Understanding Model Numbers for Rexroth and Indramat Servos


When you’re staring at a metal model name plate on an old Indramat servomotor and take a look at our list of motors we service, you might discover that your legacy model isn’t listed. This doesn’t mean, however, that we don’t service your model of Indramat servomotor. Just like the company name, the model numbers of Indramat, Rexroth, and Bosch Rexroth servos have changed over time. Model numbers on servos tell you a lot of information about the servomotor, from the series to different specifications.When Indramat became Rexroth, some of these model numbers and names changed.

Unlike car models that only have one name, every option on a servomotor is displayed through a complicated system of reference numbers that correspond with different features. It would be like saying “Lamborghini-Aventador-Giro brakes…” and so on until you listed off all the main components of the car. For an Aventador, that would be quite a long list.

Break down the model number

The first letters of your model number will tell you the series of the servomotor. Rexroth and former Indramat motors start off with a 3 letter series designator, like MSK, MKD or MAC. Series designators have to do with the motor design and purpose, and are very specific. While a MAC071b and a MKD071b look almost identical, in truth, they are motors that could never be substituted.

The next 3 digit group is the rotor size code, as in the above example where the rotor diameter is 071mm. The letter that follows the rotor diameter is the length, ranging from A to even E. The longer the motor is, the higher the torque, while maintaining a low polar moment of inertia.

After this, the type codes diverge in a number of separate ways depending on the series of the motor.

New for old?

Rarely can a new series motor be substituted for an older series motor, although Rexroth does have a conversion guide. However, motors are still available new in all of the digital series motors, and the older MAC motors are still repairable, so don’t toss those cores.

Legacy drives can get a bit confusing, but we have experienced staff who know about the history of each individual servomotor series and what options each series had available. These are all important details to know when you’re looking for service. We also keep a lot of units on hand for a wide variety of legacy Indramat servomotors so you never have to worry about scrambling for a part that you’re not sure will work.

Instead of trying to dig through the convoluted history of Indramat and Rexroth’s model numbers, call us and we’ll guide you to the right solution through our years of experience dealing with lots of different types of Indramat legacy servomotors, from LSF and LAR to MDD and MSK.

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