Size counts for everything

Dean Palmer reports on a new, compact AC servo motor with built in driver and controller that is the same size as a traditional servo motor A servo motor with integrated driver and controller has been developed that is the same size as a traditional servo motor without a built in driver and controls. With a length of only 175mm for a 2.4Nm/750W motor, the MAC motor uses an extremely compact motor and electronics that utilise the latest technologies and manufacturing methods. Launched by Danish company JVL at the recent 'Herning Tech' trade fair in Denmark, the product is due to hit the UK this month. The motors are based on the same concept as JVL's previously introduced MAC motors, which have ratings from 50W to 140W. The specific control characteristics of a particular motor are determined by the module mounted in the motor housing. These modules are called 'expansion modules' and are similar to those used in the company's smaller MAC motor models. For the customer, the great thing about expansion modules is they buy only what they require for a specific application. Space is saved in the control cabinet, noise induced through the use of long motor cables is avoided, and errors due to cabling and components (the new motors have 30% less parts than its predecessors) are reduced significantly. The motor itself is a very powerful, compact, three-phase AC servo motor that can yield up to 3.9 and 6.8Nm peak torque. The motor measures 175mm by 115mm by 80mm and the flange is a standard servo flange, similar to Omron and Yaskawa flanges. JVL normally uses a 1st order regulator with its servo motors but the new MAC motors use a 6th order regulator, which is a mathematically modelled perfect regulator that is far better than a PID filter at handling non-linear and undamped systems. It means reduced installation and commissioning; a stiffer system with shorter positioning times; inexperienced users can now set up the servo system; oscillations due to non-linear mechanical systems are avoided; and you get minimum positioning errors during operation and set up. And users need only adjust a single parameter. This parameter is called the load factor, since it only depends on the inertia of the system. The greater the load on the motor, the greater the load factor. Expert users can continue to fine tune very complex, undamped systems using JVL's MacTalk software to select the 'filter selector' window and change the speed response, hardness and to optimise compensation for follow errors. The MAC motor can be controlled via ±10V in velocity or torque mode, with encoder feedback to the overall motion controller (PC or PLC). And the motor can replace any step- or servo system that is based on pulse/direction signals, without changing the PLC/PC controller software. The built-in electronic gear enables the motor to simulate any conceivable step resolution. On the power side, switching technology is used to ensure energy savings and therefore reduction of heat generation when the voltage is regulated to the internal control circuits. To ease the set up of the motor, users get Windows MacTalk software. Internet upgrades are an integrated part of the MAC concept. If an update of MacTalk or the motor's Firmware is required, the user simply selects 'update MacTalk' or 'update Firmware' and the software automatically downloads the latest version from JVL's Internet server. With expansion modules, JVL already has modules for Profibus DP, CANbus, CANOpen, Nano PLC and a high speed serial RS485 interface. But it is also now developing DeviceNet, Ethernet and USB connection modules and a Bluetooth module for wireless data transmission.