Can a motor be ordered online without knowing the pump's connection dimensions?

It is not recommended. Even if the power and speed are correct, the motor will not fit if the frame size, mounting type, flange or shaft dimensions do not match the pump. Taking a few measurements before ordering takes far less time than sending the wrong product back and forth.

Dimensions to gather before ordering

• The old motor's nameplate: kW, speed, voltage and, if shown, the IEC frame size (e.g. 112M)
• Mounting type: foot-mounted (B3), flange-mounted (B5), foot and flange (B35) or small flange (B14)
• Flange outside diameter and pitch circle diameter of the fixing holes
• Shaft diameter (D), shaft length (E) and key width
• For foot-mounted motors, shaft height (H) and foot hole spacing
• Whether the pump and motor are joined by a coupling, a belt or a common shaft

If the nameplate is illegible, measurements taken with calipers and a tape measure, plus photos of the motor from four sides, will also do the job.

The same power can mean different dimensions

For motors of the same kW rating, shaft and frame dimensions can vary with speed. A few examples from the DRG model list:

How wrong dimensions affect returns and exchanges

If the wrong power, speed or mounting type has been chosen, the product can be exchanged for a suitable model provided it is unused, not installed and complete in its packaging; any price difference is communicated and shipping is paid by the buyer. However, if the motor has been fitted to the pump and tried, or prepared with a special flange or shaft on request, it falls outside the scope of returns. This is why dimensions should be confirmed before ordering.

Mounting codes are explained in detail in the mounting type ordering guide. Once you have the dimensions, you can match them using the shop list, where every product page shows shaft and frame data; for example, you can review the dimensions of the 4 kW 1500 rpm aluminium model.