DC Servo Motors

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Servo Repair International, Inc. repairs and replaces many of the brands of servo motors, including Kollmorgen.

Kollmorgen was founded in 1916 by Otto Kollmorgen to manufacture periscopes many of which were sold to the US Navy. In the 1960’s Kollmorgen expanded its business into the industrial control market by acquiring Inland Motors Corporation and others. Later, PMI became another motion control brand owned by Kollmorgen. Kollmorgen itself was acquired by Danaher in 2000.

Kollmorgen provides a wide range of motion control products and solutions. To serve customers using Kollmorgen motor powered systems, we provide our repair knowledge and replacement capabilities to keep their products and systems operational worldwide. Kollmorgen DC servo motors are used in a wide range of motion applications for both commercial and governmental end users.

One of the Kollmorgen DC servo motor products in use are the TT series dc servo motors. The Kollmorgen TT series motors cover a wide range of horsepower and speed requirements. In addition to a wide performance range, the motors may be designed with different options depending on the application requirements. There are many TT models operating in the field and presently being supported by Servo Repair International. Described below are brief summaries of some of the TT series and their general characteristics and options.


Kollmorgen Motors


If your motor is not represented below, please call us as our capabilities are always expanding!

If your motor is not a Kollmorgen, refer to our DC Servo Motor list to view a list of manufacturers we can service.

TT 2930 Series

The TT 2930 Series servo motors cover a .8 to 3 horsepower range and a maximum speed capability of 4500 RPM. Environmental protection type is typically IP44, but options such as oil seals and special sealing processes are not unusual in the industrial or governmental fields. The TT 2930 Series use field shell housings constructed of rare earth magnet material. The motors utilize integral shaft mounted tachometers for speed feedback to servo amplifiers. Many options are found installed in the motors such as thermostats, special flanges/connectors/brakes/shafts and keyways to name a few. Holding brakes are typically 24Vdc with a maximum holding torque of 6 ft-lbs.

TT 2950 Series

TT 2950 series motors are designed with low inertia armatures and strong (rare earth magnets) field frames. This combination results in motors with high acceleration and high torque for their physical size. The servo motors cover a 1 to 1.6 horsepower range. They range in speed from 2000 to 5000 RPM maximum. Maximum terminal voltage is 115Vdc. Environmental protection is typically IP44, but IP55 options exist along with other special sealing processes. The motors are used with or without tachometers (for speed feedback). Tachometers come in three different voltage scales. Motors operating in the field may include options such as Electromagnetic Fail-Safe Disk brakes, Encoders, Resolvers and Thermostats. The 2950 Series are found in 7 models covering the series power range.

TT 4000 Series

TT 4000 series motors come in power ranges from 1.75 to 3.7 horsepower (18 lb. ft. max) and speeds up to a maximum 3000 RPM. The field assembly is constructed with rare earth magnets eliminating thermal runaway conditions. A shaft mounted DC tachometer is a standard feature which provides speed feedback to the drive. Options include a 15 lb. ft. electromagnetic fail-safe brake and a resolver option which is used for position feedback. Motor is provided as a TENV assembly.

TT 4200 Series

TKollmorgen TT 4200 motor series cover a speed range of 875 to 3200 RPM and torques from 33 to119 ft.lbs. --- yielding a horsepower range of 3.7 to 6 horsepower. IP44 sealing, 18.9V tachometer, thermostat and round flange are a few of the standard features typically found in field operating units. Options utilized on motors may include: holding brakes, special windings, sealing and shafts. Different connectors, square flanges and shafts without keyways are also found on units sent in to us for repair.

TT 4500 Series

The TT 4500 series motors cover power ranges from 3 to 6 horsepower (35 lb. ft. cont. / 55 lb. ft. cont. fan cooled). Motor speeds cover a range of 1000 to 2400 RPM maximum. There are 3 models which cover the complete power range of this series. The TT 450 motors are designed as an inside-out motor which places the windings on the frame case. This allows rapid dissipation of generated heat thereby increasing the motor torque/size capacity (more torque for a smaller size motor). Motors operate as either TENV or TEFC depending on power needs. The motor is design to allow installation of resolver, fail-safe brake and air over package options.

TT 5300 Series

Kollmorgen medium to high power DC servo motor models are found in the TT 5300 series. The series contains models capable of 160 ft. lbs. peak and a maximum speed of 3000 RPM. Motors may contain DC tachometers, resolvers with gearing, encoders and fail-safe brakes. Units may be either constructed as TENV or with integral fan cooling.

TT 5800 Series

The Kollmorgen TT 5800 series of motors are utilized where heavy duty operation is required. Torque ranges from a continuous 60 lb. ft. in the TENV package to 100 lb. ft. with a blower added. The units can output 8 horsepower in the TENV model. Peak torque reaches 250 lb. ft. Motors may be equipped with a low ripple tachometer, geared resolver module and integral blower package. Temperature protection is provided by a normally closed thermostat. Environmental protection is provided by a front shaft seal.


Replacement Capabilities


Occasionally having an Kollmorgen DC servo motor repaired is not the best option.

Extensive motor damage or unacceptable lead times, may make replacement options a more intelligent and economical choice. Servo Repair International provides various replacement options for many Kollmorgen products. The older DC servo motors may be crossed over to newer products from Kollmorgen or other competing manufacturers. We can also provide our own direct replacement DC servo motors as replacements. Many times just a simple feedback device crossover may be needed to increase turnaround time and better performance.

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