SR25 Drill Motor

Very strong and robust.

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SR25 Drill Motor

SR25 Drill Motor

The SR25 Drill Motor is based on the principle of the switched reluctance motor (SR = switched reluctance). The stator is very robust built simple. Its rotor consists of a shaft on which there are strung several single steel laminations. Thus the motor works without any turning windings or short circuit rotor and therefore also without commutator and wear-affected carbon brushes.
There are no gear speeds and thus is lighter than the bigger SR35. 

This motor saves resources, it consists almost only of steel and copper. The commutation (alternating current feed of the stator poles) is managed by electronic power which gets its orders from a microcomputer. The speed over the whole capacity range almost constant, therefore the start drilling is made easier, the wear is reduced and the efficiency of the drill bit is increased. The SR25 works with six fine adjusted speeds which can be chosen while drilling on the robust keypad with a +/- button, and thereby shows in a clearly readable LED display, the suitable drilling diameter to the operator. 


Motor protection

The motor current is controlled corresponding to the requirements and limited to the maximum. Therefore it cannot be overloaded.
Via thermal protective switches the actual appearing temperature of the motor and the electronic power is registered and depending on that will be switched off safely. Thus the motor and the electronic power are protected directly against thermal overload which may occur on insufficient cooling.

Oil bath lubrication with oil pump

The gear is lubricated optimally in all general purposes and offers a high efficiency on long lifetime and little maintenance. 

Safety Clutch

Due to the new motor fitted with a novel multi flange clutch which protects the operator, the tools and the motor itself against high mechanical overload. The higher number of friction surfaces guarantees a nearly constant releasing torque even after a few hundred overload cycles. Through the limiting of the torque by the motor management the wear out of the clutch is extremely low.

Soft turn

By choosing the Soft Turn, the drill bit is assembled on its own. Speed and torque are hereby highly reduced for safety reasons. 

Water Cooling

The motor together with electronic power is optimally cooled by a patented water cooling system. It is already used successfully in the DK42 and DK52 and the SR35, SR65 and SR75. 
Hereby the water flows controlled through the interspace between the motor case and the case sleeve. Through this arrangement the electrical part is completely separated from the cooling and thus the electrical safety is guaranteed.

Metal Case

The skin is completely made of aluminum. Therefore very robust, thermally stable and prepared for professional use. The casing is protected at the sensitive side by a laterally running carrying handle. 


The operating hours counter which is integrated in the micro controller allows for work for 300 hours permanently. Then the operator is shown that the motor is to be maintained by only starting, when the start button is pressed three times.

Technical Data

Voltage 230V
Current 16A
Motor 3700W
Output Power 2700W
Speeds 230*-280-340-410-490-570
Torque 110Nm
Length 440mm
Weight 14.7kg
Drilling diameter 70-370mm
Tool fixture 1 1/4


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SR25 Drill Motor

SR25 Drill Motor