MRL Permanent Magnet Motors: An Overview
On average lifts are responsible for about 10% of the energy consumption in high-rise buildings. Due to this, one of the core goals of the industry is higher energy efficiency. One of the main factors that is responsible for this energy consumption is the type of drive system utilised. There have been various different kinds of drive systems used from the traditional hydraulic systems to the modern day direct drive systems.
The direct drive system uses servo drives along with large pole pair permanent magnet synchronous motors also know as torque motors. The energy consumption of the lifts using the direct drive system is less than half of those used in the earlier hydraulic systems. Along with lower energy consumption there are other advantages of using the direct drive system like zero oil consumption, low noise levels and higher speeds. Another advantage of using the direct drive system is that due to the compact size of the torque motor it is integrated in the lift shaft and therefore does not require a machine room thereby saving a lot of space.
Since the introduction of direct drive systems in the lift industry, the motor manufacturers have been designing new motors which have high torque, are compact in terms of size and have improved encoder interfaces. A number of different encoder interfaces have been used like incremental, hiperface and endat. The endat interface which is the most widely used, has various advantages over other interfaces such as electrical zero point setting and the capability to save customer specific data onto the encoder - which makes the installation and commissioning of these motors easier. The latest interface that is being used is the endat 2.2 interface, this has the advantage of being capable of monitoring key aspects of the motor (eg the winding temperature), which in turn enables engineers to closely monitor and maintain the motors.
NDC's ServoLab facility is now undertaking the repair and rebuilding of PM motors from MRL applications and supports their full function testing with all encoder interfaces.