EMF Motor AŞ

Main spindle motor for Heavy Duty Lathe

A heavy duty Lathe with a 55kW AC main spindle motor was used for the machining of special alloy castings. The spindle motor was rotating the work piece via a gearbox and belt pulley system. The lathe had a capacity to turn material with a weight of 20 tonnes and a maximum diameter of 1 metre. Cast steel ingots weighing 5-10 tonnes were machined on the lathe. Despite very high energy consumption, the maximum cutting depth was 15mm per cut. During an 8-hour shift on the lathe, on average, 3 diamond tool inserts were broken. So 9 tool inserts were replaced most days. The lathe was retrofitted with an EMF SQM200-500 torque motor with a nominal power of 38kW at 300 rpm and torque of 1200Nm. The EMF motor is now connected directly to the gearbox via a coupling removing the need for a belt and pulley system. The EMF motor can be run to a maximum of 400rpm with field weakening. The EMF motor can operate with full torque from zero to maximum speed and provides constant speed throughout the range. With the old system, instant changes in load resulted in variations in speed. With the EMF technology with high resolution encoder feedback, the SQM Motor provides absolute constant speed throughout the range and is not affected by changes in the load.

• The old AC motor consumed a very high level of energy and was particularly inefficient at low speeds. The EMF SQM motor is highly efficient and so uses much less energy at all speeds.
• The old system could only remove a maximum of 15mm per cut. With the EMF SQM solution, the maximum cut is increased to 40mm.  
• With the old set up, the customer could machine an average of 6 pieces of the 5-10 tonne ingots.  With the EMF SQM motor set up the customer can now average 9-10 ingots.
• With the old system on average 9 diamond tool inserts were broken per day (225 per month). Since the motor has been upgraded to the EMF SQM, the breakages have stopped, saving the customer thousands of Euros.