These contractors are available in either SPDT (MT145-101-1), or DPDT (MT145-102-1), configurations. All contactors are supplied with four auxiliary switches; two "normally closed" for control of the solenoid voltage and two "normally open" for operation of signal lamps or to perform other related functions. Stock contactors have solenoids wired for 220 volt 50-60 cycle operation, but may be factory wired for 110 volt 50-60 cycle operation on special order, or may be re-wired in the field.
 An outstanding feature of these contactors is small size and compactness wherein width and length have been minimized with no excess space occupied beyond that required for adequate insulation. The specially treated Glass Polyester, (NEMA GPO-3), used for the movable and stationary contact bars provides added strength and durability as well as high voltage handling capability and resistance to arcing. Servicing and parts replacement are simplified since basic parts are generally accessible without disassembly.
The solenoids are more than ample to assure a positive action with a momentary application of voltage. In normal use and service the applied solenoid voltage is automatically disconnected by the "normally closed" micro-switch at the time the movable contact arm completes its rotation. This automatic disconnect feature assures only momentary application of voltage, regardless of "on" time of the external control switch.

The Multronics MT145-101-1 and MT145-102-1 RF Contactors are designed with Fit, Form, and Function to replace the E. F. Johnson MT145-101-1 and MT145-102-1 contactors and are primarily for RF switching applications at VLF, LF, MF, and HF. They are also ideally suited to DC voltage switching in high voltage rectifier circuits. Once switched, they require no "holding" voltage and are designed to operate with momentary application of power.