11 kW and 15 kW are the most sought-after medium-power electric motors in Turkish industry; from pumps to conveyors, from fans to compressors, these two powers appear in countless machines. Precisely for this reason, the most critical issue in buying an 11 or 15 kW motor is not technical complexity but getting the motor at the right speed, in the right mounting type and with fast stock delivery. This guide explains, from a buyer's point of view, the 2/4/6-pole speed options on 11 and 15 kW motors, which speed is preferred in which application, the advantage of stock delivery, and what you should send us for a fast, accurate quote. As HEM Motor, we supply 11 and 15 kW motors from stock in IE3 and IE4 efficiency classes, with B3/B5/B35 mounting options, cast iron bodies and IP55 protection.

11 and 15 kW electric motor selection: speed, pole and stock status

Why Are 11 and 15 kW the Most Sought-After Medium Powers?

11 kW and 15 kW fall within the operating range of the vast majority of industrial machines. These powers concentrate around the IEC 160 frame class and are common in both cast iron and aluminium bodies. Because many machine manufacturers and end users consume these two powers as a standard, at the right supplier these powers are usually delivered from stock; they can be shipped within hours without waiting for a production order. This is the biggest advantage for businesses that want to get a machine stopped by a failure back up as quickly as possible. We covered spare stock planning for medium-power motors in our article on the critical spare motor list for facilities.

Speed and Pole Selection: 2, 4 and 6 Pole

The most frequent critical choice when buying an 11 or 15 kW motor is the pole count, that is, the speed. The same kW does a completely different job at different speeds; this is why keeping the existing machine's speed is essential.

2-Pole (~2900 rpm)

Used in applications requiring high speed: high-pressure pumps, compressors, some fan and blower applications. At 11 and 15 kW, 2-pole motors are compact and high-speed.

4-Pole (~1450 rpm)

The most preferred speed in industry. 4-pole is standard in conveyors, gearbox drives, general machinery, mixers and many pump-fan applications. At 11 and 15 kW the widest stock is usually found in 4-pole motors.

6-Pole (~960 rpm)

Used in applications requiring higher torque and lower speed: heavy-starting conveyors, some mill and mixer applications. At 11 and 15 kW, 6-pole motors provide high torque at low speed.

If you want to examine in depth which pole count suits which job, our article on the asynchronous motor buying guide: which of 2, 4, 6 poles for which job? offers a clear decision table. You can find how the speed-power combination is determined in pumps, fans and conveyors in our article on motor power calculation: required kW for pumps, fans and conveyors.

2, 4 and 6-pole speed options on 11 and 15 kW motors

Application Areas: Where Are 11 and 15 kW Used?

These two powers cover a very wide range of applications:

  • Pump systems: Medium-flow centrifugal pumps, booster sets, irrigation pumps.
  • Fan and blower: Ventilation fans, dust collection and aspiration systems.
  • Conveyor and belt: Belt drives with 4 and 6-pole motors, geared conveyor systems.
  • Compressor: Medium-capacity screw and piston compressors.
  • General machinery: Mixers, agitators, crushing-grinding and industrial machines.

11 and 15 kW motors are often used with a gearbox. We explained matching the right motor to a gearbox with IEC frame and flange dimensions in our article on which electric motor fits a worm gear or NMRV reducer? For the gearbox side at these powers, you can review our helical worm gear reducers and worm gear reducers product pages.

Stock Delivery, Price and Correct Buying

For the most consumed medium powers like 11 and 15 kW, stock delivery means shipment within hours without waiting for a production order. We detailed the lead-time difference between stock delivery and a production order in our article on stock delivery or production order? electric motor lead times. On the price side, the cost at these powers varies by factors such as efficiency class (IE3/IE4), body material, mounting type and quantity. For a current and clear price, we always recommend requesting a quote; our article on factors affecting electric motor prices guides your budget planning.

You can review our 11 and 15 kW motor product family on the IE3 electric motor, IE4 electric motor and high-efficiency electric motors pages. You can reach all our articles on power and speed options via our power and speed options category, and the whole product range via the HEM Motor homepage. On understanding power correctly and avoiding order mistakes, our article on HP or kW? understanding electric motor power and ordering correctly is helpful.

11 and 15 kW Frame Size and Mechanical Compatibility

11 and 15 kW motors concentrate around the IEC 160 frame class, but the frame size and therefore the foot, flange and shaft dimensions may vary by efficiency class and manufacturer. If you are replacing an existing motor, mechanical compatibility is as important as the kW:

  • Frame size: The foot hole distances and centre height depend on the frame size; the same kW may come in a different frame.
  • Shaft diameter and key: The shaft diameter must match exactly for the coupling, pulley or gearbox connection.
  • Mounting type (B3/B5/B35): Confirm whether it is foot-mounted, flanged or combined with the existing motor''s mounting code.

To set up the shaft diameter, key and coupling compatibility correctly, our article on motor shaft diameter and key dimensions: correct ordering for coupling and pulley compatibility helps, and our article on frame size and power matching in cast iron motors clarifies frame-power matching. When replacing an old brand motor like-for-like, our article on replacing an old brand motor directly: how to select an equivalent motor provides step-by-step guidance.

Efficiency Class: IE3 or IE4 at 11 and 15 kW?

