If the failed motor's nameplate shows a standard IEC frame, a winding for a 50 Hz, 400 V supply and B3, B5, B14 or B35 mounting, the first choice is a standard model. If the shaft size, flange, voltage or frequency fall outside the standard, a motor prepared to order comes into play; in that case the preparation time and the return restriction must also be taken into account.

DRG-132S1-2 5.5 kW 3000 rpm cast iron frame DRG three-phase motor – standard motor or made-to-order motor

First see whether the old motor fits the standard

The decision is made from the nameplate and a few measurements. Note one by one the frame designation (e.g. 132S), shaft height H, shaft diameter and length D×E, foot hole spacing A×B and the flange type. If these values agree with their counterparts in the IEC table, a standard model can be considered among the options without changes on the machine side. To compare dimensions you can use the mounting dimensions in the DRG technical drawings.

Signs that it is non-standard

  • A supply voltage other than 400 V, or 60 Hz, on the nameplate
  • A stepped or extended shaft end, or one machined to a non-IEC diameter
  • A machine-specific flange with a non-standard bolt circle
  • The frame requiring a special paint colour or coating

Balancing speed against fit

When the line is down, small mismatches are often solved on the machine side: changing the coupling hub to suit the new shaft diameter or using an adapter plate can take less time than having the motor itself altered. That adaptation must, however, be approved by the machine maintenance team and, if needed, the machine builder. A voltage or frequency difference cannot be solved with an adapter; if the winding does not suit the supply, a motor prepared to order is required.

Motors prepared to order (special voltage, frequency, flange, shaft, paint or winding) cannot be returned. So no special request should be opened until the dimensions are confirmed.

Information needed for the decision

With the nameplate photo, shaft and flange dimensions, mounting position and the machine's load type to hand, the suitability check goes faster. You can compare standard options by power and speed in the three-phase motor list in the online shop, for example by setting the dimension table on the 5.5 kW 1500 rpm cast iron DRG-132S-4 page against your old motor.