## 1 Introduction  
The rise in the construction of cable-supported bridges has led to challenges regarding the safety and serviceability of bridges [1, 2]. The serviceability of a cable-supported bridge is directly related to the cables and anchorages that support the bridge deck, as well as the vibration problems of the dynamic behavior of the bridge [3]. Cable vibration causes discomfort to users, and can lead to public complaints as well as traffic accidents. Additionally, in a severe wind environment, fatigue failure of cables or anchorages can cause serious threats to the safety of bridges [4]. Generally, cable vibration control and monitoring are operated using separate systems, each incurring a maintenance cost. Controlling the vibration of the cable incurs maintenance costs associated with replacement, repair and reinforcement for maintaining the functions of the anchorage and damper [5]. Vibration monitoring requires measurements, equipment for data acquisition and processing, transmission, and a system for operating and controlling it; thus, maintenance costs for supplying power while maintaining the functions are incurred. Because the electromagnetic damper performs a power supply function for vibration monitoring and vibration control of the cable simultaneously, it can minimize the maintenance cost for each function. The electromagnetic damper is based on a mechanism utilizing a force that interferes with the movement of the permanent magnet due to the external force as a damping force. The damping force is generated by the electromagnetic induction of the coils or the eddy current of the conductor. Because the electromagnetic damper is driven in a non-contact operation mode, friction can be minimized and used semi-permanently. Therefore, repair and replacement costs due to leakage problems are not incurred, which account for most of the maintenance costs for non-permanent dampers. Additionally, it is possible to harvest energy through self-generation and supply power to the vibration monitoring and control system via strategic control that accumulates power in the storage battery and consumes it as needed [6; 7]. By controlling the circuit connected to the coil, the damper can be used as a passive, active, or semi-active vibration controller. Owing to this possibility, research on electromagnetic dampers for vibration control of stayed cables has been actively conducted; however, there is a scope for improvement for practical purposes. This is because the control force is weak, the damping density is low, and the price is high compared with the conventional dampers, owing to the permanent magnet. In terms of utilizing permanent magnets and coils, generators and motors have similar driving mechanisms with electromagnetic dampers. Therefore, studies on cable damping using a commercial motor and a linear-rotating converter have been attempted [8]. An intuitive damping system was implemented by connecting the cable and the motor using sprocket-wheel and chain. However, there is a possibility of mechanical loss due to backlash and friction, and additional devices, including motion converters, are complex and difficult to apply to the site. In addition, the motor must be energized at all times to maintain tension of the chain. Numerical analysis of electromagnetic damping and an energy harvesting system according to control methods has been proposed [9]. However, the modeled electromagnetic damper is configured such that the permanent-magnet synchronous machine connected to the electric circuit transmits power to the ball screw through the timing belt. Thus, mechanical loss similar to that of rack and pinion occurs, so there is a limit to durability. This study aims to finally implement an autonomous damping and monitoring system. For this, semi-permanent driving characteristics and compact structure of the electromagnetic damper must be premised.