Electronic Thermal Overload Relay Symbol

Overload trips symbols for use in electrical pneumatic and hydraulic schematic diagrams.

Electronic thermal overload relay symbol. The wiring diagram of an overload relay is shown below and the connections of an overload relay symbol may seem like two opposite question marks otherwise like s symbol. Relay symbols and electromagnets. Available in svg png jpg dxf dwg formats. Though there are different types of overload relays the most common type is the bimetallic thermal overload relay.

The thermal and magnetic overload detections are typically used together in a motor protection relay. Thermal olr is based on the principle of deformation of a bimetallic strip on heating and the electronic overload relay is a microprocessor based device. The overload relay working function is discussed below. Citation needed electronic overload protection relays measure motor current and can estimate motor winding temperature using a thermal model of the motor armature system that can be set to provide more accurate motor protection.

Most of the time a small voltage or current is used to switch other voltages or higher currents that may be electromechanical or fully electronic type. Olrs are used in combination with the contactors. In a wiring diagram the symbol for overload contacts may look like two opposed question marks or an s.