand, it should rotate freely and quietly.
• Feet and flange: on cast iron, no cracks in the foot lugs and no broken flange.
• Terminal box: cover, gasket and links in place; cable entries not broken.
• Fan cover: a dented fan cover rubs on the fan; report any rubbing noise.
• Nameplate: the code, kW, speed and voltage on the plate must match your order.

Have the mounting and electrical connection done by a qualified electrician; check the direction of rotation and no-load current on first start-up.

Motors in this power range

Some of the most searched powers and frames; all are among the 120 models in our online store:

• DRG-90L-4 – 1.5 kW – 1500 rpm – 90L cast iron
• DRG-112M-4 – 4 kW – 1500 rpm – 112M cast iron
• DRG-132M-4 – 7.5 kW – 1500 rpm – 132M cast iron
• DRG-160M-4 – 11 kW – 1500 rpm – 160M cast iron
• DRG-132M-4K – 11 kW – 1500 rpm – 132M aluminium

Click to see current prices and order these motors nowSEE PRICES →

Frequently Asked Questions

Where can I buy an electric motor?

Directly from a manufacturer or supplier, from a local dealer, or online. Whichever you choose, you will get the right motor if you have the power, speed, voltage/connection, IEC frame, mounting type, shaft D×E and IP rating.

Is it safe to buy an electric motor online?

Yes, if the product page clearly states technical data and dimensions and you have compared them with the old motor's nameplate and measurements. If it does not, ask the seller for a data sheet and dimension drawing before ordering.

Which motor replaces one with an unreadable nameplate?

The frame is found by measuring shaft height H, shaft D×E and foot hole spacing A×B; speed is taken with a tachometer on the running machine or from the machine data. For power, refer to the machine nameplate or the builder's data.

What information is needed to order a motor?

kW, speed (or poles), voltage/connection, IEC frame, mounting type (B3/B5/B14/B35), shaft diameter×length and protection rating. For a flange motor also give the flange outside diameter. In our store the mounting option is stated in the order note.

Send us a photo of your nameplate and we will find the right DRG model together: phone +90 (542) 666 11 11, e-mail [email protected], contact page.