Electrical coil winding machines are used to wind coils for motors, transformers, inductors and chokes. Coil winding equipment is used in a variety of wire winding, wire welding, and wire bonding applications. Some electrical coil winding machines are used in automated coil winding and assembly, magnet wire winding, transformer winding, or motor winding applications. Other coil winding equipment is used in solenoid winding, speaker and microphone coil winding, or air coil winding applications. Suppliers of electrical coil winding machines also provide equipment for medical device assembly, micro-electronic assembly, and RFID assembly. Specialized electrical coil winding machinery is used for fine wire welding and fine wire bonding (i.e., welding chips and flex chips). Electrical coil winding machines include motor coil, transformer coil, inductor coil, and choke coil winding machines. Motor coil winding machines are used to wind both single-phase and three-phase motor coil. They are designed for use with concentric or equal-size motor winding arbors. Medium-duty motor winders and heavy-duty motor winders are also available. Transformer coil winding machines are used to produce coils for power transformers that convert power-level voltages from one level or phase configuration to another. They are also used to wind coils for toroidal transformers, devices that consist of copper wire wrapped around a cylindrical core. In addition, electrical coil winding machines are used with inductors and chokes, passive components that resist changes in current and store energy in the form of a magnetic field. Electrical coil winding machines are available in both single-spindle and multi-spindle configurations. Single-spindle coil winders carry specifications such as wire range, pitch range, winding width, turn resolution, accuracy of spindle stop, speed range, torque, distance between centers, maximum winding diameter, power supply, dimensions, and weight. Multiple-spindle winding machines carry many of these same product specifications, and are available with 2, 3, 4, 6, 8, 10, 12, or 18 spindles. Additional specifications include spindle speed, spindle motor power, spindle stop position, maximum rotation diameter, and various axis travel measurements. In terms of features, electrical coil winding machines may include locking guards, optional cutters, an RS-232 or other communications interface, a computer monitor and keyboard, and integral storage capacity.