The 11 and 15 kW power range is in a band where IE3 is mandatory in terms of efficiency; at these powers IE3 is the lower limit and IE4 offers higher savings. Which one you choose depends largely on your operating hours:

  • High operating-hour (continuous) applications: IE4''s extra efficiency returns over time through energy savings; IE4 stands out in continuously running pumps, fans and compressors.
  • Low operating-hour applications: IE3 is often a balanced and economical choice.

We covered the investment decision between IE3 and IE4 at medium powers like 11 and 15 kW with an amortization calculation in our article on IE3 or IE4? the right electric motor investment for your business, and from which power and date the efficiency mandate applies in our article on IE3 and IE4 efficiency mandate: which motor from which date?

Correct Sizing: Should You Buy 11 or 15 kW?

Because the two powers are close, buyers often lean toward "let me buy 15 kW just to be safe". Yet choosing the motor too large both increases the initial cost and lowers efficiency and power factor when the motor runs at low load; this raises the risk of a reactive penalty. The right approach is to determine your machine''s actual power need and choose the most suitable power for it:

  • In applications where the load is calculable, like pumps and fans, calculate the required kW and leave a reasonable power margin.
  • If you are replacing an existing motor, keep the nameplate kW exactly; do not upsize without a real need.
  • If it will run at continuous full load, keep the power margin slightly wider.

We covered the effect of correct sizing on efficiency in our article on at what load should you run the motor? efficiency, power margin and correct sizing, and the method of calculating the required power in pumps, fans and conveyors in our article on motor power calculation: required kW for pumps, fans and conveyors. Our article on power factor (cos φ) and reactive penalty in high-efficiency motors explains the relationship between low-load power factor and reactive penalty.

Geared Drive in 11 and 15 kW Motors

11 and 15 kW motors are very often used with a gearbox; because applications like conveyors, mixers and augers require high torque at low speed. When matching a gearbox at these powers, the motor''s IEC frame size and flange type must match the gearbox''s input connection exactly:

  • Worm gear reducer: In applications requiring high reduction ratio and compact structure; common matching is found in the HEM body range up to 11 kW.
  • Bevel helical reducer: In conveyors and heavy drives requiring high efficiency and large torque; commonly used with 11 and 15 kW K-series reducers.

We covered whether you should buy a geared motor or a separate motor + gearbox in our article on geared motor or separate motor + reducer?, and the economic choice between worm gear and bevel helical reducers in our article on in which jobs is a K-series bevel helical reducer more economical than a worm gear? You can also review matching the right motor to a gearbox with IEC dimensions on our helical worm gear reducers product page.

Pre-Order Checklist: Error-Free Buying

To order an 11 or 15 kW motor without error, it is enough to convey the following information completely when requesting a quote. This list prevents the wrong motor from arriving and an unnecessary return-exchange process:

  • Power: 11 kW or 15 kW (by actual need).
  • Speed/pole: 2, 4 or 6 pole.
  • Mounting type: B3 (foot), B5 (large flange) or B35 (combined).
  • Efficiency class: IE3 or IE4.
  • Body material: Cast iron or aluminium.
  • Shaft diameter and special requests: For coupling, pulley or gearbox compatibility.

With this information we can quickly quote the exactly correct motor along with stock availability. We compiled which information speeds up the process when requesting a quote in our article on the 8 pieces of information to provide when requesting an electric motor quote, and the most frequent mistakes when buying a motor in our article on the 7 most frequent mistakes when buying an electric motor. If you are replacing an existing motor like-for-like, our article on avoid the wrong motor delivery explains the importance of matching with nameplate data.

Frequently Asked Questions

Is it a problem to fit a 15 kW motor instead of 11 kW?

Increasing power alone does not create an electrical problem if your machine's mechanical connection, frame size and shaft diameter match; however, an unnecessarily large motor is both more expensive and loses efficiency and power factor at low load. Also, since 11 and 15 kW may be in different frame sizes, the foot, flange and shaft dimensions may change. The best approach is to choose the power suited to your machine's actual power need; if unsure, send us the existing motor's nameplate and we will recommend the exact equivalent.

Which speed should I choose for an 11 or 15 kW motor?

Speed selection is determined by your machine. If you are replacing an existing motor, keeping the nameplate speed (pole count) exactly is essential: 2-pole ~2900 rpm, 4-pole ~1450 rpm, 6-pole ~960 rpm. In a new application, the most common 4-pole (1450 rpm) is the right choice for most conveyors, pumps and general machinery. If unsure about speed, describe the application to us and we will determine the right pole count together.

Are 11 and 15 kW motors delivered from stock?

Yes. Because 11 and 15 kW are the most consumed medium powers, they are usually delivered from stock in common speeds and mounting types and shipped quickly without waiting for a production order. This is a major advantage for getting a machine stopped by a failure running again as quickly as possible. Send us the exact configuration you need and we will share the current stock status.

Get a Quote

Do you need an 11 or 15 kW motor? Send us the speed (pole count), mounting type (B3/B5/B35) and efficiency class, or a nameplate photo of the existing motor, and we will quickly quote the right motor along with stock availability. Call now: +90 (532) 345 49 86 or reach us via our contact page. We offer project-based pricing for quantity purchases.